WO2010007579A1

WO2010007579A1 - Three-dimensional solid state battery

Info

Publication number: WO2010007579A1
Application number: PCT/IB2009/053040
Authority: WO
Inventors: Nynke Verhaegh; Johan Hendrik Klootwijk; Petrus Henricus Laurentius Notten
Original assignee: Nxp B.V.
Priority date: 2008-07-14
Filing date: 2009-07-14
Publication date: 2010-01-21
Also published as: EP2308120A1

Abstract

The present invention relates to a battery in which both electrodes and the electrolyte are solids which is called a solid state battery. Solid electrolytes are a class of materials also known as superionic conductors and fast ion conductors, and their study belongs to an area of science known as solid-state ionics. As a group, these materials are very good conductors of ions but are essentially insulating toward electrons, properties that are prerequisites for any electrolyte. The high ionic conductivity minimizes the internal resistance of the battery, thus permitting high power densities, while the high electronic resistance minimizes its self-discharge rate, thus enhancing its shelf life. Solid-state batteries generally fall into the low-power-density and high- energy-density category. The former limitation arises because of the difficulty of getting high currents across solid–solid interfaces.

Description

THREE-DIMENSIONAL SOLID STATE BATTERY

FIELD OF THE INVENTION

A battery in which both electrodes and the electrolyte are solids is called a solid state battery. Solid electrolytes are a class of materials also known as superionic conductors and fast ion conductors, and their study belongs to an area of science known as solid-state ionics. As a group, these materials are very good conductors of ions but are essentially insulating toward electrons, properties that are prerequisites for any electrolyte. The high ionic conductivity minimizes the internal resistance of the battery, thus permitting high power densities, while the high electronic resistance minimizes its self-discharge rate, thus enhancing its shelf life. Examples of such materials include Ag₄RbIs for Ag+ conduction, L1I/AI₂O₃ mixtures for Li+ conduction, and the clay and β-alumina group of compounds (NaAIi 1O17) for Na+ and other mono- and divalent ions. At room temperature the ionic conductivity of a single crystal of sodium β-alumina is 0.035 S/cm, comparable to the conductivity of a 0.1 M HCl solution. This conductivity, however, is reduced in a battery by a factor of 2-5, because of the use of powdered or ceramic material rather than single crystals. Of much interest are glassy and polymeric materials that can be readily made in thin- film form, thus enhancing the rate capability of the overall system.

BACKGROUND OF THE INVENTION

Solid-state batteries generally fall into the low-power-density and high- energy-density category. The former limitation arises because of the difficulty of getting high currents across solid-solid interfaces. However, these batteries do have certain advantages that outweigh this disadvantage: They are easy to miniaturize (for example, they can be constructed in thin- film form), and there is no problem with electrolyte leakage. They tend to have very long shelf lives, and usually do not have any abrupt changes in performance with temperature, such as might be associated with electrolyte freezing or boiling. Being low- power devices, they are also inherently safer. The major applications of these batteries are in electronic devices such as cardiac pacemakers, cameras, electrochromic displays, watches, and calculators. Lithium all- so lid- state batteries are based on the reversible exchange of lithium ions between two electrodes (anode and cathode), which are separated by a solid-state electrolyte, which allows for Li-ion diffusion-migration and prevents electron transport. In addition, diffusion barrier layers are required to prevent the diffusion of lithium species from the electrodes into the substrate. These barrier layers (possibly combined with a current collector) should allow for (external) electron transport from anode (negative electrode) towards cathode (positive electrode) during discharge (and vice versa during charge).

Commercially available lithium (Li) rechargeable batteries supply current at voltage values that range between 1.5-4 volts (V) and energy density of 1-120 milliwatt- hour/gram(mWh/g) with thickness on the order of about 2 millimeters (mm). The low specific energy (< lmWh/g) and voltage requirements (< 2 V) of complementary metal- oxide-semiconductor (CMOS) technology have provided new possibilities for materials and processes, but at present, power sources conventionally remain outside integrated circuit packages. Various batteries are known from the prior art.

