GB2619643A

GB2619643A - Preparation method for nickel phosphide@carbon negative electrode material having porous structure, and use thereof

Info

Publication number: GB2619643A
Application number: GB2314014.8A
Authority: GB
Inventors: Xie Yinghao; Yu Haijun; Li Aixia; Zhang Xuemei; Li Changdong
Original assignee: Hunan Brunp Recycling Technology Co Ltd; Guangdong Brunp Recycling Technology Co Ltd; Hunan Bangpu Automobile Circulation Co Ltd
Current assignee: Hunan Brunp Recycling Technology Co Ltd; Guangdong Brunp Recycling Technology Co Ltd; Hunan Bangpu Automobile Circulation Co Ltd
Priority date: 2022-02-17
Filing date: 2022-12-01
Publication date: 2023-12-13
Anticipated expiration: 2042-12-01
Also published as: DE112022002496T5; CN114639805B; HUP2400173A1; GB2619643B; CN114639805A; WO2023155542A1; GB202314014D0

Abstract

The present invention discloses a preparation method for a nickel phosphide@carbon negative electrode material having a porous structure, and the use thereof. The preparation method comprises: mixing a nickel salt solution with a precipitant for a reaction, and introducing carbon dioxide for a reaction to obtain a precipitate; placing the precipitate at a lower tuyere of a tubular furnace, taking anhydrous sodium hypophosphite and placing same at an upper tuyere of the tubular furnace, heating the tubular furnace, and taking out the precipitate and soaking same in a sodium hydroxide solution to obtain porous nickel phosphide; and mixing the porous nickel phosphide with organic matter for a carbonization reaction to obtain a nickel phosphide@carbon negative electrode material having a porous structure. The negative electrode material prepared in the present application has a porous structure; during charging and discharging, the porous structure therein can both buffer the volume change during the charging and discharging process and increase the contact area between an electrode and an electrolyte; and the negative electrode material has a high capacity, and good cycling performance and rate performance.

Description

PREPARATION METHOD FOR NICKEL PHOSPHIDE*CARBON NEGATIVE ELECTRODE MATERIAL HAVING POROUS STRUCTURE, AND USE THEREOF

TECHNICAL FIELD

[0001] The embodiments of the present application relate to the technical field of negative electrode materials of lithium/sodium-ion battery, and for example to a method of preparing a porous-structured nickel phosphide@carbon negative electrode material and an application thereof.

BACKGROUND

[0002] Lithium/sodium-ion battery has been used as a new type of alternative energy due to its comprehensive performance advantages such as high energy density, high voltage, and long life. The negative electrode material currently used on the market is mainly graphitic carbon, but due to the defects of its own properties, the graphitic carbon has been unable to meet the growing demand for high-efficiency lithium/sodium-ion battery It is urgent to find an negative electrode material with higher capacity and better stability to further improve the performance of lithium/sodium-ion battery Transition metal phosphide and sulfide have much higher theoretical capacities than graphitic carbons, suitable voltage platforms and environmental friendliness, and are very ideal negative electrode material of lithium/sodium-ion battery [0003] The transition metal phosphide has attracted the interest of researchers due to its important applications in magnetic refrigeration, petroleum catalytic desulfurization and hydrogenation and other industrial fields. Furthermore, due to its stable cycle reversibility, high theoretical specific capacity of charge and discharge, and better safety performance, the transition metal phosphide is an ideal choice for a novel negative electrode material of lithium/sodium-ion battery. For example, Ni3P, NiP2, and NiP3, which are rich in phosphorus sources, have all been used as negative electrode materials of lithium-ion battery Some scholars have used the hydrothermal-microemulsion method to obtain hexagonal Ni2P and tetragonal Ni12P5, but the particles prepared by this method have poor dispersion, large size, poor conductivity, uncontrollable morphology and structure, etc, and the battery will experience severe volume expansion during charge-discharge cycles, which seriously affects its electrochemical and cycling performance.

[0004] As the negative electrode material of the novel high-performance ion battery, transition metal phosphide has attracted extensive attention due to its high theoretical capacity and abundant sources. However, when metal phosphide is used as the negative electrode material of the ion secondary battery, it will produce obvious volume expansion and contraction effect with the insertion and extraction of ions, resulting in rapid capacity decay and poor rate performance.

