JP7299924B2 - A rechargeable lithium ion battery having an anode structure containing a porous region - Google Patents

Description

This application relates to rechargeable batteries. More specifically, the present application includes an anode structure composed of a substrate that includes a porous semiconductor region having two different porosities and a non-porous semiconductor region underlying the porous semiconductor region. It relates to a capacity rechargeable lithium ion battery.

In recent years, for example, computers, mobile phones, tracking systems, scanners, medical devices, smart watches, power tools, remote systems and sensors, electric vehicles, internet of things (IOT), and fitness devices. There is an increasing demand for electronic devices such as One of the drawbacks of such electronic devices is the need to include a power source within the device itself. Batteries are typically used as power sources for such electronic devices. The battery should have sufficient capacity to power the electronic device at least for as long as the device is in use. Sufficient battery capacity can result in a power source that is significantly heavier and/or larger than the rest of the electronic device. Therefore, a smaller and lighter power source with sufficient energy storage is desired. Such power sources can be realized in a combination of smaller and lighter electronic devices with lithium-ion materials acting as charge carriers. Since lithium is the lightest and most electropositive charge carrier ion in the periodic table of elements, lithium ion batteries and capacitors are considered optimal for smaller, higher energy density energy storage devices.

In addition to the demand for lightweight energy storage devices that provide high energy density (high capacity), the demand for faster charging speeds (ie fast charging kinetics) is also a current demand in the consumer market. For the next generation of batteries, it would be desirable if a battery could be fully charged in 10 minutes or less, in order to meet consumer demand in markets such as electric vehicles, portable telecommunications, IOT, and sensors. In the case of electric vehicles, if a consumer has to wait longer than 10 minutes to charge his/her vehicle, the battery-powered electric vehicle is limited to the user's schedule and consequently their range of travel. may be added. Thus, the use of fast charge rate batteries in the electric vehicle market will help create a viable electric vehicle market to compete with and possibly replace gasoline-powered automobiles.

Another drawback of conventional batteries is that some batteries contain potentially flammable and toxic materials that can leak, resulting in safety hazards and costly product recalls. There is As a result, these batteries are subject to government regulation, which can damage the product's reputation. The risk of battery leakage can be increased by the formation of cracks within these batteries. These cracks are probably caused by internal stresses due to charge/discharge cycling of the battery.

In addition, for batteries containing solid electrolytes, dendrite formation in these batteries has been shown to reduce battery life performance. Dendrite size increases over the life of the battery, possibly related to the number of charge/discharge cycles of the battery. When dendrites form within a battery and grow larger over time, the dendrites tend to electrically short the internal components of the battery, resulting in battery failure.

Sustainable all-solid-state or semi-solid-state lithium ion batteries with the advent of lithium metal charge host electrodes that provide a stable charge host for lithium metal and promote a reversible ionization mechanism of lithium ions to lithium metal and vice versa. mass production in the consumer market can be achieved. Lithium metal maintains a theoretical energy capacity of 3850 mAh/g, while silicon-based lithium host electrode materials maintain a theoretical capacity of 4200 mA/g. For example, both of these materials acting as anodes have more than ten times the theoretical capacity of conventional graphite anode materials (372 mAh/g). However, these batteries still have the risk of cracking, leakage, and internal dendrite failure.

Thus, it has reduced charge time, higher storage capacity, and can be safely recharged over many charge/discharge life cycles while being less susceptible to cracking, leakage, and failure due to dendrite growth within the battery. There is a need for improved lithium-ion batteries for providing power supplies with reduced risk.

A rechargeable lithium-ion battery is provided that maintains a high capacity (ie, a capacity of 100 mAh/g or greater). In some embodiments, the rechargeable lithium ion batteries of the present application exhibit increased lifespan, increased number of charge/discharge cycles, reduced charge time (i.e., faster charge rate), volume expansion or deformation during cycling, or A reduction in both, a reduction in dendrite and crack formation, or a reduction in cell leakage due to cracking, or a combination thereof may also be exhibited.

A rechargeable lithium ion battery of the present application includes an electrolyte region located between a lithium-containing cathode material layer and an anode structure. The anode structure is of unitary construction (ie, monolithic structure) and includes non-porous regions and porous regions. The porous region comprises a top porous layer (Porous Region 1) having a first thickness and a first porosity and a second porosity greater than the first porosity and a thickness less than the first thickness. and a bottom porous layer (porous region 2) having a large second thickness. The bottom porous layer (ie porous region 2) underlies the top porous layer (ie porous region 1) and forms an interface with the non-porous region. Additionally, at least the upper portion of the non-porous region and the entire porous region are composed of silicon.

In another aspect of the present application, methods are provided for making the aforementioned anode structures for rechargeable lithium ion batteries. The method includes anodically etching a substrate including at least an upper region composed of p-doped silicon. In one embodiment, the relative depth, pore structure, and surface area of the anode structure, including porous regions 1 and 2, are controlled through the application conditions of the methods of the present application.

Another aspect of the present application presents a change in behavior to the anode structure for rechargeable batteries during the charge and discharge cycles of the battery. The anode and cell structures of the present application charge in a unique manner that exhibits reduced internal stress and reduced dendrite growth over cell life. While not wishing to be bound by any theory, it is believed that the charging operation of the present application contributes to reduced levels of internal cell stress and reduced cracking of the anode structure.

In yet another aspect of the present application, a combination of a cathode material comprising a particular grain size and grain boundary density or columnar microstructure and the present anode structure is used. The anode structures of the present application can sustainably plate lithium materials supplied from respective cathode materials of various sizes and masses. In particular, high capacity battery cells can be easily fabricated because the anode structure of the present application promotes apparent lithium plating during charging and lithium exfoliation during discharging.

1 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a first embodiment of the present application; FIG. FIG. 4 is a cross-sectional view of another exemplary rechargeable lithium-ion battery according to a second embodiment of the present application; FIG. 4 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a third embodiment of the present application; FIG. 4 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a fourth embodiment of the present application; FIG. 5 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a fifth embodiment of the present application; FIG. 6 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a sixth embodiment of the present application; FIG. 6 is a cross-sectional view of an exemplary rechargeable lithium-ion battery according to a sixth embodiment of the present application; 1 is a schematic diagram illustrating a method of forming an anode structure of the present application starting with a p-type crystalline silicon substrate before anodization and the anode structure after anodization; FIG. 1 is a cross-sectional transmission electron micrograph (TEM) showing a porous silicon anode structure showing two distinct porosity regions during anodization; FIG. (A) is a high resolution transmission electron micrograph (HRTEM) of the porous silicon anode structure showing the thickness of the porous region 1; (B) Secondary ion mass spectrometry of the first about 30 nm of a porous silicon anode structure corresponding to porous region 1 and the first about 90 nm of the same silicon anode structure corresponding to porous region 2 ( SIMS (secondary ion mass spectrometry) spectrum. (A) is a representation of a portion of a flow diagram showing the anode structure prior to operational use; (B) is a partial representation of a flow diagram showing the anode structure in operational use, where the seed layer forms during a charge cycle. (C) depicts a portion of a flow diagram showing the anode structure in operational use, where lithium plating occurs after continued charging. FIG. 4 shows SEM images of porous silicon anode structures after 5 cycles when using a liquid electrolyte. (A) is a partial flow diagram showing the anode structure in operational use, where lithium exfoliation occurs during discharge. (B) shows another SEM image of the porous silicon anode structure after about 250 cycles when using a liquid electrolyte. 10A shows SEM images for an all solid state lithium ion battery according to the present application comprising a structure similar to that shown in FIG. 1 in which the electrolyte region is a solid material, FIG. 10A before galvanostatic or potentiostatic induction charging or discharging; 1 is an SEM showing the structure of 10A-10B show SEM images for an all-solid-state lithium-ion battery according to the present application comprising a structure similar to that shown in FIG. 1 in which the electrolyte region is a solid material, FIG. 10B showing the structure after 6 charge and discharge cycles; Another SEM. Figures 10A and 10B show SEM images for an all-solid-state lithium-ion battery according to the present application comprising a structure similar to that shown in Figure 1 in which the electrolyte region is a solid material, Figure 10C showing the structure after 67 charge and discharge cycles; 4 is yet another SEM image; 1 is a flow chart illustrating one embodiment for fabricating the anode structure of the present application;

The present application will now be described in more detail with reference to the following discussion and drawings that accompany this application. It should be noted that the drawings of the present application are provided for illustrative purposes only and, as such, the drawings are not drawn to scale. Additionally, note that similar and corresponding components are indicated by similar reference numerals.