US3647542 Bl discloses an electrode-separator unit in the form of a nonmetallic honeycomb matrix, e.g., of porous organic or inorganic material, and having first catalyst electrode material, e.g., platinum, and second active battery electrode material, e.g., zinc, separately contained in cells of the honeycomb matrix, and a fluid operable battery incorporating the above honeycomb electrode-separator unit.

US2006/154141 Al discloses a battery. In order to increase the capacity of an "all-solid" type micro -battery, the layer of electrolyte is structured: transversing cavities are created in the flat layer of electrolyte, advantageously at the level of patches of collector material, and then filled by anode or cathode material. The anode and cathode materials are alternated.

WO2004093223 A2discloses a solid-state battery comprising: a plurality of stacked thin film layers, wherein the solid-state battery is at least partially integrated within the stacked layers and has a thickness less than about 1 μm, and method for making same. The stacked thin film layers comprise typically a cathode layer, an electrolyte layer, and an anode layer.

WO2005101973 A2 discloses an electrical energy storage device, which includes a substrate, which is formed so as to define a multiplicity of micro-containers separated by electrically- insulating and ion-conducting walls. A first plurality of anodes (A) is disposed in a first subset of the micro-containers, and a second plurality of cathodes is disposed in a second subset of the micro-containers. The anodes and cathodes are arranged in an interlaced pattern.

US6432577 Bl discloses an apparatus and method for fabricating a microbattery that uses silicon as the structural component, packaging component, and semiconductor to reduce the weight, size, and cost of thin film battery technology. When combined with advanced semiconductor packaging techniques, such a silicon-based microbattery enables the fabrication of autonomous, highly functional, integrated microsystems having broad applicability. It comprises a dielectric porous membrane; a first electrode containing anodic material mounted on one side of the porous membrane; a second electrode containing cathodic material mounted on the opposite side of the porous membrane; a first silicon frame mounted with the first electrode and on the side opposite the porous membrane; a second silicon frame mounted with the second electrode and on the side opposite the porous membrane; and electrical connectors passing through each frame for providing electrical connectivity from the first and second electrodes to external circuitry. Si wafers typically form the frames, and thus the structure comprises four Si wafers. The porous membrane separates the anode and cathode.

In an article called "Mechanical characterization of honeycomb electrode support structures" Dustin Beeaff and Greg Hilmas focus on modifying the structure of electrodes using an underlying zirconia honeycomb laminated to the zirconia electrolyte. The structure increases the strength of the electrode structure and should allow for thinner electrodes, increasing gas transport to the electrolyte and reduced overpotential. In addition to improved mechanical performance, the design may alleviate problems due to NiO formation at moderated temperatures (<700°C) experienced in SOFCs that have Ni-YSZ anodes. Currently, nickel-based anodes must be protected from oxidation by flowing forming gas (N₂/H₂) during cool down.

In the Journal of Membrane Science 310 (2008) 1-6, "Preparation of micro- porous membrane electrodes and their application in preparing anodes of rechargeable lithium batteries", Haipeng Zhao et al, disclose a micro-porous membrane-based template, which was used to prepare micro-porous membrane alloy composite anode for lithium-ion batteries. The polymer poly acrylonitrile (PAN) micro-porous membrane was prepared on a Cu substrate by a phase inversion using both vapor and coagulating bath, successively, forming the micro-porous membrane electrode. Tin and copper were simultaneously electrodeposited in the pores of the microporous membrane electrode. After heat-treatment, the composite Sn-Cu alloy anode was obtained, while the PAN became conjugated conducting polymer. The micro-porous membrane presented the micro-pore size of ca. 900 nm and the porosity of 74.7%. The prepared composite anode exhibited a stable cycling performance for lithium storage. This paves a promising way to use micro-porous polymer membrane technique to prepare composite alloy anode for rechargeable lithium-ion batteries. However, all of the above batteries suffer from a limited lifetime, for various reasons. The most important is that the batteries wear out in terms electrolyte leaking out of the active system, and in terms of electrolyte become less active.

