Solid-state battery layered positive electrode material, preparation method thereof and all-solid-state battery
The layered cathode material MOCl prepared by solid-state pyrolysis is combined with conductive carbon and solid electrolyte to solve the interface problem of cathode materials in solid-state batteries, achieving high capacity and excellent rate performance, and is suitable for all-solid-state lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2026-04-14
- Publication Date
- 2026-07-14
AI Technical Summary
The interface problem between the cathode material and the solid electrolyte in existing solid-state batteries prevents high-energy-density cathode active materials from achieving their expected energy density. Furthermore, existing cathode materials suffer from low theoretical capacity and difficulty in achieving their capacity, affecting the energy density and rate performance of the battery.
A layered cathode material MOCl (M is at least one of Fe, Bi, and V) was prepared by solid-state pyrolysis. It was then simply combined with conductive carbon and a solid electrolyte to form a composite cathode for use in all-solid-state lithium-ion batteries. The material has a two-dimensional layered structure and good ion transport performance.
It achieves high capacity and excellent rate performance, and the material is simple to synthesize and low in cost. It is suitable for liquid and all-solid-state lithium-ion battery systems and has good prospects for industrial application.
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Figure CN122393280A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid-state battery technology, specifically to a layered cathode material for solid-state batteries using MOX as the active material, its preparation method, and an all-solid-state battery. Background Technology
[0002] With the continuous development of energy technology, liquid electrolytes have been continuously developed due to their high ionic conductivity, good electrode compatibility, and good electrochemical stability. However, organic liquid electrolytes are flammable, have low safety, and suffer from severe dendrite formation, making them difficult to meet the requirements of high-energy-density batteries. To solve this problem, all-solid-state batteries using solid-state electrolytes are widely considered a very promising approach.
[0003] Currently, the most challenging aspect of solid-state batteries—solid electrolytes—has seen its ionic conductivity exceed 10⁻⁶ as research progresses. -3 The energy density (S / cm) of these materials has even surpassed that of liquid electrolytes in some cases. However, the interface problem between mainstream cathode materials and solid-state electrolytes remains unresolved, preventing high-energy-density cathode active materials from achieving their full potential. In recent years, several novel solid-state battery cathode materials with good interfacial compatibility have emerged. These materials possess high ionic conductivity and can replace solid electrolytes in traditional composite cathode materials, thereby improving battery energy density. However, these cathode materials generally suffer from low theoretical capacity and difficulty in achieving their full capacity, hindering further improvements in battery energy density and impacting the capacity and rate performance of solid-state batteries. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a layered cathode material for solid-state batteries, a method for preparing the same, and an all-solid-state battery. The layered cathode material, when applied in a solid-state battery, has a high capacity and good rate performance.
[0005] This invention proposes a type of layered cathode material for solid-state batteries, its preparation method, and its application in all-solid-state lithium-ion batteries. This invention synthesizes a layered cathode material via solid-state pyrolysis, which is then simply combined with conductive carbon and a solid electrolyte to form a composite cathode for use in solid-state batteries, exhibiting excellent capacity and rate performance.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The solid-state battery layered cathode material of the present invention is an oxide of chloride of M (abbreviated as MOCl), where M is at least one of Fe, Bi, and V.
[0007] The present invention discloses a method for preparing a solid-state battery layered cathode material by heating a metal chloride and an oxygen source to obtain a layered metal chloride oxychloride, and then washing it with a solvent to obtain a pure lithium-ion battery cathode material, namely a solid-state battery layered cathode material.
[0008] Furthermore, the oxygen source used is water or metal oxide.
[0009] Furthermore, if the oxygen source in the synthesis is water, water is required to participate in the reaction. In the presence of water molecules, the reaction can occur in air (where water molecules are present). Alternatively, the raw material can be a metal chloride containing water of crystallization, MCl3·xH2O, or an aqueous solution of MCl3. The heating rate is 5-10℃ / min. The temperature is raised to 200-250℃ (preferably 210-230℃), and held for 1-3 hours. A protective atmosphere is not required during the high-temperature calcination process, but using an argon or nitrogen atmosphere is more effective. This synthesis method is particularly suitable for the synthesis of FeOCl, while Bi and V are highly hydrolyzable and cannot be synthesized using this solid-phase decomposition method.
[0010] Furthermore, if the oxygen source in the synthesis is a metal oxide, the raw material chosen to provide the oxygen source is the metal oxide corresponding to the metal chloride. Slow heating is required, with a heating rate of 1-5℃ / min. The temperature should be raised to 400-700℃, and held for 3-5 days. This synthesis method is suitable for the synthesis of FeOCl, BiOCl, and VOCl.