SUMMARY

[0005] A summary of the subject matter in the detailed description herein is as follows. This summary is not intended to limit the scope of the claims.

[0006] The embodiments of the present application aim to solve at least one of the above technical problems in the existing technology. To this end, the embodiments of the present application provides a method of preparing a porous-structured nickel phosphide@carbon negative electrode material and an application thereof [0007] According to one aspect of the present application, a method of preparing a porous nickel phosphide@carbon negative electrode material is provided, including the following steps: S1 mixing a nickel salt solution with a precipitating agent for reaction, introducing carbon dioxide gas to control reaction pH to be 10.8 to 11.5, carrying out aging after the reaction is finished, and separating solid and liquid to obtain a precipitate; where the precipitating agent is a mixed solution of sodium hydroxide, sodium tetrahydroxyaluminate and sodium persulfate; S2: placing the precipitate at a lower tuyere of a tube furnace, placing anhydrous sodium hypophosphite at an upper tuyere of the tube furnace, heating the tube furnace for a period of time, taking out the precipitate and immersing the precipitate in a sodium hydroxide solution, and separating solid and liquid to obtain porous nickel phosphide;

_

S3: mixing the porous nickel phosphide with an organic substance, and performing a carbonization reaction under a condition of isolating oxygen to obtain a porous-structured nickel phosphide@carbon negative electrode material.

[0008] In some embodiments of the present application, in step Si, a concentration of the nickel salt solution is Imola,/ to 2moUL; in the precipitating agent, a concentration of the sodium tetrahydroxyaluminate is 0.05mol/L to 0.2moUL, a concentration of the sodium hydroxide is 3mol/L to 6moUL, a concentration of the sodium persulfate is lmol/L to 2mol/L, and a mixing mode is adding in parallel, and a flow rate of the nickel salt solution and a flow rate of the precipitant agent are controlled so that a molar ratio of nickel and aluminum is 10: (1 to 2).

[0009] In some embodiments of the present application, in step Si, the nickel salt solution is at least one of nickel sulfate solution, nickel chloride solution or nickel nitrate solution.

[0010] In some embodiments of the present application, wherein in step Si, after obtaining the precipitate through solid-liquid separation, the method further includes washing and drying the precipitate.

[0011] In some embodiments of the present application, in step Si, the aging time is lh to 2h.

[0012] In some embodiments of the present application, in step S2, a mass ratio of the anhydrous sodium hypophosphite to the precipitate is (8 to 15): 1.

[0013] In some embodiments of the present application, in step S2, a heating temperature of the tubular furnace is 300°C to 400°C; and a heating time of the tubular furnace is 120min to 180min. A heating rate of the tubular furnace is 2°C/mmn to 5°C/min.

100141 In some embodiments of the present application, in step S2, after being taken out, the precipitate is first cooled to below 10°C, and a temperature of the sodium hydroxide solution is 2°C to 8°C.

[0015] In some embodiments of the present application, in step S2, a concentration of the sodium hydroxide solution is 0.1moUL to 2moUL; and an immersing time is 10min to 25min.

[0016] In some embodiments of the present application, in step S3, the organic substance is at least one of sucrose, glucose or lactose.

100171 In some embodiments of the present application, in step S3, a carbonization temperature is 500°C to 800°C; and a carbonization time is I h to I 2h.

[0018] The present disclosure further provides use of the above preparation method in a sodium-ion battery or a lithium-ion battery 100191 According to a preferred embodiment of the present application, it has at least the following beneficial effects.

100201 1. In the present application, aluminum-doped nickel oxide hydroxide is prepared firstly, and then the aluminum-doped nickel oxide hydroxide reacts with sodium hypophosphite to obtain nickel aluminum phosphide. The nickel aluminum phosphide is immersed in cold sodium hydroxide to obtain a porous-structured nickel phosphide negative electrode material. After further carbonization, the target product porous-structured nickel phosphide@carbon negative electrode material is obtained.

[0021] 2. During the preparation of aluminum-doped nickel oxide hydroxide, sodium hydroxide and sodium persulfate are mixed with sodium tetrahydroxyaluminate. On the one hand, nickel oxide hydroxide is directly prepared; and on the other hand, aluminum is coprecipitated in the form of aluminum hydroxide, to achieve atomic-level mixing of nickel and aluminum; and the reaction equation is as follows: 2N12++S2082-+60H-=2N100H+2S042-+2H20; 2[A1(01-1)4]-+CO2= 2A1(OH)3+C032-+H20.