Further, most of the above batteries lack mechanical stability, which is a requirement for many applications. Also, many of the above batteries are difficult to manufacture.

Not only are the above batteries difficult to manufacture, but also the methods used for manufacture are not fully integrated in standard IC-production methods, and often do not fit at all in said methods.

Further, many of the above batteries use a first type of material for the anode battery material and a second type of material, different from the first type, for the cathode battery material, also adding up to e.g. the complexity of manufacture.

Thus there still is a need for a simple, robust, thin and durable battery having small dimensions and a good performance in terms of provided current and voltage. Further there is a need for a battery, which can be manufactured by a method which is fully integrated in standard IC manufacturing methods and which method is relatively simple.

SUMMARY OF THE INVENTION

The present invention relates to a solid state battery comprising a substrate, a diffusion barrier layer, an anode, a solid state electrolyte, and a cathode, wherein the anode or cathode is formed by an electrically conducting 3D structure, preferably a honeycomb structure, which 3-D structure forms one or more containers, wherein further the diffusion barrier layer is located on the substrate and underneath the 3D structure, wherein the solid state electrolyte is present in the one or more containers and further in between the 3-D structure and cathode or anode, respectively, as well as to a method of making the same, and to devices comprising said battery.

The present battery is easy to manufacture, and the methods used for manufacture are fully integrated in standard IC-production methods, and fit in said methods. Further, a standard IC material is used for both electrodes, also adding up to the simplicity of manufacture. Thus further allows for interchanging the electrodes, i.e. cathode and anode.

The present battery is a simple, robust, thin and durable battery having small dimensions and a good performance in terms of provided current and voltage. Further the present battery can be manufactured by a method which is relatively simple.

With respect to prior art batteries the present battery provides a significantly larger surface available for the one or more electrolytes. Also the current density per unit area with respect to prior art batteries is at present increased significantly, such as by a factor 10, or even 50, especially in a case where double sided integration is used. The present 3D structure, especially the honeycomb structure, provides similar advantages as the double sided integration.

Further, the mechanical stability, especially in terms of stability provided during operation, which includes increase and decrease of electrode volume due to e.g. intercalation, is significantly increased. For instance, the chance on crack forming, which is a significant problem with prior art batteries (see Fig. 5), is reduced dramatically or totally absent.

In view of the above advantages the life time of the present battery will be a factor larger than that of prior art batteries, such as at least a four times longer lifetime. At the same time the current density per unit area is also increased, as well as the charging capacity, so the present battery also provides synergetic effects with respect to the prior art batteries.

DETAILED DESCRIPTION OF THE INVENTION In a first aspect the present invention relates to a solid state battery comprising a substrate, a diffusion barrier layer, an anode, a solid state electrolyte, and a cathode, wherein the anode or cathode is formed by an electrically conducting 3D structure, preferably a honeycomb structure, which 3-D structure forms one or more containers, wherein further the diffusion barrier layer is located on the substrate and underneath the 3D structure, wherein the solid state electrolyte is present in the one or more containers and further in between the 3-D structure and cathode or anode, respectively.

The diffusion barrier is typically a dielectric layer, such as SiO₂, silicon nitride, titanium nitride, tantalum nitride, etc. The barrier layer should be thick enough, in order to prevent ion diffusion through the layer, e.g. diffusion of Li ions. Due to the present construction the anode and cathode electrode configurations as such are interchangeable. Preferably the anodes include lithium insertion compounds including at least one of silicon, carbon, graphite, lithium alloys and lithium. At least one of the anode and cathode may include silicon and/or lithium, at least one of a lithium-metal alloy, a III-V compound, a II-VI compound, a nitride, lithium intercalated into graphite, an oxide, at least one OfLi₂₂SnS, LiCoO₂, titanium nitride, nickel suicide, cobalt suicide, titanium oxide, and a transition metal oxide. Preferably the anode is made from Si and the cathodes include at least one OfMoS₂, FeS₂, WS₂, LiCoO₂, LiNiO₂ and Lii_+xMn₂__yθ4 material, preferably the cathode is made of lithiumcobaltoxide (LiCoO₂). The battery may be integrated within and operative Iy connected to an integrated circuit defined on the substrate. A contact layer may be disposed over the battery.