In the following description, numerous specific details are set forth, such as specific structures, components, materials, dimensions, processing steps, and techniques, in order to provide an understanding of various embodiments of the present application. there is However, given this disclosure, one skilled in the art will recognize that there are various alternative embodiments of this application that may be practiced without providing further specific details. In other cases, well-known structures or process steps may be used in combination with and/or with the inventive concepts. These structures and steps have not been described in detail to avoid obscuring the present application.

When a component, such as a layer, region, or substrate, is said to be “on” or “over” another component, that component is directly on top of the other component. and that there may be intervening components. In contrast, when a component is said to be "directly on" or "directly over" another component, there are no intervening components present. In addition, when a component is said to be “beneath” or “under” another component, that component is said to be “beneath” or “under” the other component. It will be understood that there may be directly present in the , or there may be intervening elements. In contrast, when a component is said to be "directly beneath" or "directly under" another component, there are no intervening components.

As described above, rechargeable lithium-ion batteries are provided that have high capacity (ie, capacities of 100 mAh/g or greater). In some embodiments, the rechargeable lithium ion batteries of the present application also exhibit increased longevity, or faster charging rates, or reduced volume expansion and/or deformation during charge/discharge cycling, or a combination thereof. may The rechargeable lithium ion batteries of the present application have an anode structure designed to increase the capacity and possibly also the charging rate of the battery (compared to conventional lithium ion batteries without the anode structure of the present application). include.

In one aspect of the present application, a rechargeable lithium ion battery is provided that includes a single-component anode structure. In particular, the anode structure includes a non-porous region and a porous region, the porous region comprising a top porous layer (Porous Region 1) having a first thickness and a first porosity, and a porous region having a first thickness. a bottom porous layer (porous region 2) having a second thickness greater than the thickness and a second porosity greater than the first porosity. The bottom porous layer (porous region 2) underlies the top porous layer (porous region 1) and forms an interface with the non-porous region. In the anode structure of the present application, at least the upper portion of the non-porous region and the entire porous region (including porous regions 1 and 2) are composed of silicon.

Also provided are methods of making the batteries, methods of using the batteries, structural features of the batteries in use, and battery structures having cathodes that enable fast charging rates. The anode structures of the present application can be used as components within a variety of conventional two-dimensional and three-dimensional battery configurations.

It is believed that the anode structure of the present application is stronger than those of the prior art because porous region 1 contains smaller pore sizes on average as compared to porous region 2 . In some embodiments, the anode structure comprising porous region 1 and porous region 2 as well as the larger non-porous region are mechanically, electrically, and chemically made of the same semiconducting material (i.e., anode The structure is a monolithic configuration). Thus, a mechanically stronger anode structure that is totally interconnected at the atomic level is provided, especially for silicon substrates in a crystalline configuration.

Additionally, it is believed that upon initial lithiation of the anode structure of the present application, the upper portion of porous region 2 becomes partially lithium-containing and the lower portion of porous region 2 is substantially devoid of lithium. . During this process a thin seed layer begins to form, the composition of this seed layer being composed of lithium rich material and silicon material, resulting in the formation of a planar lithium metal dense layer on top of the porous region 1. be done. This seed layer significantly reduces the migration of lithium ions deeper into the porous region 2 of the anode structure (and reduces the lithium ion concentration within the porous region 2). Thus, the formation of a thin seed layer on/in porous region 1 prevents further lithiation of porous region 2, resulting in deeper penetration of porous region 2 and non-porous regions. Suppression of further lithiation minimizes mechanical stress across the electrode.

As lithium migrates into the anode structure, the volumetric region where lithium and silicon of the anode structure combine expands. This volume can expand up to 400 percent of the original anode structure volume. Thus, the anode structure of the present application allows for reduced volume expansion during the lifetime (over charge/discharge cycles) of a rechargeable lithium-ion battery, resulting in reduced internal stresses throughout use of the battery.

Since lithium bonds with silicon in porous regions 1 and 2, the space within these porous regions accommodates the volume increase in these portions of the anode structure, further reducing mechanical stresses of charge and discharge.

In addition, as the battery charges/discharges over the life of the battery, the lithium maintains a seed layer of lithium combined with the silicon atoms present in the porous regions of the anode structure. This seed layer is sometimes referred to hereinafter as the lithium-containing seed layer. A small portion of lithium (less than 10% of the theoretical capacity) enters and penetrates porous region 1 and partially penetrates porous region 2 during seed layer formation. This process is relatively slow when not electrochemically induced, and the process is faster when induced at constant current or constant potential. As lithium accumulates on a previously deposited lithium-containing seed layer on/in the porous region 1, the lithium further forms a thin layer of metallic lithium on top of the porous region 1, The internal volume expands to physically close the pores within the porous region 1, and the lithium concentrations in the seed layer and metal layer provide an electrostatic barrier to further ingress of lithium into the anode structure of the present application. This minimizes the further migration of lithium deeper into the anode structure of the present application.

A fully formed seed layer minimizes additional lithium migration to the anode structure during subsequent charge/discharge cycles of the battery, thus volumetric expansion and contraction during charge/discharge cycles over most of the battery's life. and correspondingly reduce stress in the anode structure over the life of the cell.

Since a fully formed seed layer impedes migration of lithium ions to the anode structure, the following is observed. (i) lithium ions migrating from the cathode and electrolyte regions of the battery toward the anode structure during charge cycles increase the thickness of the lithium metal layer above the seed layer; Lithium ions migrating away from the anode structure from the cathode and electrolyte regions of the seed layer reduce the thickness of the lithium metal layer above the seed layer. Contrary to the prior art, however, the fully formed seed layer minimizes lithium diffusion during subsequent charge/discharge cycles of the battery. As a result of the anode structure of the present application, lithium is deposited primarily (e.g., via ion plating) on the seed layer, in a much reduced amount within the porous region 2, but in the non-porous regions of the anode structure. No significant amount is found in As a result, the very large volume of the anode structure, i.e., the non-porous regions of the anode structure, do not substantially absorb lithium during charge/discharge cycling and thus are observed in batteries not containing the anode structure of the present application. Does not undergo significant volumetric expansion and contraction leading to severe cracking and possible leaks.

It is assumed that the thin seed layer, once formed, does not change significantly during the charge/discharge cycles of the battery. The porosity of the porous region 1 is selected such that volumetric expansion of the top porous layer of the anode structure due to chemical bonding with lithium during seed layer formation does not lead to excessive stress in the porous region 1 .

The seed layer forms a smooth planar surface to which lithium ions are added (and removed) during the charge (discharge) cycles of operation while the thickness of the metallic lithium metal layer increases (decreases). Applicants have experimental evidence that a relatively smooth planar surface is maintained over the life of the cell, increasing the likelihood of inhibition of dendrite growth.

Referring now to FIG. 1, there is shown an exemplary rechargeable lithium ion battery according to the first embodiment of the present application. The exemplary rechargeable lithium-ion battery shown in FIG. 1 includes a battery material stack of anode current collector 10, anode structure 12, electrolyte region 18, lithium-containing cathode material layer 20, and cathode current collector 22. . Although the present application shows the anode current collector 10 as the bottommost material layer of the lithium ion battery of the present application, the present application also includes embodiments in which the cathode current collector 22 represents the bottommost material layer of the lithium ion battery of the present application. I assume. Other orientations for lithium-ion batteries are possible and are not excluded from this application.