[0011] Furthermore, solvent cleaning comprises two steps: water washing (preferably deionized water washing) and organic solvent washing. Water washing is preferably done with deionized water. The organic solvent used for organic solvent washing is at least one of methanol, ethanol, diethyl ether, and acetone.
[0012] The all-solid-state battery of the present invention includes the layered cathode material of the solid-state battery.
[0013] The all-solid-state battery of the present invention specifically includes an all-solid-state lithium-ion battery composite positive electrode, a solid electrolyte a, and a negative electrode; The all-solid-state lithium-ion battery composite cathode comprises the solid-state battery layered cathode material, solid electrolyte b, and conductive agent.
[0014] Furthermore, the solid electrolyte a is a bilayer electrolyte consisting of Li3InCl6 and Li 5.5 PS 4.5 Cl 1.5 Or the solid electrolyte a is Li 5.5 PS 4.5 Cl 1.5 One of Li3InCl6, Li2ZrCl6, Li6PS5Cl, etc. The negative electrode is lithium foil or lithium alloy.
[0015] Furthermore, the layered cathode material of the solid-state battery accounts for 40-70% of the total mass of the composite cathode of the all-solid-state lithium-ion battery.
[0016] Furthermore, the conductive agent is at least one selected from superconducting carbon black, carbon nanotubes, carbon nanofibers, graphene, Ketjen black, acetylene black, and activated carbon. The mass of the conductive agent accounts for 5-10% of the total mass of the composite cathode of the all-solid-state lithium-ion battery.
[0017] Furthermore, the solid electrolyte b is the same as the solid electrolyte a.
[0018] The solid-state battery layered cathode material of this invention possesses a typical two-dimensional layered structure with interlayer spacing suitable for the reversible insertion and extraction of lithium ions. When used as an intercalation-type cathode material, this material exhibits excellent ion transport performance and structural stability. When applied in all-solid-state lithium-ion batteries, this solid-state battery layered cathode material demonstrates stable charge-discharge capability and, when combined with a conductive agent, achieves stable operation in all-solid-state lithium-ion batteries at room temperature. The layered cathode material provided by this invention features a simple synthesis method, low raw material cost, and environmental friendliness, and is suitable for both liquid and all-solid-state lithium-ion battery systems, showing promising prospects for industrial applications.
[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The cathode material prepared by solid-state pyrolysis in this invention is simple to prepare, has good humidity stability, and has low requirements for the protective atmosphere during the synthesis process.
[0020] 2. The raw materials used in this invention can be elements with high abundance in the Earth's crust (iron), which has a significant cost advantage compared to the cathode materials currently reported that use high-priced transition metal elements.
[0021] 3. The layered cathode material prepared by this invention has a high theoretical capacity, exhibits high capacity utilization in all-solid-state batteries, and demonstrates excellent rate performance. Attached Figure Description
[0022] Figure 1 The results are the XRD test results from Examples 1, 2, 3, and 4. Figure 2 The figures show the SEM test results for Examples 1, 2, 3, and 4; the columns from left to right in the figures represent the SEM test results for Examples 1, 2, 3, and 4, respectively. Figure 3 The results of the rate performance tests for Examples 2 and 4 are shown. Figure 4 The results are the rate performance test results for Examples 1, 2, 3, and 4. Figure 5The specific capacitance voltage curve for Example 4; Figure 6 The specific capacitance voltage curve for Example 5; Figure 7 This is the specific capacity voltage curve for Example 6. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0024] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.
[0025] Example 1
[0026] Preparation of FeOCl material: Weigh 2g of anhydrous FeCl3 and spread it evenly in a clean porcelain boat. Place the porcelain boat in a muffle furnace, set the heating rate to 10℃ / min, heat to 200℃ and hold for 2h, then let it cool naturally to room temperature to obtain a dark purple solid. Grind it finely with a mortar and pestle, wash it once with deionized water and three times with acetone. Then, vacuum dry the washed powder at 80℃ overnight to obtain FeOCl powder, denoted as FeOCl-1.
[0027] Electrode material preparation: Weigh 0.4g FeOCl-1 and 0.1g superconducting carbon black into a ball mill jar, add 30g of grinding beads, and ball mill. Place the ball mill jar on a high-speed ball mill at 500rpm for 84h. Scrape the reacted sample out of the ball mill jar to obtain the carbon-coated electrode material FeOCl-1@C.
[0028] Preparation of solid electrolyte Li3InCl6: 1g of LiCl and InCl3 powder (molar ratio 3:1) was weighed and placed in a ball mill jar. 40g of grinding beads were added, the jar was sealed, and the mixture was placed in a high-speed ball mill at 700 rpm for 24 hours. The product was scraped from the mill jar, placed in a mold, and pressed into 10mm diameter discs under 500MPa pressure. The discs were placed in a quartz bottle and heated to 300℃ under argon atmosphere for 5 hours. The sintered discs were then removed and ground into powder in a mortar to obtain the halide solid electrolyte Li3InCl6.