A distinction may be made between two basic types of cells: the non- rechargeable primary battery, which supplies energy during a single discharge and the rechargeable, or secondary battery, which supplies energy during a plurality of discharges. Two of the major improvements sought by the battery industry are smaller dimensions and high energy densities.

Higher energy densities may be achieved by reducing the weight of the battery or by increasing the magnitude of energy exchange in the electrochemical cell or both.

The solid state electrolyte is preferably chosen from the group comprising LiPON (Li₂^PO_3-3No_-36), The solid state electrolyte is present in the one or more containers. Typically the number of containers in a preferred embodiment is more than ten thousand; preferably even more than fifty thousand, such as more than one hundred thousand, such as more than one million. A larger number of containers improve the performance of the battery in terms of lifetime, voltage and current supplied, and mechanical stability. The total amount of electrolyte, such as Li, is, however, limited by the volume and surface of the cathode.

In terms of reliability it is important to prevent sharp corners in any structure, in particular when considering leakage currents and breakdown issues. Etch technology and lithography will results in smoothening of the corners, which provides a further advantage. However, a most optimal and preferred structure is realized by a circular structure, preferably with a polygonal symmetry, such as with six fold symmetry.

Evidently, other chemistry, leading to 3D-integrated capacitors and batteries, are also included in this invention. The chemistry mentioned above is just meant as a typical example. In a preferred embodiment the solid state battery according to the invention comprises containers in the 3D structure wherein the diameter thereof is from 0.5 to 10 μm, preferably from 1-5 μm, such as 3 μm. In a preferred embodiment a honeycomb pattern is used as 3D structure. However other 3D structures are considered as well, such as tripods, undulating structures, such as wall type patterns, and combinations thereof, such as undulating honey comb or polygonal structures. A schematic view is shown in Fig. 2. A honeycomb structure provides increased surface area through the use of the third dimension, increased mechanical stability and more open area for improved diffusion of reactants during deposition and etching. In case of 3D batteries this honeycomb structure brings an additional advantage. When the silicon is patterned as a honeycomb it can be used directly as anode (or cathode) for the battery, reducing the number of layers (e.g. difficult barrier layers) to be deposited for realization a complete battery stack. The diameter of the six-fold opening is typically 3 μm, but can of course be adapted to larger or smaller values. The thickness of the honeycomb walls, however, is at present limited by lithography and etching techniques. A silicon anode will expand when Li diffuses (or intercalates) into it. By increasing the thickness of this silicon layers, e.g. by at least a factor 1.5, such as a factor two or a factor 3, this expansions will be significantly reduced, which provides an additional increased mechanical stability. It is very important that, due to absorption of ions in the anode, as intercalating ions, the electrode shrinks and expands; enough open space in the electrode is available to allow for this shrinking and expansion. As such the invention relates to the use of a 3D structure, which allows for shrink and expansion due to intercalating ions.

The 3D structure further provides increased mechanical stability and increased open diffusion area for the reactants, e.g. electrolytes. In addition, the silicon can be used directly as anode without the need for barriers layers, which simplifies the realization of batteries in 3D silicon significantly.

In comparison to other 3-D microbatteries known in the art, the microbatteries described herein provide superior energy density. The fabrication processes described below are relatively straightforward to implement. Furthermore, the disclosed configurations enable the use of a large variety of anode and cathode materials. Similarly, the disclosed configurations enable the use a variety of electrolyte materials.