In some embodiments, the rechargeable lithium ion batteries of the present application may be formed over a base substrate (not shown). When present, the base substrate may comprise any conventional material used as substrates for lithium ion batteries. In one embodiment, the base substrate may comprise a silicon-containing material or any other material with semiconductor properties, or both. The term "silicon-containing material" is used throughout this application to denote a material that contains silicon and has semiconducting properties. Examples of silicon-containing materials that can be used as base substrates for rechargeable lithium-ion batteries include silicon (Si), silicon-germanium alloys (SiGe), or carbon-doped silicon-based alloys. In one embodiment, the base substrate for rechargeable lithium-ion batteries is a bulk semiconductor substrate. By "bulk" is meant that the base substrate is composed entirely of at least one semiconductor material. In one example, the base substrate may be composed entirely of silicon, which may be monocrystalline. In some embodiments, the bulk semiconductor substrate may comprise a multi-layer semiconductor material stack comprising at least two different semiconductor materials. In one example, a multilayer semiconductor material stack may include a stack of Si and a silicon-germanium alloy in any order. In another embodiment, the multilayer semiconductor material may comprise stacks of Si and one or more silicon-based alloys, such as silicon-germanium or carbon-doped silicon-based alloys, in any order.

In other embodiments, base substrates for lithium ion batteries are, for example, aluminum (Al), aluminum alloys, titanium (Ti), tantalum (Ta), tungsten (W), or molybdenum (Mo), copper (Cu), nickel (Ni), platinum (Pt), or any alloy of these materials.

In some embodiments, the base substrate may have a non-textured (flat or planar) surface. The term "untextured surface" refers to a surface that is smooth and has a surface roughness on the order of less than 100 nm root mean square as measured by profilometry or atomic force microscopy. In yet another embodiment, the base substrate may have a textured surface. In such embodiments, the surface roughness of the textured substrate can range from 100 nm root mean square to 100 μm root mean square, also as determined by profilometry or atomic force microscopy. Texturing involves forming multiple etch masks (e.g., metals, insulators, or polymers) on the surface of an untextured substrate and using the multiple masks as etch masks to etch the untextured substrate. and removing the etch mask from the non-textured surface of the substrate. In some embodiments, the textured surface of the base substrate is composed of a plurality of high surface area three-dimensional features. In some embodiments, multiple metal masks are used, and these metal masks may be formed by depositing layers of metal material followed by annealing. Dewetting of the surface of the base substrate occurs by melting and balling up the layer of metal material during annealing.

Returning to FIG. 1, the anode current collector 10 that may be used in this application may be, for example, titanium (Ti), platinum (Pt), nickel (Ni), copper (Cu), aluminum (Al), or titanium nitride ( TiN) or any metal anode side electrode material. Anode collector 10 may comprise a layer of metallic anode electrode material or a material stack of at least two different metallic anode electrode materials. In one example, anode current collector 10 includes a stack of nickel (Ni) and copper (Cu) from bottom to top. Anode current collector 10 may have a thickness of 10 nm to 50 □m. Other thicknesses that are less than or greater than the aforementioned thickness values may also be used for the anode current collector 10 . Anode current collector 10 may be formed by deposition including, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), evaporation, sputtering, plating, or mechanically attached metal foils. It can be formed using a process. For improved contact resistance, it may be preferable to alloy the metal anode electrode material with the semiconductor material base. Alloying may be achieved by performing a siliconization process, as is known in the semiconductor industry.

An anode structure 12 is provided on the surface of the anode current collector 10 . The anode structure 12 includes a non-porous region 14 and a porous region (16, 17) having two layers with different porosities and thicknesses overlying the non-porous region 14 . The porous regions of the anode structure include a bottom porous layer 16 (ie, porous region 2) and a top porous layer 17 (ie, porous region 1). The non-porous region 14 and porous regions (16, 17) are of unitary construction. In one embodiment, the non-porous region 14 has a first surface in direct physical contact with the surface of the porous region 2 (i.e., the bottom porous layer 16) and the anode, opposite the first surface. It has a second surface in direct physical contact with the current collector 10 . Non-porous region 14 is the largest portion of the volume of anode structure 12 . In some embodiments, non-porous region 14 of anode structure 12 may have a thickness of 5 μm to 700 μm.

Porous region 1 (ie, top porous layer 17) has a first porosity and a first thickness, and porous region 2 (ie, bottom porous layer 16) has a second porosity and a second thickness. have a thickness; The porous region (16, 17) is designed. In one embodiment, the second porosity has an average pore opening greater than 3 nm and the second thickness is between 0.1 μm and 20 μm, while the first porosity is less than 3 nm. and the first thickness is 50 nm or less. While not wishing to be bound by any theory, it is believed that the inclusion of relatively small diameter pores in the porous region 1 facilitates the formation of a planarizing lithium-containing seed layer (see described in more detail below).

In this application, porosity may be a measure of the volume percentage of pores (the void space within the silicon) divided by the total volume of the porous regions (16, 17). Porosity can be measured, for example, by SEM, RBS, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Raman spectroscopy, gas adsorption on solids (porosimetry), mercury space-filling porosimetry, It may be measured using techniques well known to those skilled in the art, including density functional theory (DFT), or Brunauer-Emmett-Teller (BET), and the like.

It should be noted that the present application avoids porous regions (16, 17) with a porosity greater than 30% which, as in the prior art, tend to be brittle and may crack during use, thus causing battery failure.

While not wishing to be bound by any theory, the porous regions (16, 17) are divided into porous region 1 (i.e. top porous layer 17) and less porous region 2 (i.e. bottom porous layer 16). ) have a porosity such that there is sufficient open space within the porous regions (16, 17) to accommodate expansion (ie, increase) and/or deformation of both volumes. This is especially true in the formation of a lithium-containing seed layer, described in more detail hereinbelow, in porous region 1 (ie, top porous layer 17) during initial operation of a rechargeable lithium-ion battery.

Porous region 2 (ie, bottom porous layer 16) of anode structure 12 of the present application has a compressive stress of 0.02 percent to 0.035 percent. Compressive stress can be determined by X-ray diffraction or other optical or spectroscopic techniques.

As described above, porous region 1 (ie, top porous layer 17), porous region 2 (ie, bottom porous layer 16), and non-porous region 14 of anode structure 12 are of unitary construction. Non-porous region 14 and porous regions (16, 17) are thus electrically, chemically and mechanically part of the same anode structure. In some embodiments, porous region 1 (ie, top porous layer 17), porous region 2 (bottom porous layer 16), and non-porous region 14 are composed entirely of silicon. In this embodiment, anode structure 12 is fabricated by efficient method steps. Additionally, in embodiments in which the entire anode structure 12 is made of the same semiconductor material (i.e., Si), mechanical stress or additional electrical resistance within the anode structure 12 that may be caused by interfaces between different materials is reduced. not exist. In one example, anode structure 12, including non-porous region 14 and porous regions (16, 17), has a three-dimensional (3D) lattice framework composed of p-type crystalline silicon material. The term "p-type" refers to the addition of impurities to the native silicon material that result in valence electron depletion. Examples of p-type dopants, or impurities, in silicon-containing silicon materials include, but are not limited to, boron, aluminum, gallium, and indium.

In some embodiments, at least the upper portion of the non-porous region 14 of the anode structure 12 that forms the interface with the porous region 2 (i.e., the bottom porous layer 16) and all of the porous regions (16, 17) is composed of the same material, for example a p-type doped silicon material, whereas the lower portion of non-porous region 14 forms an interface with porous region 2 (i.e. bottom porous layer 16). The upper portion of the non-porous region 14 and the entire porous region (16, 17) of the anode structure 12 may be composed of a different semiconductor material. For example, the lower portion of the non-porous region 14 underlying the porous regions (16, 17) has a different dopant concentration than the original p-type doped silicon used to provide the anode structure 12. Doped silicon or silicon-germanium alloys containing less than 10 atomic percent germanium may be included.

In some embodiments, due to the simplicity and manufacturability of single crystal materials, at least the upper side of the non-porous region 14 of the anode structure 12 that forms the interface with the porous region 2 (i.e., the bottom porous layer 16) The silicon material that provides the parts and the entire porous regions (16, 17) is monocrystalline. In some embodiments, the cost of the process is reduced by using lower grade silicon and by adjusting the thickness of the silicon to simplify the crystal growth technique (similar to that observed in the solar industry). Can be reduced and controlled.

The anode structure 12 of the present application can be formed using an anode etching process defined in more detail hereinbelow (see, eg, FIG. 11).