[0022] 3. The sodium hypophosphite is heated to generate phosphine, the phosphine reacts with the aluminum-doped nickel oxide hydroxide to obtain nickel aluminum phosphide. Taking an advantage of the easy solubility of aluminum phosphide, the nickel aluminum phosphide was immersed in cold sodium hydroxide solution to remove aluminum, so that atomic vacancies are vacated around the nickel atoms, which is beneficial to the volume expansion of the negative electrode material during the charge-discharge reaction; the reaction equation is as follows: 5N0-42P02-2PFL+21-12+Na4P207+NaP03; 4NiO0H+3H2+2PH3=2Ni2P+8H20; Al(OH)3+PH3=A1P+31-T20; A1P+Na0H+3H20=Na [Al(OH).4] +PH3 [0023] 4. The negative electrode material prepared by the present application is nano-scale, with a particle size of 1 Onin to 100 nin, and has a porous structure. During the charging and discharging process, its internal porous structure can not only buffer the volume change caused by the charging and discharging process, but also can increase the contact area between the electrode and the electrolyte, and has high capacity, excellent cycle and rate performance. in addition, through the carbonization treatment, a supporting carbon skeleton structure is formed inside and outside the particles, thereby further improving the strength and conductivity of the particles.

[0024] Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the technical solutions herein, and constitute a part of the specification. The drawings are used together with the embodiments of the application to explain the technical solutions herein, and do not constitute limitations to the technical solutions herein.

[0026] The present application will be further described below in conjunction with the drawings and examples.

[0027] Figure 1 is an SEM image of a porous-structured nickel phosphide@carbon negative electrode material prepared according to example 1 of the present application.

DETAILED DESCRIPTION

[0028] The concept and technical effects of the present application will be clearly and completely described in conjunction with the examples for fully understanding of the purpose, -5 -features, and effects of the present application. Obviously, the described examples are only a part of the examples of the present application, rather than all the examples. Based on the examples of the present application, other examples obtained by those skilled in the art without creative work shall fall within the protection scope of the present application.

Example I

[0029] A porous-structured nickel phosphide@carbon negative electrode material was prepared in this example. The specific processes were as follows.

[0030] (1) A nickel sulfate solution of lmol/L was prepared.

[0031] (2) A precipitating agent was prepared The precipitating agent was a mixed solution of sodium hydroxide, sodium tetrahydroxyaluminate, and sodium persulfate, where the concentration of sodium tetrahydroxyaluminate was 0.05moUL, and the concentration of sodium hydroxide was 3mol/L, the concentration of sodium persulfate was 1mol/L.

100321 (3) The nickel sulfate solution and the precipitating agent were added into a reactor in parallel, carbon dioxide gas was introduced to control the reaction pH to be 11.5, and a flow rate of the nickel salt solution and a flow rate of the precipitant agent were controlled so that a molar ratio of nickel and aluminum was 10:2.

100331 (4) After the reaction was finished, the aging was carried out for lh, and solid and liquid were separated to obtain a precipitate.

[0034] (5) The precipitate was washed and dried, and then placed at a lower tuyere of a tube furnace [0035] (6) Anhydrous sodium hypophosphite was placed at an upper tuyere of the tube furnace, and a mass ratio of the anhydrous sodium hypophosphite to the precipitate was 8:1.

[0036] (7) The tube furnace was heated to 300°C at a heating rate of 2°C/min for 180min.

[0037] (8) After the reaction of step (7) was finished, the precipitate was taken out and cooled to below 10°C, and immersed in a sodium hydroxide solution with a temperature of 2°C to 8°C and a concentration of 0.Imol/L for 25min [0038] (9) After the solid-liquid separation, the precipitate was washed with deionized water and dried to obtain porous nickel phosphide.

[0039] (10) The porous nickel phosphide was mixed with a sucrose solution. Under the condition of isolating oxygen, they were reacted at 500°C for 2h to obtain a porous-structured nickel phosphide@carbon negative electrode material with a particle size of lOnm tol 00nm

Example 2

100401 A porous-structured nickel phosphide@carbon negative electrode material was prepared in this example. The specific processes were as follows.

[0041] (1) A nickel chloride solution of I.5mol/L was prepared.