In a preferred embodiment the present solid state battery comprises a substrate, which is silicon. Thereby, the battery can be manufactured simply within existing IC-technology. In yet another embodiment, the substrate includes at least one of silicon, gallium arsenide, silicon carbide, a ceramic material, a glass, a thermoelastic polymer, and a thermoplastic polymer.

In a further preferred embodiment the present solid state battery comprises a honeycomb structure, which is formed of silicon, preferably poly silicon or mono crystalline silicon, more preferably N- or P-doped silicon. Poly silicon and mono crystalline silicon can be manufactured simply within existing IC-technology. Doping can be provided by an ion implantation step, typically requiring an extra mask step, which doping provides an increased conductivity.

In yet a further preferred embodiment the present solid state battery comprises a cathode or anode, which is present above the solid state electrolyte, respectively. This embodiment provides a simple way of manufacturing. Further, the electrode provides a relative large surface area, thereby improving the voltage and current characteristics of the present battery.

In yet a further preferred embodiment the present solid state battery comprises further a poly silicon layer, which is present on the diffusion barrier layer and underneath the 3D structure. This poly silicon layer further increases the surface area of the electrode. However, this layer may not be too thick, as otherwise too much of electrolyte, e.g. Li ions, intercalate into the silicon, thereby reducing the lifetime of the battery. A preferred thickness is from 0.02-1.0 μm, preferably from 0.05-0.5 μm, such as from 0.08-0.3 μm, e.g. 0.1 μm. In yet a further preferred embodiment the present solid state battery comprises a 3-D structure has more than 50% open space, preferably more than 70 % open space, such as more than 80% open space. Such a configuration is accomplished by carefully selecting the ratio of thickness of the walls forming the one or more containers at the one hand, and the size of the inner space of the containers at the other hand. Referring to Fig. 2, a relative smaller thickness (130) with respect to the diameter (120) will result in more open space. The more open space is provided, the more electrolytes may be present. On the other hand, the 3D structure should preferably have a large surface area, which is provided by less open area and/or specific choice of the form of the structure, e.g. spherical structures would provide more surface area. The surface should also not be too large; otherwise too much electrolyte will eventually be intercalated.

In yet a further preferred embodiment the present solid state battery comprises a substrate with a thickness which is from 50-250 μm, wherein the thickness of the barrier layer is from 0.02-1.0 μm, wherein the thickness of the 3-D structure is from 0.02-1.0 μm, wherein the thickness of the solid state electrolyte is from 0.2-2.0 μm, and wherein the thickness of the cathode or anode is from 0.2-2.0 μm.

As such the total stack is preferably in the order of 2 μm (e.g. 0.1 μm barrier layer; 0.1 μm anode; 0.5 μm solid state electrolyte, 1.0 μm cathode, 0.1 μm current collector, all being approximate values).

In yet a further preferred embodiment the present solid state battery further comprises an enclosure for containing the battery. The enclosure protects the battery from environmental influences, and maintains the integrity of the battery.

Other typical components as one or more current collectors, contacts etc. are typically also present. Current collectors or contacts are electrically conductive materials, e.g., metals that do not react with or allow diffusion of ions. Preferred metals for use with lithium sources include copper (Cu), titanium (Ti), and aluminum (Al), and combinations thereof. The metallization interconnects in microelectronics are currently moving from the use of Al and SiO₂ as the metal and inter-metal dielectric, respectively, to Cu and low-k dielectrics in order to reduce capacitance delays. From the perspective of thin- film battery fabrication using lithium sources, this is a positive trend because Al reacts with Li to form Li- Al alloys, whereas Cu is more inert to lithium. Nevertheless, metals used for suicides, such as Ti, may be used to deposit a lithium diffusion barrier as an integral part of the contact and prevent direct Li and Al interaction. More generally, metal layers that are inert with respect to the material comprising an electrode, i.e. a cathode or anode, may be formed between the electrode and a highly conductive metal to improve contact.