The electrolyte that may be present in electrolyte region 18 may include any conventional electrolyte that may be used in rechargeable lithium ion batteries. the electrolyte may be a liquid electrolyte, a solid electrolyte, a gel-type electrolyte, a polymer electrolyte, a semi-solid electrolyte, an electrolyte that is originally liquid but is subsequently subjected to conditions that transform its phase into a solid or semi-solid, or any combination thereof; For example, it may be a combination of a liquid electrolyte and a solid electrolyte. In some embodiments, electrolyte region 18 is composed entirely of a solid electrolyte. In other embodiments, electrolyte region 18 may include a solid electrolyte and a liquid electrolyte. The electrolyte is between porous region 1 (ie, top porous layer 17 ) and lithium-containing cathode material layer 20 .

In some embodiments, electrolyte region 18 is a solid electrolyte composed of polymer-based or inorganic materials. In other embodiments, electrolyte region 18 is a solid electrolyte comprising a material that allows lithium ion conduction. Such materials may be electrically insulating and ionically conductive. Examples of materials that can be used as solid electrolytes are lithium phosphorous oxynitride (LiPON) or lithium phosphosilicate oxynitride (LiSiPON), thio-LiSiCoN electrolytes (e.g. Li ₂ SP ₂ S ₅ in any proportion ), Li ₁₀ SnP ₂ S ₁₂ , LiSiCoN-like electrolytes (eg, Li ₁₀ GeP ₂ S ₁₂ ), aldirodite electrolytes (eg, Li ₆ PS ₅ Br), garnet electrolytes (eg, Li _6.55 La ₃ Zr ₂ Ga _{0 .15} O ₁₂ ), NaSiCoN-like electrolytes (e.g. Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ ), Li nitride electrolytes (e.g. Li ₃ N), Li hydride electrolytes (e.g. Li ₂ NH), or perovskite electrolytes (eg, Li _0.34 La _0.51 TiO _2.94 ).

In embodiments in which a liquid electrolyte is used in electrolyte region 18, a separator, not shown, may be used. A separator may also be used in embodiments where there are two different electrolytes in electrolyte region 18 . When a separator is used, the separator can be a flexible porous material, gel, or cellulose, cellophane, polyvinyl acetate (PVA), PVA/cellulose blend, polyethylene (PE), polypropylene (PP). ), or one or more sheets composed of a mixture of PE and PP. Additionally, the separator may be composed of inorganic insulating nano/microparticles.

In embodiments in which a solid electrolyte layer is used as the electrolyte region 18, the solid electrolyte is deposited, for example, by sputtering, solution deposition, hot pressing, cold pressing, slurry casting followed by controlled temperature and pressure conditions, or plating. It may be formed using a deposition process. In one embodiment, the solid electrolyte is formed by sputtering using any conventional target source material with reactive or inert gases. For example, sputtering may be performed in the presence of at least a nitrogen-containing environment in forming the LiPON electrolyte. In some embodiments, the nitrogen-containing environment is used neat, ie, undiluted. In other embodiments, the nitrogen-containing environment may be diluted with inert gases such as helium (He), neon (Ne), argon (Ar), and mixtures thereof. The nitrogen ( _N2 ) content in the nitrogen-containing environment used is typically 10% to 100%, with 50% to 100% nitrogen content in the environment being more typical.

Lithium-containing cathode material layer 20 may comprise a lithium-containing material such as, for example, a lithium-based mixed oxide. Examples of lithium-based mixed oxides that can be used as the lithium-containing cathode material _layer 20 are lithium cobalt oxide ( _LiCoO2 ), lithium nickel oxide ( _LiNiO2 ), lithium manganese oxide ( _LiMn2O4 ), lithium vanadium pentoxide ( _LiV2O5 ), lithium nickel manganese cobalt ( _NMC ), nickel cobalt aluminum oxide (NCA), any combination of sulfur-based materials with lithium and other structural support elements such as iron, or lithium iron phosphate ( _LiFePO4 ), including but not limited to. The lithium-containing cathode material layer 20 may have a thickness of 10 nm to 50 μm. Other thicknesses less than or greater than the aforementioned thickness values may also be used for lithium-containing cathode material layer 20 .

In some embodiments, lithium-containing cathode material layer 20 may be formed using a deposition process such as, for example, sputtering, slurry casting, or plating. In one embodiment, lithium-containing cathode material layer 20 is formed by sputtering using any conventional precursor source material or combination of precursor source materials. In one example, a lithium precursor source material and a cobalt precursor source material are used in forming a lithium cobalt mixed oxide. Sputtering may be performed in a mixture of inert gas and oxygen. In such embodiments, the oxygen content of the inert gas/oxygen mixture may be from 0.1 atomic percent to 70 atomic percent, with the remainder of the mixture comprising inert gas. Examples of inert gases that can be used with oxygen include argon, helium, neon, nitrogen, or any combination thereof.

In some embodiments, the lithium-containing cathode material layer 20 may be formed by slurry casting, which includes electrochemically active [cathode materials, electronically conductive materials (e.g., carbon-based materials)] and inert ( binder material). The thickness of such layers may range from 5 μm to 500 μm. These slurries may also have an electrolyte component in the mixture along with the lithium-based salt(s).

Cathode current collector (or cathode side electrode) 22 comprises any metal cathode side electrode material such as, for example, titanium (Ti), platinum (Pt), nickel (Ni), aluminum (Al), or titanium nitride (TiN). It's okay. Cathode current collector 22 may comprise a single layer of metallic cathode electrode material or a material stack comprising at least two different metallic cathode electrode materials. In one example, cathode current collector 22 includes a stack of titanium (Ti), platinum (Pt), and titanium (Ti) from bottom to top. In one embodiment, the metal electrode material that provides cathode current collector 22 may be the same as the metal electrode material that provides anode current collector 10 . In another embodiment, the metal electrode material that provides cathode current collector 22 may be different than the metal electrode material that provides anode current collector 10 . Cathode current collector 22 may have a thickness within the ranges described above for anode current collector 10 . Cathode current collector 22 may be formed using one of the deposition processes described above for forming anode current collector 10 . For slurry-based cathode materials, metal foil may be used during the casting process.

Referring now to Figure 2, there is shown another exemplary rechargeable lithium-ion battery according to the second embodiment of the present application. The exemplary lithium-ion battery shown in FIG. It is similar to the rechargeable lithium-ion battery stack shown in FIG. Specifically, the exemplary rechargeable lithium-ion battery shown in FIG. 2 includes the anode current collector 10 defined above, the anode structure 12 defined above, and the , the electrolyte region 18 defined above, the lithium-containing cathode material layer 20 defined above, and the cathode current collector 22 defined above. The battery material stack shown in FIG. 2 may have other orientations in addition to those shown in FIG. For example, the battery material stack may be flipped 180°.

An interfacial additive (eg, dielectric material, etc.) layer 24 is present on the exposed surface of porous region 1 (ie, top porous layer 17) of anode structure 12 . Layer 24 may be a single layer structure or a multi-layer structure. The interfacial additive material layer 24 may comprise any interfacial additive material layer such as, for example, a carbon-based material, or an oxide of gold or a dielectric material, such as aluminum oxide. The interfacial additive material is any combination of electrically insulating and Li-ion ion-conducting components such as, but not limited to, LiNbO ₃ , LiZrO ₂ , Li ₄ SiO ₄ , or Li ₃ PO ₄ . It may be a mixture with The interface additive material layer 24 may have a thickness of 1 nm to 50 nm. Interface additive material layer 24 may be formed using a deposition process including, for example, chemical vapor deposition, plasma enhanced chemical vapor deposition, or atomic layer deposition. The interfacial additive material layer 24 can enable a high degree of chemical and physical interconnectivity between the electrolyte and electrode layers under repeated electrochemical conditioning. The ability of the interfacial additive material layer 24 to maintain structural rigidity to interfacial overlap allows for high ionic conductivity and reduces the internal resistance of the cell. In addition, the interface additive material layer 24 can provide electrical isolation at the interface, preventing cell leakage or shorting through spatial control of electrically conductive components within the battery. The interfacial additive material layer 24 described above can be continuous or patterned.