[0029] Preparation of composite cathode material: Equal masses of electrolyte material FeOCl-1@C and halide solid electrolyte Li3InCl6 were ground together to mix them evenly to obtain composite cathode material.
[0030] All-solid-state lithium-ion battery assembly: A solid-state battery test mold with an inner diameter of 10 mm, manufactured by Dongguan Guli New Energy Technology Co., Ltd., was used. 60 mg of Li3InCl6 and 40 mg of Li were added respectively. 5.5 PS 4.5 Cl 1.5 (Huatuo New Energy Technology Co., Ltd.) A composite electrolyte layer was obtained by applying pressures of 1t and 2t for 1 minute on a press. 5mg of composite positive electrode material was weighed and evenly spread on one side of the halide solid electrolyte, then placed on a press and subjected to a pressure of 3t for 1 minute. A 10mm diameter indium sheet and a 6mm diameter lithium sheet (forming a lithium alloy) were added to the sulfide side, and constant current charge-discharge and rate tests were performed. During the tests, a discharge-then-charge method was adopted to prioritize lithium intercalation into the positive electrode. After the assembled battery was allowed to stand for 12 hours, electrochemical performance tests (1C=250mAh / g) were conducted. The constant current charge-discharge test was performed at 0.5C for 200 cycles. The rate test was performed at 0.1C, 0.2C, 0.5C, 1.0C, 2.0C, 5.0C, and 0.5C for 5 cycles each, then returned to 0.1C for 20 cycles to detect the cycle performance at different rates.
[0031] Example 2
[0032] Preparation of FeOCl material: Weigh 2g of FeCl3·6H2O and spread it evenly in a clean porcelain boat. Place the porcelain boat in a muffle furnace, set the heating rate to 10℃ / min, heat to 200℃ and hold for 2h, then let it cool naturally to room temperature to obtain a dark purple solid. Grind it finely with a mortar and pestle, then wash it once with deionized water and three times with anhydrous ethanol. Then, vacuum dry the washed powder at 80℃ overnight to obtain FeOCl powder, denoted as FeOCl-2.
[0033] The electrode material was prepared in the same manner as in Example 1.
[0034] The solid electrolyte was prepared in the same manner as in Example 1.
[0035] The preparation method of the composite cathode material is the same as in Example 1.
[0036] The assembly method for all-solid-state lithium-ion batteries is the same as in Example 1.
[0037] Example 3
[0038] Preparation of FeOCl material: Weigh 2g of FeCl3·6H2O and spread it evenly in a clean porcelain boat. Place the porcelain boat in a tube furnace and, under argon protection, set the heating rate to 10℃ / min. Heat to 200℃ and hold for 2h. Allow to cool naturally to room temperature to obtain a dark purple solid. Grind the solid finely in a mortar and pestle, wash once with deionized water and three times with acetone. Then, vacuum dry the washed powder at 80℃ overnight to obtain FeOCl powder, denoted as FeOCl-3.
[0039] The electrode material was prepared in the same manner as in Example 1.
[0040] The solid electrolyte was prepared in the same manner as in Example 1.
[0041] The preparation method of the composite cathode material is the same as in Example 1.
[0042] The assembly method for all-solid-state lithium-ion batteries is the same as in Example 1.
[0043] Example 4
[0044] Preparation of FeOCl material: Weigh 2g of FeCl3·6H2O and spread it evenly in a clean porcelain boat. Place the porcelain boat in a tube furnace and, under argon protection, set the heating rate to 10℃ / min. Heat to 200℃ and hold for 1h. Allow to cool naturally to room temperature to obtain a dark purple solid. Grind the solid finely in a mortar and pestle, wash once with deionized water and three times with acetone. Then, vacuum dry the washed powder at 80℃ overnight to obtain FeOCl powder, denoted as FeOCl-4.
[0045] The electrode material was prepared in the same manner as in Example 1.
[0046] The solid electrolyte was prepared in the same manner as in Example 1.
[0047] The preparation method of the composite cathode material is the same as in Example 1.
[0048] The assembly method for all-solid-state lithium-ion batteries is the same as in Example 1.
[0049] Example 5
[0050] Preparation of BiOCl material: Weigh 2g BiCl3 and 1g Bi2O3 into a glass tube, seal and spread them evenly. Place the glass tube in a muffle furnace, set the heating rate to 1℃ / min, heat to 500℃ and maintain for 4 days, then cool naturally to room temperature to obtain a dark purple solid. Grind it finely with a mortar and pestle, wash it once with deionized water and three times with acetone. Then, vacuum dry the washed powder at 80℃ overnight to obtain BiOCl powder, denoted as BiOCl-1.