In a second aspect the present invention relates to a method of manufacturing a solid state battery, which comprises the steps of: providing a substrate, preferably a Si substrate, - depositing a diffusion barrier layer on the substrate, preferably a dielectric layer, such as SiO₂, depositing a poly crystalline or mono crystalline silicon layer on the dielectric layer, optionally N- or P- type doping the silicon layer, - etching a 3D structure in the silicon layer thereby forming one or more containers, filling the containers with a solid state electrolyte, providing a further layer on top of the electrolyte, and forming contacts. In planar devices the battery material stack is preferably deposited by Physical Vapor Deposition (PVD).

Using Physical Vapor Deposition (PVD) all- so lid- state batteries have been realized successfully. However, in order to increase the capacity the battery area must increase significantly. This can be realized by growing these devices in/on 3 dimensional (3D) substrates. Examples of 3D configurations are pores, trenches, pillars, etc. The capacity increase then depends on the surface enhancement, which is related to the aspect ratio and the number of 3D units.

Atomic Layer Deposition (ALD) and/or Chemical Vapor Deposition (CVD) can achieve deposition of multi- layer stacks in 3D.

With ALD it is possible to deposit layers at low-temperature in 3D configurations with high uniformity and step conformity. However ALD is slow, still under development, and thus not suitable for industrialization yet. Low Pressure Chemical Vapor Deposition (LPCVD) is generally accepted and widely used in production environments and is also known for its deposition in 3D. For less volatile and more complex materials Metal- Organic Chemical Vapor Deposition (MOCVD) can be considered.

Pores are well-known structures that have been used successfully to increase the area of devices in silicon using the third dimension. However, using the technologies mentioned above it is very hard to deposit layers, in particular battery layers, uniformly in pore-array structures, due to limited diffusion of reactive species.

To solve this problem pillar like structures, in particular tripods have been proposed as alternative 3D solution. These structures provide increased area enhancement with wider open area, improving the diffusion of reactive species. However, the mechanical stability may be a major thread to successful integrating these structures. Etching of the open area can be performed by reactive ion etching (RIE), the so called Bosch process, and by a similar cryogenic etching process, or combinations thereof.

In a third aspect the present invention relates to a device comprising a solid state battery according to the invention, such as a microelectronic device, a high speed low power device, a device comprising one or more LEDs, a laser, a mobile phone, a computer, a photo camera, and a rechargeable battery.

The present invention is meant to cover any combination of the above- mentioned preferred embodiments. The present invention is further elucidated by the following Figures and examples, which are not intended to limit the scope of the invention. The person skilled in the art will understand that various embodiments may be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a schematic diagram of a battery. Fig. 2 shows a cross section of the present battery, though not fully manufactured.

Fig. 3 shows a further cross section A-A' of Fig. 2. Figs. 4 (a, b) show a cross section of the present battery.

Fig. 4 (c) shows a schematic view of the present battery. Fig. 5 shows a SEM cross section of a prior art battery.

DETAILED DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic diagram of a battery. Therein an anode (100), an electrolyte (110), a cathode (120), and two contacts (130), one per electrode, are shown.

Fig. 2 shows a cross section of the present battery, though not fully manufactured. A 3D structure, in the form of a honeycomb is shown. Walls (100) surround containers comprising an alectrolyte (140). The walls are typically formed by etching structures in a silicon layer. Thereafter, the walls may be doped, and the thickness of the walls may be increased by e.g. LPCVD deposition of silicon.

Fig. 3 shows a further cross section A-A' of Fig. 2. Walls (200), a diffusion barrier layer (250) and a substrate (260) are visible.

Fig. 4 (a) shows a cross section of the present battery. Walls (300), a diffusion barrier layer (350) and a substrate (360) are visible. Further the electrolyte (340), present in the one or more containers and in between containers and 3D structure on the one hand and electrode (370) on the other hand, is visible. Also contacts are indicated.