Referring now to Figure 3, there is shown another exemplary rechargeable lithium-ion battery according to the third embodiment of the present application. The exemplary rechargeable lithium ion battery shown in FIG. 3 is shown in FIG. 1, except that interfacial additive material layer 26 is disposed between electrolyte region 18 and lithium-containing cathode material layer 20. Similar to rechargeable lithium-ion battery stacks. Specifically, the exemplary rechargeable lithium-ion battery shown in FIG. 3 includes the anode current collector 10 defined above, the anode structure 12 defined above, the electrolyte region 18 defined above, It comprises a battery material stack of an interfacial additive material layer 26 defined in more detail herein below, a lithium-containing cathode material layer 20 defined above, and a cathode current collector 22 defined above. The battery material stack shown in FIG. 3 may have other orientations in addition to those shown in FIG. For example, the battery material stack may be flipped 180°.

Interface additive material layer 26 may include any of the interface additive materials described above for interface additive material layer 24 . The interfacial additive material layer 26 may have a thickness of 1 nm to 20 nm to minimize the increase in cell internal resistance. Interface additive material layer 26 may be formed using a deposition process including, for example, chemical vapor deposition, plasma enhanced chemical vapor deposition, or atomic layer deposition. The ability of the interfacial additive material layer 26 to maintain structural rigidity to interfacial overlap allows for high ionic conductivity and reduces the internal resistance of the cell. In addition, the interface additive material layer 26 can provide electrical isolation at the interface, preventing cell leakage or shorting through spatial control of electrically conductive components within the battery.

Referring now to Figure 4, an exemplary rechargeable lithium ion battery according to a fourth embodiment of the present application is shown. The exemplary rechargeable lithium ion battery shown in FIG. 4 has an interfacial additive material layer 24 disposed between porous region 1 (i.e., top porous layer 17) of anode structure 12 and electrolyte region 18, and the electrolyte It is similar to the rechargeable lithium ion battery stack shown in FIG. Specifically, the exemplary rechargeable lithium-ion battery shown in FIG. 4 includes the anode current collector 10 defined above, the anode structure 12 defined above, and the interfacial dielectric material layer 24 defined above. and the electrolyte region 18 defined above, the interfacial dielectric material layer 26 defined above, the lithium-containing cathode material layer 20 defined above, and the cathode current collector 22 defined above. Including stack. The battery material stack shown in FIG. 4 may have other orientations in addition to those shown in FIG. For example, the battery material stack may be flipped 180°.

Referring now to FIG. 5, there is shown an exemplary rechargeable lithium ion battery according to the fifth embodiment of the present application. The exemplary rechargeable lithium ion battery shown in FIG. 5 is shown in FIG. 1, except that the porous regions of anode structure 12 (including porous region 1 and porous region 2) are patterned. It is similar to the rechargeable lithium-ion battery stack that is commonly used. A patterned porous region that includes both porous regions 1 and 2 (not individually shown) is designated as element 16P in FIG. 5 of this application. Specifically, the exemplary lithium ion battery shown in FIG. 5 comprises the anode current collector 10 defined above and the patterned porous region 16P defined above (including porous regions 1 and 2). , an electrolyte region 18 as defined above, a lithium-containing cathode material layer 20 as defined above, and a cathode current collector 22 as defined above. The battery material stack shown in FIG. 5 may have other orientations in addition to those shown in FIG. For example, the battery material stack may be flipped 180°.

Interfacial additive material layer 24 may be formed between patterned porous region 16P and electrolyte region 18, or interfacial additive material layer 26 may be formed between electrolyte region 18 and lithium-containing cathode material layer 20. or both. Patterning of the porous regions (including porous regions 1 and 2) is done using conventional patterning techniques including, for example, lithography and etching, possibly in combination with mechanical grinding/polishing, doping, and the like. good too. In some embodiments, patterning of the porous regions (16, 17) may be done by simple selective doping of silicon, such as by ion implantation, epi, or thermal doping. Patterned porous regions 16P (collectively comprising porous regions 1 and 2) may provide a means to further increase the capacity and dynamic (power) capabilities of the anode structure 12 of the present application. . Patterned porous regions 16P (which collectively include porous regions 1 and 2) may also provide faster charging rates.

6A-6B, an exemplary rechargeable lithium ion battery according to a sixth embodiment of the present application is shown. The exemplary rechargeable lithium-ion battery shown in FIGS. 6A and 6B has the porous regions of anode structure 12 (including porous region 1 and porous region 2) patterned and a layer of lithium-containing cathode material. Similar to the lithium-ion battery stack shown in FIG. 1, except that 20 is also patterned. The patterned porous regions (including porous regions 1 and 2) are designated element 16P in FIGS. 6A-6B of this application, and the patterned lithium-containing cathode material layer is shown in FIG. Denoted as element 20P in ˜6B. Specifically, the exemplary lithium-ion battery shown in FIGS. ), the electrolyte region 18 defined above, the patterned lithium-containing cathode material layer 20P defined above, and the cathode current collector 22 defined above. . The battery material stack shown in FIGS. 6A-6B may have other orientations in addition to those shown in FIGS. 6A-6B. For example, the battery material stack may be flipped 180°.

In one embodiment, as shown in FIG. 6A, patterned battery material stack components 16P and 20P face each other, e.g., the higher area (lower area) of each component is Facing each other at the same lateral position of the cell. Alternatively, patterned battery material stack components 16P and 20P may be complementary shapes that fit like a keyhole and key as shown in FIG. 6B. In this embodiment, the thickness of the electrolyte (the electrolyte fills all the spaces between cell components 16P and 20P) as well as the proximity of the patterned electrodes with respect to each other determines the particular proximity of the counter electrodes with respect to each other. can be controlled by aligning with the height. Interfacial additive material layer 24 may be formed between patterned region 16P (collectively comprising porous regions 1 and 2) and electrolyte region 18, or electrolyte region 18 and a patterned lithium-containing cathode material layer. An interfacial additive material layer 26 may be formed between 20P, or both.

Patterning of the lithium-containing cathode material layer 20P may be performed using conventional patterning techniques including, for example, lithography and etching, or using a lift-off process. Patterned lithium-containing cathode material layer 20P may be complementary or non-complementary with respect to patterned porous region 16P. The patterned lithium-containing cathode material layer 20P may provide further increases in the capacity and dynamic charge/discharge capabilities of the lithium-ion batteries of the present application. Collectively, patterned porous region 16P (which collectively includes porous regions 1 and 2) and patterned lithium-containing cathode material layer 20P provide maximized battery capacity and possibly speed of battery charging. It may also be increased, which means that the pattern dimension will eventually increase the volume of space between patterned porous region 16P (which collectively includes porous regions 1 and 2) and patterned lithium-containing cathode material layer 20P. This is because, along with the fixed proximity, the thickness, density, and other physical properties of the electrolyte region 18 can be influenced to define them, thereby directly affecting the ion-electron transfer characteristics throughout the cell stack.

Referring now to FIG. 7A, there is shown a schematic diagram illustrating the overall process of using crystalline p-type silicon material 50 for the anodic etching method described herein. In particular, the process begins by providing a crystalline p-type silicon material 50, which is then anodic etched to form Porous Region 1 (PR1) (i.e., top porous layer 17) and porous layer 17). An anode structure is provided that includes region 2 (PR2) (ie, the bottom porous layer 16), as well as the unetched portion of the original crystalline p-type silicon substrate underlying the two porous regions. The unetched portions of the original substrate define non-porous regions 14 of the silicon substrate. In this figure, non-porous region 14 is also indicated as element 50S. Note that non-porous region 50S has the same characteristics as non-porous region 14 described above.

FIG. 7B is a transmission electron micrograph (TEM) (by cross-section) of an experimentally fabricated porous silicon substrate such as that shown in FIG. 7A. This TEM micrograph clearly shows the two porous regions PR1 (ie, top porous layer 17) and PR2 (ie, bottom porous layer 16) shown in FIG. 7A, where porous region 1 is about Porous region 2 is considerably thicker than porous region 1, having a thickness of the order of 30 nm.