[0042] (2) A precipitating agent was prepared The precipitating agent was a mixed solution of sodium hydroxide, sodium tetrahydroxyaluminate, and sodium persulfate, where the concentration of sodium tetrahydroxyaluminate was 0.1mol/L, and the concentration of sodium hydroxide was 5mol/L, the concentration of sodium persulfate was 1.5mol/L.

100431 (3) The nickel chloride solution and the precipitating agent were added into a reactor in parallel, carbon dioxide gas was introduced to control the reaction pH to be 11.1, and a flow rate of the nickel salt solution and a flow rate of the precipitant agent were controlled so that a molar ratio of nickel and aluminum was 10:1.

[0044] (4) After the reaction was finished, the aging was carried out for I h, and solid and liquid were separated to obtain a precipitate.

[0045] (5) The precipitate was washed and dried, and then placed at a lower tuyere of a tube furnace [0046] (6) Anhydrous sodium hypophosphite was placed at an upper tuyere of the tube furnace, and a mass ratio of the anhydrous sodium hypophosphite to the precipitate was 11:1.

[0047] (7) The tube furnace was heated to 350°C at a heating rate of 3°C/min for 150min.

[0048] (8) After the reaction of step (7) was finished, the precipitate was taken out and cooled to below 10°C, and immersed in a sodium hydroxide solution with a temperature of 2°C to 8°C and a concentration of lmol/L for 15min.

[0049] (9) After the solid-liquid separation, the precipitate was washed with deionized water and dried to obtain porous nickel phosphide.

[0050] (10) The porous nickel phosphide was mixed with a glucose solution. Under the condition of isolating oxygen, they were reacted at 600°C for 6h to obtain a porous-structured nickel phosphide@carbon negative electrode material with a particle size of lOtam tolOOnm

Example 3

[0051] A porous-structured nickel phosphide@carbon negative electrode material was prepared in this example. The specific processes were as follows.

[0052] (1) A nickel nitrate solution of 2mol/L was prepared.

100531 (2) A precipitating agent was prepared. The precipitating agent was a mixed solution of sodium hydroxide, sodium tetrahydroxyaluminate, and sodium persulfate, where the concentration of sodium tetrahydroxyaluminate was 0.2mol/L, and the concentration of sodium hydroxide was 6mol/L, the concentration of sodium persulfate was 2mol/L.

100541 (3) The nickel nitrate solution and the precipitating agent were added into a reactor in parallel, carbon dioxide gas was introduced to control the reaction pH to be 10.8, and a flow rate of the nickel salt solution and a flow rate of the precipitant agent were controlled so that a molar ratio of nickel and aluminum was 10:1.

[0055] (4) After the reaction was finished, an aging was carried out for 2h, and solid and liquid were separated to obtain a precipitate.

[0056] (5) The precipitate was washed and dried, and then placed at a lower tuyere of a tube furnace [0057] (6) Anhydrous sodium hypophosphite was placed at an upper tuyere of the tube furnace, and a mass ratio of the anhydrous sodium hypophosphite to the precipitate was 13: 1.

[0058] (7) The tube furnace was heated to 400°C at a heating rate of 5°C/min for 120min.

100591 (8) After the reaction of step (7) was finished, the precipitate was taken out and cooled to below 10°C, and immersed in a sodium hydroxide solution with a temperature of 2°C to 8°C and a concentration of 2mol/L for 10min.

[0060] (9) After the solid-liquid separation, the precipitate was washed with deionized water and dried to obtain porous nickel phosphide.

[0061] (10) The porous nickel phosphide was mixed with a solution. Under the condition of isolating oxygen, they were reacted at 800°C for 12h to obtain a porous-structured nickel phosphide@carbon negative electrode material with a particle size of I Onm to I 00nm.

Comparative example

[0062] In this comparative example, nickel phosphide was prepared by hydrothermal method, and the specific processes were as follows.

[0063] Nickel nitrate and sodium hypophosphite were mixed to obtain a suspension solution.

The suspension solution was aged in a water bath at 60°C for 2h and sonicated for 30min. The liquid was poured into a hydrothermal reactor, reacted at 120°C for 12h, taken out, and left to stand for stratification to obtain a black solid. The black solid was washed with deionized water and ethanol solution, and filtered, and the filter cake was dried at 60°C to obtain a black powder nickel phosphide (Ni2P).