Fig. 4 (b) shows an alternative and preferred cross section of the present battery. Therein, the electrolyte (340) follows, during deposition thereof and as a consequence in the final battery, the underlying structure, e.g. the honeycomb, in a "step conform" manner. The electrolyte may have an overall thickness of 0.2-2.0 μm, preferably form 0.5-1.5 μm, such as 1.0 μm. This thickness may vary somewhat over the 3D structure. Also the electrode (370) may then follow the underlying structure, i.e. that of the electrolyte. As a consequence the electrode (370) will be present within the 3D structure, to a certain depth (380) indicated with a double-headed arrow. This depth or length of the electrode (370) may extent virtually down towards the dielectric layer (350). Then, only a relatively thin electrolyte layer is present in between the electrode (370) and the barrier layer (350), e.g. having a thickness of about 1.0 μm. As such, this preferred embodiment provides an optimal use of the 3D surface, leading to an improved voltage, current and lifetime.

Fig. 4 (c) shows a schematic view of the present battery. This Figure provides a worked open perspective view of the above Fig. 4 (top).

Fig. 5 shows a SEM cross section of a prior art battery. One can clearly observe that the bulk wafer substrates used in this battery is fully disintegrated, as a consequence of the Li ions repetitively intercalating into the substrate and back into the electrolyte.

Claims

CLAIMS:

1. Solid state battery comprising a substrate (360), a diffusion barrier layer (350), an anode (300, 370), a solid state electrolyte (340), and a cathode (370, 300), wherein the anode or cathode is formed by an electrically conducting 3D structure (300), preferably a honeycomb structure, which 3-D structure forms one or more containers, wherein further the diffusion barrier layer is located on the substrate and underneath the 3D structure, wherein the solid state electrolyte is present in the one or more containers and further in between the 3-D structure and cathode or anode, respectively.

2. Solid state battery according to claim 1, wherein the diameter of the containers in the 3D structure is from 0.5 to 10 μm, preferably from 1-5 μm, such as 3 μm.

3. Solid state battery according to any of claims 1-2, wherein the substrate is silicon.

4. Solid state battery according to any of claims 1-3, wherein the honeycomb structure is formed of silicon, preferably of poly silicon or mono crystalline silicon, more preferably of N- or P-doped silicon.

5. Solid state battery according to any of claims 1-4, wherein the cathode or anode is present above the solid state electrolyte, respectively.

6. Solid state battery according to any of claims 1-5, wherein further a poly silicon layer is present on the diffusion barrier layer and underneath the 3D structure.

7. Solid state battery according to any of claims 1-6, wherein the 3-D structure has more than 50% open space, preferably more than 70 % open space, such as more than 80% open space.

8. Solid state battery according to any of claims 1-7, wherein the thickness of the substrate is from 50-250 μm, the thickness of the barrier layer is from 0.02-1.0 μm, the thickness of the 3-D structure is from 0.02-1.0 μm, the thickness of the solid state electrolyte is from 0.2-2.0 μm, the thickness of the cathode or anode is from 0.2-2.0 μm.

9. Solid state battery according to any of claims 1-8, which further comprises an enclosure for containing the battery.

10. Method of manufacturing a solid state battery according to any of claims 1-9, which comprises the steps of: providing a substrate, preferably a Si substrate, depositing a diffusion barrier layer on the substrate, preferably a dielectric layer, such as SiO₂, depositing a poly crystalline or mono crystalline silicon layer on the dielectric layer, optionally N- or P- type doping the silicon layer, etching a 3D structure in the silicon layer thereby forming one or more containers, filling the containers with a solid state electrolyte, - providing a further layer on top of the electrolyte, and forming contacts.

11. Device comprising a solid state battery according to any of claims 1-9, such as a microelectronic device, a high speed low power device, a device comprising one or more LEDs, a laser, a mobile phone, a computer, a photo camera, and a rechargeable battery.