FIG. 8(A) is a high resolution transmission electron micrograph of one embodiment of the porous silicon material shown in FIG. 7A herein. The scale line in this figure indicates that the total thickness of porous region 1 is about 29 nm. FIG. 8(B) is a secondary ion mass spectrometry (SIMS) profile of the porous silicon material shown in FIG. 8(A). This SIMS profile shows relatively low concentrations of carbon, oxygen, and fluorine elements in the first 30 nm of the porous silicon material, which is directly related to porous region 1 (connected by double-headed arrows 8(A) and 8(B)).

9A-9C, a sequence of steps is shown as a flow chart to prepare porous silicon electrodes (ie, non-porous region 50S, porous region 2 (PR2), and porous region 1 (PR1)). ) and the operation of charge storage through the electrode material when liquid-based electrolytes are used are shown with the seed layer 52 during charge and discharge cycles, plus 5 cycles (Fig. 9B) and SEM images of the porous silicon electrode at about 250 cycles (FIG. 9C(B)) are shown. In particular, FIG. 9A shows the porous silicon electrode described and shown in FIG. 7A prior to incorporation into an electrochemical energy storage cell. The porous silicon electrode includes non-porous region 50S, porous region 2 (PR2), and porous region 1 (PR1). FIG. 9A(B) shows the initial lithiation process of a porous silicon electrode when incorporated into a Li-ion electrochemical energy storage cell. upon initial exposure of the porous silicon electrode to a lithium ion-containing electrolyte, or during the first period of electrochemical lithiation of the porous silicon electrode, or during initial charging of the porous silicon electrode, or a combination thereof. , planar lithium-containing seed layer 52 formation occurs. As shown, a lithium-containing seed layer 52 overlies porous region 1, and in some embodiments a portion of seed layer 52 may extend into the upper portion of porous region 2. . The topmost surface of seed layer 52 is typically flat or planar. FIG. 9A(C) is a schematic illustration of planar lithium plating that occurs during the charging process. In FIG. 9A(C), element 54 indicates the planar lithium layer formed during this operational step. It should be noted that when the battery reaches full charge, the thickness of the plated lithium metal 54 on the seed layer 52 is determined by the operating voltage range of the lithium deintercalated from the lithium-containing cathode material layer and transferred from the electrolyte. Proportional to quantity.

FIG. 9B is a scanning electron microscope cross-sectional view of the porous silicon electrode showing the plating phenomenon shown in FIG. being filmed. In the charged state, lithium ingress penetrates through porous region 1, but is observed only in the top portion of porous region 2, which causes some cracking in the upper portion of porous region 2. FIG. 9C(A) illustrates the lithium deplating that occurs during the discharge process, where a portion of the lithium metal 54 remains irreversibly plated on top of the seed layer 52 . Due to the discharge, the thickness of the remaining portion of the plated lithium metal 54 is substantially less than the thickness of the planar lithium layer 54 formed in the charged state shown in FIG. 9A(C). It should be noted that the thickness of the layer of lithium metal relatively decreases as the battery approaches a sustainable discharge state, as determined by the working voltage range. FIG. 9C(B) is a scanning electron microscope cross-sectional view of the porous silicon electrode in a discharged state that has been charged and discharged five times corresponding to FIG. 9C(A). In one embodiment, the working voltage range is 4.2V to 3.0V. In one embodiment, the lithium-containing cathode material layer is lithium cobalt oxide. The seed layer formation and lithium metal plating that occurs during charging and the subsequent deplating of lithium metal that occurs during discharging may be used in solid or liquid electrolytes, or any other type of electrolyte referred to herein. observed for lithium-ion batteries containing

In some embodiments, the rechargeable lithium ion batteries of the present application can be charged and discharged for more than 200 cycles when using sustainable working voltages such as those described above. After 200 charge and discharge cycles, the surface of the plated lithium metal is nominally continuously planar on average.

10A-10C, actual SEM images are shown for an all-solid-state lithium-ion battery comprising a structure similar to that shown in FIG. 1 according to the present application, where electrolyte region 18 is, for example, LiPON is a solid material. This structure also includes the anode structure 12 shown in FIG. 1 or FIG. 9A. In particular, FIG. 10A is an SEM of the structure before galvanostatic or potentiostatic induction charge or discharge, FIG. 10B is another SEM of the structure after 6 charge and discharge cycles, and FIG. 10C is 67 charge and discharge. FIG. 11 is yet another SEM image of the structure after cycling; FIG.

The SEM of FIG. 10A is a cross-sectional SEM image of an all-solid-state battery prior to galvanostatic or potentiostatic induced electrochemical charging or discharging, showing porous silicon electrodes (i.e., non-porous regions (not shown) and An anode structure comprising porous region 2 (PR2) and planar porous region 1 (PR1)) is shown, where solid electrolyte region 18 resides above porous region 1 (PR1). FIG. 10B is a cross-sectional SEM image of the all-solid-state cell shown in FIG. 10A after 6 galvanostatic inductive charge and discharge cycles, where from bottom to top porous region 2 (PR2), lithium-containing seed layer 52; Porous Region 1 (PR1) containing is observed. In particular, an off-white feature originating from the porous region 1 (PR1)/solid electrolyte region 18 interface is clearly observed, and this feature constitutes the lithium-containing seed layer 52 or It is believed to represent the reaction of air with the lithium-rich material, which constitutes the plated lithium metal present on the lithium-containing seed layer 52 formed at 100° C., or both. FIG. 10C is a cross-sectional SEM image of the all-solid-state cell shown in FIG. 10A after 67 galvanostatic inductive charge and discharge cycles, where from bottom to top substantially pristine porous Region 2 (PR2); Partially lithiated Porous Region 2 (PR2) and planar formation of lithium metal-containing dendrite features mixed with solid electrolyte material in Porous Region 1 (PR1) and electrolyte region 18 are observed. be. upon initial exposure of the porous silicon electrode to a lithium ion-containing electrolyte, or during the first period of electrochemical lithiation of the porous silicon electrode, or during initial charging of the porous silicon electrode, or a combination thereof. , planar lithium-containing seed layer 52 formation occurs. As shown, the lithium-containing seed layer 52 is located within the porous region 1 area, and a portion of the seed layer 52 may extend into the upper portion of porous region 2 . As observed in FIGS. 10A and 10B, the topmost surface of seed layer 52 is typically flat or planar, and prior to cycling, PR1 and seed layer 52 are in intimate planar contact with electrolyte region 18. are in contact with each other. This planar lithium metal-containing seed layer is believed to act as a host or nucleation site for subsequent plating/stripping of lithium metal, respectively, during subsequent charge/discharge cycles. After 6 charge/discharge cycles, the lithium-rich material forming the seed layer and/or the lithium metal plating seed layer self-locks upon breaking and cutting the cell to obtain the SEM image of FIG. 10B. changes from the flat state This respective lithium metal-containing layer is now observed to react with ambient air chemicals to form an off-white feature that emerges/generates from the PR1/solid electrolyte region 18 interface region. In FIG. 10C, after 56 charge/discharge cycles, a substantially pristine Porous Region 2 (PR2) area is observed over which a partially lithiated Porous Region 2 is observed (PR2). , the formation of about 183 nm lithium-rich dendrite-type planar layer is observed in the porous region 1 (PR1) area thereon, on which the LiPON electrolyte area is observed. In particular, lithium-rich dendrite features formed planarly in/on the Porous Region 1 (PR1) region and remained stable upon cell fracture and disconnection after 67 charge/discharge cycles. , the observation that there is intimate and continuous contact between the solid electrolyte region 18 and the lithium metal-rich dendrite features in/on the porous region 1 (PR1) section, the liquid In addition to stable lithium metal host porous silicon anode containing batteries containing electrolyte, the present invention demonstrates high effectiveness as a stable lithium metal host porous silicon anode in all-solid-state batteries.

In some embodiments, during multiple charge/discharge cycles, in addition to dendrite formation at the lithium metal/electrolyte interface, , a unique dendrite formation occurs.

The rechargeable lithium-ion batteries shown in FIGS. 1-5, 6A, and 6B may have any size and/or shape. An example range includes any value from 10 μm to less than 1 mm (lesser) and greater than 1 mm. In one example, the size of a rechargeable lithium-ion battery may be 100 μm×100 μm×100 μm. In another example, the size of a rechargeable lithium-ion battery may be 50mm x 50mm x 5mm. In some embodiments where a semiconductor-based substrate is present, the rechargeable lithium-ion batteries shown in FIGS. It may be integrated with semiconductor devices, including devices, central processing units, silicon-based device structures, and the like. The batteries that power the semiconductor devices may be on either the same side or the opposite side of the semiconductor substrate.