Test example

[0064] The negative electrode materials obtained in examples 1 to 3 and nickel phosphide obtained in the comparative example were taken to respectively prepare the negative electrode pole pieces of lithium-ion battery, the metal lithium plate was take as the positive electrode, and the above negative electrode and positive electrode were assembled into a CR2025 button battery The test was carried out at the charge and discharge voltage of 0.01V to 3V, a current density of 100mA/g (0.1C). The results were shown in Table 1.

Table I

Gram capacity after Gram capacity after Gram capacity after first charge and secondary charge and 100 charge and discharge discharge discharge mAh/g mAh/g mAh/g Example 1 988 899 701 Example 2 971 835 683 Example 3 979 856 682 Comparative 849 726 567

Example

[0065] It can be seen from Table 1 that the electrochemical performances of the examples were significantly better than that of the comparative example, this is because the negative electrode materials of the examples have a porous structure. During the charging and discharging process, the internal porous structure can not only buffer the volume change caused by the charging and discharging process, but also increase the contact area between the electrode and the electrolyte, thereby having high capacity, excellent cycle and rate performance. In addition, the negative electrode materials of the embodiments were also subjected to carbonization treatment, so that a supporting carbon skeleton structure was formed inside and outside the particles, which can further improve the strength and conductivity of the particles.

[0066] The examples of the present application have been described in detail above in conjunction with the accompanying drawings; however, the present application is not limited to the above examples, and various changes can be made within the scope of knowledge possessed by those of ordinary skill in the art without departing from the spirit of the present application. Furthermore, the examples of the present application and features in the examples may be combined with each other without conflict.

Claims

CLAIMS1. A method of preparing a porous-structured nickel phosph de@carbon negative electrode material, comprising the following steps: Si: mixing a nickel salt solution with a precipitating agent for reaction, introducing carbon dioxide gas to control reaction pH to be 10.8 to 11.5, carrying out aging after the reaction is finished, and separating solid and liquid to obtain a precipitate; wherein the precipitating agent is a mixed solution of sodium hydroxide, sodium tetrahydroxyaluminate and sodium persulfate; S2: placing the precipitate at a lower tuyere of a tube furnace, placing anhydrous sodium hypophosphite at an upper tuyere of the tube furnace, heating the tube furnace for a period of time, taking out the precipitate and immersing the precipitate in a sodium hydroxide solution, and separating solid and liquid to obtain porous nickel phosphide; S3: mixing the porous nickel phosphide with an organic substance, and performing a carbonization reaction under a condition of isolating oxygen to obtain the porous nickel phosphide@carbon negative electrode material.
2. The method according to claim 1, wherein, in step Si, a concentration of the nickel salt solution is 1 mol/L to 2mol/L; in the precipitating agent, a concentration of the sodium tetrahydroxyaluminate is 0.05mol/L to 0.2mol/L, a concentration of the sodium hydroxide is 3mol/L to 6mol/L, a concentration of the sodium persulfate is I molt to 2mol/L; and a mixing mode is adding in parallel, and a flow rate of the nickel salt solution and a flow rate of the precipitant agent are controlled so that a molar ratio of nickel and aluminum is 10: (1 to 2).
3. The method according to claim I, wherein, in step S I, the nickel salt solution is at least one of nickel sulfate solution, nickel chloride solution or nickel nitrate solution.
4. The method according to claim 1, wherein, in step S 1, after obtaining the precipitate through solid-liquid separation, the method further comprises washing and drying the precipitate.
5. The method according to claim 1, wherein, in step S2, a mass ratio of the anhydrous sodium hypophosphite to the precipitate is (8 to 15): I.
6. The method according to claim 1, wherein, in step S2, a heating temperature of the tubular furnace is 300°C to 400°C; and a heating time of the tubular furnace is 120min to 180min.
7. The method according to claim I, wherein, in step S2, after being taken out, the precipitate is first cooled to below 10°C, and a temperature of the sodium hydroxide solution is 2°C to 8°C.
8. The method according to claim 1, wherein, in step 52, a concentration of the sodium hydroxide solution is 0.1mol/L to 2mol/L; and an immersing time is 10min to 25min.
9. The method according to claim I, wherein, in step S3, the organic substance is at least one of sucrose, glucose or lactose.
10. Use of the preparation method according to any one of claims 1 to 9 in sodium-ion battery or a lithium-ion battery.-12 -