[0051] Example 6
[0052] Preparation of VOCl material: Weigh 2g VCl3 and 1g V2O3 into a glass tube, seal and spread them evenly. Place the glass tube in a muffle furnace, set the heating rate to 1℃ / min, heat to 500℃ and maintain for 4 days, then cool naturally to room temperature to obtain a dark purple solid. Grind it finely with a mortar and pestle, wash it once with deionized water and three times with acetone. Then, vacuum dry the washed powder at 80℃ overnight to obtain VOCl powder, denoted as VOCl-1.
[0053] The electrode material was prepared in the same manner as in Example 1.
[0054] The solid electrolyte was prepared in the same manner as in Example 1.
[0055] The preparation method of the composite cathode material is the same as in Example 1.
[0056] The assembly method for all-solid-state lithium-ion batteries is the same as in Example 1.
[0057] Analysis of test results: Figure 1 The results are the XRD test results from Examples 1, 2, 3, and 4. Figure 2 The figures show the SEM test results for Examples 1, 2, 3, and 4, with the left and right columns representing the SEM test results for Examples 1, 2, 3, and 4, respectively. Figure 3 The results of the rate performance tests for Examples 2 and 4 are shown. Figure 4 The results are the rate performance test results for Examples 1, 2, 3, and 4. Figure 5 The specific capacitance voltage curve for Example 4; Figure 6 The specific capacitance voltage curve for Example 5; Figure 7 This is the specific capacity voltage curve for Example 6.
[0058] Figure 1 The XRD test results showed that the substances synthesized by different methods were all FeOCl phases, indicating that the synthesis of FeOCl is simple and suitable for large-scale applications.
[0059] Examples 1-4 were characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 2As shown in the figure. SEM results show that the particle size of the product in Example 1 is 20-50 μm, while the maximum particle size of the product in Example 2 exceeds 200 μm, and the surface is relatively rounded. The microscopic results of the products in Examples 3-4 show that they are flat, and the particles are generally larger. Morphology at high magnification shows that the materials in different examples all exhibit a certain degree of lamellarity, indicating an intercalation structure, i.e., a layered structure. The difference between Examples 1 and 2 and Examples 3 and 4 lies in the presence or absence of a protective atmosphere, resulting in different morphologies. Examples 3 and 4 have better performance, but Examples 1 and 2 can also be successfully used as solid-state cathodes. This proves that the present invention can synthesize FeOCl cathodes without argon protection, which has been confirmed by XRD. This is because different synthesis conditions lead to different morphologies, ultimately causing differences in performance.
[0060] Rate and cycle tests were conducted on Examples 1-4, respectively. Example 4 exhibited the best rate performance and the highest cycle capacity, reaching 350 mAh / g at 0.1C in the first cycle, and was successfully cycled within a voltage range of 1.6-4.0V at 0.5C. The specific capacity of the cathode material was 200 mAh / g, and after 200 cycles, the capacity retention was 60%, demonstrating excellent cycle performance.
[0061] In addition, cyclic testing was also performed on BiOCl and VOCl of the same type for verification. Figure 6 , 7 The first-cycle discharge capacity of BiOCl is 270 mAh / g, and that of VOCl is 120 mAh / g, which verifies the universality of intercalated cathode materials.
Claims
1. A layered cathode material for solid-state batteries, characterized in that, The chlorine oxide is M, where M is at least one of Fe, Bi, and V.
2. A method for preparing the solid-state battery layered cathode material as described in claim 1, characterized in that, By heating metal chloride with an oxygen source, layered metal chloride oxychloride salts are obtained, which are the layered cathode materials for solid-state batteries.
3. The method for preparing the layered cathode material for solid-state batteries according to claim 2, characterized in that, The oxygen source used is water or metal oxide.
4. The method for preparing the solid-state battery layered cathode material according to claim 3, characterized in that, If water is used as the oxygen source, a metal chloride containing water of crystallization, a saturated aqueous solution of a metal chloride, or moisture from the air can be used directly. If a metal oxide is used as the oxygen source, the metal oxide corresponding to the raw material metal chloride needs to be selected.
5. The method for preparing the solid-state battery layered cathode material according to claim 3 or 4, characterized in that, If water is used as the oxygen source, rapid heating is required, with a heating rate of 5-10℃ / min, to 200-250℃; and / or, the holding time is 1-3 hours.
6. The method for preparing the solid-state battery layered cathode material according to claim 3 or 4, characterized in that, If metal oxides are used as the oxygen source, the temperature needs to be raised slowly at a rate of 1-5℃ / min to 400-700℃; and / or, the holding time should be 3-5 days.
7. An all-solid-state battery comprising the layered cathode material of claim 1.