Integration may be done in two ways. 1) conventionally by preliminary patterning, lithography, etching of the semiconductor substrate prior to anodization and fabrication of the porous semiconductor regions, or 2) selective doping, e.g. ion implantation, followed by e.g. By thermal annealing such as lamp or laser annealing, or by selective epitaxial growth or the like. The devices may be on the same original semiconductor substrate, integrated with the same original semiconductor substrate, or on adjacent semiconductor substrates within a given working proximity (same both sides are possible).

The method of fabricating the anode structure 12 of the present application will now be considered in more detail. The method of the present application provides the following. 1) "grow" or create or etch a porous semiconductor region connected to a non-porous semiconductor region (eg, monocrystalline silicon material, etc.), which can then be integrated into/with other silicon-based technologies. 2) The successful integration and use of liquid, solid, and semi-solid electrolytes and their high performance capabilities in rechargeable batteries (which are versatile with any electrolyte). In addition, 3) the ability to control the thickness of the solid electrolyte in the nanometer range due to the mirror-like smooth surface of the starting silicon substrate allows for a high degree of control over battery performance, charging rate, and ion mobility, and physical compatible with the deposited electrolyte.

In particular, the anode structure 12 of the present application can be fabricated using an anodization process in which a substrate containing at least the upper region of p-type silicon material is immersed in a solution of concentrated HF (49%) while A current is applied with platinum as the anode and the substrate as the cathode. The anodization process is performed using a constant current source operating at a current density of 0.05 mA/ ^cm2 to 150 mA/ ^cm2 , where mA is milliamperes. In some examples, the current density is 1 mA/ ^cm2 , 2 mA/ ^cm2 , 5 mA/ ^cm2 , 50 mA/ ^cm2 , or 100 mA/ ^cm2 . In preferred embodiments, the current density is between 1 mA/cm ² and 10 mA/cm ² . Current densities may be applied for 1 second to 5 hours. In some examples, the current density may be applied for 5 seconds, 30 seconds, 20 minutes, 1 hour, or 3 hours. In one embodiment, the current density may be applied for 10 seconds to 1200 seconds, specifically for doping levels in the range 10 ¹⁹ cm ³ . The anodization process is typically performed at nominal room temperature (20° C. to 30° C.) or slightly elevated from room temperature. Following the anodization process, the structure shown in Figure 7B is typically rinsed with deionized water and then dried.

In some embodiments, after anodization, anode structure 12 may be cut to desired dimensions before use. In some embodiments, the anode structure 12 may be placed over, and optionally bonded to, the anode current collector 10 defined above, after which various other components of the lithium ion battery may be formed. may be formed. In other embodiments, the anode structure 12 is placed over, optionally over, the electrolyte region 18 of a prefabricated battery material stack that also includes a cathode region that includes a lithium-containing cathode material layer 20 and a cathode current collector 22 . may be coupled to

Referring now to Figure 11, a flow chart illustrating one embodiment for fabricating the anode structure 12 of the present application is shown. In particular, anode structure 12, including porous region 1 and porous region 2 and non-porous region 14 (or 50S) discussed above, can be formed using the processing steps shown in FIG. In one embodiment, the substrate 12 may consist entirely of p-type doped crystalline silicon material, while in other embodiments, another silicon material or germanium (doped silicon material) underlies the p-type doped silicon material. or undoped) may be present. The method consists of a first step, in which a p-doped silicon substrate is treated with a mixture of ammonium hydroxide, deionized water and hydrogen peroxide (5:1:1 v/v) at 60°C to 80°C. It may include step 1 (70) of washing for about 10 minutes. Next, in step two (72), the cleaned p-doped silicon substrate is immersed in 49% hydrofluoric acid, after which a current is applied to it to initiate electrochemical anodization (i.e. anodizing etching). be. In one embodiment, the applied current is constant current in the range of 1 mA/cm ² to 10 mA/cm ² . In step three (74), the anodizing etch is continued using the following electrochemical anodizing conditions. 10 s to 2000 s at nominal room temperature (20° C. to 30° C.) and ≤5 mA/cm ² . After etching, in step four (76) the etched silicon substrate is rinsed with deionized water and then dried. The anodization process defined in step 3 transforms the upper portion of the substrate containing p-doped silicon into porous Regions 1 and 2, while the underlying substrate remains unaffected by the anodization process as described above. A non-porous region 14 (or 50S) is formed.

In any of the above-described embodiments, as shown in FIGS. 1-5, 6A, and 6B, the lithium-containing cathode material layer 20 has a grain size of less than 100 nm and a grain boundary of 10 ¹⁰ cm ⁻² or more. and density. In some embodiments, the particle size of the individual particles that make up the lithium-containing cathode material layer 20 is from 1 nm to less than 100 nm. In some embodiments, the density of boundaries can be from 10 ¹⁰ cm ⁻² to 10 ¹⁴ cm ⁻² . The term "grain boundary" is defined herein as the interface between two grains of a material. The grain boundaries are somewhat randomly oriented within the lithium-containing cathode material layer 20 . Some of the grain boundaries completely separate the cathode material such that one end of the grain boundary is at the bottommost surface of the cathode material and another end of the grain boundary is located at the topmost portion of the cathode material. May extend through. In this embodiment, the grain boundaries are not oriented perpendicular to the top and bottom surfaces of the lithium-containing cathode material layer 20 .

In any of the above-described embodiments as shown in FIGS. 1-5, 6A, and 6B, the lithium-containing cathode material layer 20 may have a columnar microstructure with columnar grain boundaries. good. The columnar grain boundaries are oriented perpendicular to the topmost and bottommost surfaces of the lithium-containing cathode material layer 20 . In such embodiments, the lithium-containing cathode material layer 20 has a plurality of fin-like structures within the cathode material. A lithium-containing cathode material layer 20 having a columnar microstructure has a grain size of less than 100 nm and a density of columnar grain boundaries of 10 ¹⁰ cm ^{−2 or} more. In some embodiments, the particle size of the individual particles that make up the lithium-containing cathode material layer 20 is from 1 nm to less than 100 nm. In some embodiments, the density of columnar grain boundaries can be between 10 ¹⁰ and 10 ¹⁴ cm ⁻² . In one embodiment, the electrically conductive cathode material is a lithium-containing material as defined above.

^For example, in ^rechargeable battery material stacks such as those shown in FIGS. The presence of the lithium-containing cathode material layer 20 containing particles with a density or the lithium-containing cathode material layer 20 having a columnar microstructure allows the rapid and substantially or totally vertical ions, i.e. Li ions, to Transportation is facilitated, which can result in fast charging batteries.

An anode structure 12 and a lithium-containing cathode material layer 20 containing particles having a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or a lithium-containing cathode material layer 20 having a columnar microstructure. may exhibit a charge rate of 5C or greater, where C is the total battery capacity per hour. In some embodiments, the anode structure 12 and the lithium-containing cathode material layer 20 containing particles having a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or a columnar microstructure. The charge rate of the battery including the lithium-containing cathode material layer 20 with a charge rate can be from 5C to 1000C or higher. In addition, an anode structure 12 and a lithium-containing cathode material layer 20 containing particles having a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or a lithium-containing cathode having a columnar microstructure. A rechargeable battery including material layer 20 may have a capacity of 100 mAh/gm cathode material or greater.

The lithium-containing cathode material layer 20 containing grains with a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or the lithium-containing cathode material layer 20 having a columnar microstructure can be obtained by a sputtering process. may be formed using In some embodiments, no subsequent annealing is performed after sputtering the cathode material. The sputtered cathode material without annealing provides a lithium-containing cathode material layer 20 containing grains with a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or greater. In other embodiments, sputtering of the cathode material may be followed by annealing to provide a lithium-containing cathode material layer 20 having a columnar microstructure. The anneal is performed at a temperature below 300° C. in order to preserve the charge rate greater than 5C. In one embodiment, sputtering may include the use of any precursor source material or combination of precursor source materials. In one example, a lithium precursor source material and a cobalt precursor source material are used in forming a lithium cobalt mixed oxide. Sputtering may be performed in a mixture of inert gas and oxygen. In such embodiments, the oxygen content of the inert gas/oxygen mixture may be from 0.1 atomic percent to 70 atomic percent, with the remainder of the mixture comprising inert gas. Examples of inert gases that can be used include argon, helium, neon, nitrogen, or any combination thereof.

The lithium-containing cathode material layer 20 containing particles with a grain size of less than 100 nm and a density of grain boundaries of 10 ¹⁰ cm ⁻² or more, or the lithium-containing cathode material layer 20 having a columnar microstructure, is between 10 nm and 20 μm. may have a thickness of For a lithium-containing cathode material layer 20 containing particles having a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or a lithium-containing cathode material layer 20 having a columnar microstructure, the aforementioned Other thicknesses smaller or larger than the thickness value of may also be used. A thick lithium-containing cathode material layer 20 containing particles with a grain size of less than 100 nm and a density of grain boundaries of 10 ¹⁰ cm ⁻² or more, or a lithium-containing cathode material layer 20 with a columnar microstructure, has been found to be useful in batteries. Improved battery capacity can be provided due to the larger area or volume for storing charge.

Although the present application has been particularly shown and described with respect to its preferred embodiments, it will be understood by those skilled in the art that the foregoing and other changes in form and detail may be made without departing from the spirit and scope of the present application. would It is therefore intended that the present application be not limited to the precise forms and details described and illustrated, but fall within the scope of the appended claims.

Claims (45)

a lithium-containing cathode material layer;
An anode structure comprising a non -porous region and a porous region, wherein the porous region is positioned below the top porous layer having a first thickness and a first porosity. and a bottom porous layer forming an interface with said non-porous region, wherein at least an upper portion of said non-porous region and the entirety of said porous region are of unitary construction and composed of silicon. wherein said bottom porous layer has a second thickness greater than said first thickness and a second porosity greater than said first porosity;
A battery comprising an electrolyte region located between said top porous layer of said anode structure and said lithium-containing cathode material layer. 2. The battery of claim 1, wherein said top porous layer, said bottom porous layer, and said non-porous region are composed entirely of silicon. 3. The battery of claim 2, wherein said silicon is monocrystalline. 2. The cell of claim 1, wherein the lower portion of said non-porous region is composed of doped silicon or a doped silicon-germanium alloy having a germanium content of less than 10 atomic percent. 2. The cell of claim 1, wherein said top porous layer has an average pore opening of less than 3 nm and said bottom porous layer has an average pore opening of greater than 3 nm. 2. The battery of claim 1, wherein said first thickness of said top porous layer is 50 nm or less. 2. The battery of claim 1, wherein said second thickness of said bottom porous layer is from 0.1 [mu]m to 20 [mu]m. 2. The battery of claim 1, wherein the non-porous region is composed of p-doped silicon that is single crystal. 2. The battery of claim 1, wherein said non-porous region and said porous region are composed entirely of p-type doped silicon. 2. The cell of claim 1, wherein said silicon is p-doped silicon having a p-type dopant concentration of 10 ¹⁹ cm ⁻³ . 2. The battery of claim 1, wherein said silicon is boron doped silicon. 2. The cell of claim 1, further comprising an anode current collector in contact with the surface of said non-porous region of said anode structure. 2. The battery of claim 1, further comprising a cathode current collector electrode in contact with the surface of said lithium-containing cathode material layer. 11. The electrolyte region comprises a solid electrolyte, a liquid electrolyte, a semi-solid electrolyte, an originally liquid-to-solid electrolyte, a gel electrolyte, a polymer-containing electrolyte, a composite cathode/electrolyte combination, or any combination thereof. batteries described in . 2. The battery of claim 1, wherein the electrolyte region is composed entirely of a solid electrolyte. 2. The battery of claim 1, further comprising an interfacial additive material layer positioned between said top porous layer of said anode structure and said electrolyte region. 2. The battery of claim 1, further comprising an interfacial additive material layer located between said electrolyte and said lithium-containing cathode material layer. a first interfacial additive material layer located between the top porous layer and the electrolyte region of the anode structure, and a second interfacial additive material located between the electrolyte and the lithium-containing cathode material layer. 3. The battery of claim 1, further comprising a material layer. 2. The battery of claim 1, wherein said porous region comprising said top and bottom porous layers is patterned. 20. The battery of claim 19, wherein said lithium-containing cathode material layer is patterned. 2. The battery of claim 1, wherein the porous regions are located on the top, bottom, or sides of any three-dimensional structure. The lithium-containing cathode material layer is selected from a lithium-containing material containing particles having a grain size of less than 100 nm and a grain boundary density of 10 ¹⁰ cm ⁻² or more, or a lithium-containing material having a columnar microstructure. The battery of claim 1, wherein 16. The battery of claim 15, wherein said battery further comprises a seed layer located on the surface of said top porous layer of said anode structure, said seed layer being a planar conformal lithium-containing material. A method of making a lithium battery anode structure, the method comprising:
immersing a substrate, including at least an upper portion composed of p-doped silicon, in concentrated hydrogen fluoride using anodization equipment;
applying a current to the anodizing equipment;
and electrochemically anodizing the substrate, wherein the anodizing step provides a structure including a non- porous region and a porous region, the porous region having a first thickness and a first thickness. a top porous layer having a porosity of 1 and a bottom porous layer underlying said top porous layer and forming an interface with said non-porous region, at least above said non-porous region The portion and the entirety of the porous region are of unitary construction and are composed of silicon, and the bottom porous layer has a second thickness greater than the first thickness and the first porosity. and a second porosity greater than. 25. The method of Claim 24, further comprising cleaning the substrate prior to the soaking step. 25. The method of claim 24, further comprising rinsing the structure with deionized water and drying after the anodizing step. 25. The method of claim 24, wherein the substrate consists entirely of p-doped silicon. 28. The method of claim 27, wherein said p-doped silicon is single crystal. The washing step includes adding a mixture of deionized water, ammonium hydroxide and hydrogen peroxide (5:1:1 by volume) at a temperature of 60° C. to 80° C. for a period of 5 minutes to 30 minutes. 26. The method of claim 25, performed by rinsing with deionized water after use. 25. The method of claim 24, wherein the concentrated hydrogen fluoride is a 49 wt % hydrofluoric acid solution. 25. The method of claim 24, wherein the current is constant current in the range of 1 mA/cm ^<2> to 10 mA/cm ^<2> . 25. The method of claim 24, wherein said anodizing said substrate is performed at a temperature of 20<0>C to 30<0>C. 33. The method of claim 32, wherein said anodizing said substrate is performed at a current of 5 mA/ ^cm2 or less for 10 seconds to 2000 seconds. 25. The method of claim 24, wherein the top porous layer, the bottom porous layer, and the non-porous region are composed entirely of silicon. 35. The method of claim 34, wherein said silicon is single crystal. 25. The method of claim 24, wherein the lower portion of the non-porous region is composed of doped silicon or a doped silicon-germanium alloy having a germanium content of less than 10 atomic percent. 25. The method of claim 24, wherein the top porous layer has an average pore opening of less than 3 nm and the bottom porous layer has an average pore opening of greater than 3 nm. 25. The method of claim 24, wherein said first thickness of said top porous layer is 50 nm or less. 25. The method of claim 24, wherein said second thickness of said bottom porous layer is from 0.1 [mu]m to 20 [mu]m. 25. The method of claim 24, wherein the non-porous region is composed of p-doped silicon that is single crystal. 25. The method of claim 24, wherein said non-porous region and said porous region are composed entirely of p-type doped silicon. 25. The method of claim 24, wherein said silicon is p-doped silicon having a p-type dopant concentration of ¹⁰¹⁹ cm ^-3 . 25. The method of claim 24, wherein said silicon is boron doped silicon. 25. The method of claim 24, further comprising patterning the porous region comprising the top and bottom porous layers. 25. The method of claim 24, wherein the porous regions are formed on the top, bottom, or sides of any three-dimensional structure.

Images