A method for recycling and regenerating lithium cobalt oxide cathodes from spent lithium batteries

Abstract

This invention discloses a method for recycling and regenerating lithium cobalt oxide cathodes from spent lithium batteries. First, pure spent lithium cobalt oxide cathodes are obtained through pretreatment. Then, a solid-state remediation method is used to simultaneously replenish lithium and regenerate spinel-like LiNi. 0.5 Mn 1.5 Micro-coating with O4 material yields directly modified and regenerated LNMO-SLCO samples. The modified and regenerated LNMO-SLCO samples of this invention exhibit high discharge capacity and good electrochemical cycling stability. The lithium-added coating modification and regeneration process not only restores the layered structure but also forms an ultrathin spinel-like material on the lithium cobalt oxide surface. Its coating layer possesses excellent Li... + The improved conductivity enhances charge transport at the surface, forming a physical barrier layer between the positive electrode and the electrolyte, thus suppressing interfacial side reactions. This invention not only provides a new and effective approach to lithium battery recycling but also offers a novel solution to the problem of poor high-voltage resistance in lithium cobalt oxide materials.

Description

Technical Field

[0001] This invention relates to the field of recycling and reuse of cathode materials from waste lithium-ion batteries, and particularly to a high-performance regeneration technology for lithium cobalt oxide cathode materials. Background Technology

[0002] The global battery market is booming, and LiCoO2 (LCO) is widely used in 3C electronic devices such as mobile phones and computers due to its high energy density, high operating voltage, and excellent electrochemical performance, accounting for a huge share of the overall LIB market. This widespread use has led to a large number of retired batteries, inevitably generating significant amounts of harmful metal elements and waste flammable electrolytes. LCO cathode materials contain metallic Li and Co, with Co being a rare and expensive element that is difficult to mine. Researching appropriate recycling technologies can not only solve the increasingly serious environmental pollution problem but also alleviate the current resource shortage, making it a key factor in promoting the sustainable development of the battery industry.

[0003] Existing recycling processes for waste LiCoO2 (SLCO) mainly fall into hydrometallurgy, pyrometallurgy, or a combination of both. These are commonly used industrial methods, offering advantages such as large scale and high efficiency. However, they are cumbersome and complex, resulting in high emissions and energy consumption, and the extensive use of chemical reagents is detrimental to environmental protection. Therefore, it is necessary to optimize traditional recycling processes by simplifying separation steps and reducing economic costs. Numerous patents have invented more environmentally friendly recycling technologies for waste battery materials, achieving the regeneration of lithium cobalt oxide materials through a series of treatment methods, thereby realizing a closed-loop supply of waste battery materials. Regeneration methods can be classified into indirect regeneration and direct regeneration based on the process flow.

[0004] Indirect regeneration refers to the process of decomposing waste electrodes into raw materials through a series of steps for resynthesis. For example, Chinese patent application CN 110668506 A discloses a method for recycling and regenerating lithium cobalt oxide from waste lithium-ion batteries. This method involves mixing a eutectic solvent with waste cathode material and leaching it at low temperature to obtain cobalt oxalate and lithium carbonate precipitates. After drying, grinding, and calcining, these precipitates are mixed to obtain lithium cobalt oxide. Another Chinese patent application CN 115051058 A discloses a method for recycling polyvinylidene fluoride (PVDF) and regenerating lithium cobalt oxide cathode materials from waste lithium cobalt oxide batteries. This method involves mixing waste cathode material with an organic carbon source and then performing reduction calcination. Lithium and cobalt are separated by water leaching, and then Li₂CO₃ and Co₃O₄ are obtained through evaporation crystallization and calcination, respectively. Finally, these are mixed in a stoichiometric ratio to obtain regenerated lithium cobalt oxide. While these processes avoid the use of acid and alkali reagents, they still require the decomposition of LCO to generate raw materials for resynthesis, making the process lengthy and potentially causing secondary pollution.

[0005] Direct regeneration refers to repairing the electrode directly without damaging it. This strategy effectively avoids the separation of multiple metal ions with similar chemical properties, shortens the process, and maximizes the reuse of metal elements in waste LIBs. For example, Chinese patent application CN113948787A discloses a method for recycling and regenerating retired lithium cobalt oxide batteries, which uses a solid-phase lithium replenishment method to replenish the lithium lost in the waste positive electrode, thus restoring LCO performance. Chinese patent application CN112563604A discloses a method for regenerating waste lithium-ion battery positive electrode materials. This invention achieves full and uniform lithium replenishment of waste positive electrode materials through electrolysis, combined with heat treatment to restore the material structure. Although the above technologies can achieve direct LCO regeneration, their performance can only be restored to a general level. With the continuous development of new electronic products, the demands for thinner and lighter designs and longer standby times are placing increasingly higher requirements on the energy density of battery materials. Under current industry technology, increasing voltage is the most feasible way to improve the energy density of lithium cobalt oxide (SLCO). However, due to the inherent structural limitations of SLCO, high-voltage operation can lead to side reactions and irreversible structural changes. Solving these problems has been a key research focus in the industry. Current methods include doping modification, coating modification, and electrolyte system optimization. Improving the performance of recycled materials is also a new research direction. For example, Chinese patent application CN114678616A discloses a method for recycling and regenerating waste SLCO cathode materials. Lithium isopropoxide and waste SLCO cathodes are placed in ethanol, and tantalum pentoxide, ruthenium oxide, magnesium fluoride, and TEMPO are added. Microwave treatment and repeated washing yield a lithium-modified regenerated high-voltage cathode material. However, the improvement in high-voltage cathode performance obtained by this method is not significant and fails to surpass commercial SLCO; furthermore, the doped substances lack electrochemical activity and cannot provide electrochemical performance. Therefore, to achieve reasonable recycling of SLCO and high-voltage performance regeneration, finding a reliable and efficient lithium-modification synergistic modification method for SLCO is an urgent research direction to explore.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a method for recycling and regenerating lithium cobalt oxide cathodes from spent lithium batteries. First, a pure spent lithium cobalt oxide cathode is obtained through pretreatment. Then, a solid-state remediation method is used to simultaneously replenish lithium and regenerate spinel-like LiNi. 0.5 Mn 1.5 Micro-coating with O4 material yielded directly modified and regenerated sample LNMO-SLCO.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for recycling and regenerating lithium cobalt oxide cathodes from spent lithium batteries includes the following steps: (1) After discharging the SLCO battery, manually disassemble the battery and collect the positive electrode sheet coated on the aluminum foil with SLCO. (2) SLCO active material and aluminum foil of positive electrode are separated to obtain SLCO powder; (3) The obtained SLCO powder is heat-treated in a muffle furnace to remove residual impurities and obtain pure SLCO powder; (4) Perform ICP test on the pure SLCO obtained in step (3) to obtain the lithium loss stoichiometry. Weigh a certain stoichiometric ratio of Li source for lithium replenishment, which needs to be in excess by 5wt%. Weigh a certain stoichiometric ratio of Li source, Ni source and Mn source and mix them as the precursor of LNMO coating layer. (5) Add the Li source, Ni source and Mn source weighed in step (4) to the ethanol solution and stir until completely dissolved to obtain a mixed ionic solution; (6) Add the pure SLCO powder obtained in step (3) into the PVP solution and disperse it by ultrasonication. Then add the mixed ionic solution obtained in step (5). After continuous stirring, the metal ions are uniformly adsorbed on the SLCO particles with the assistance of the viscous PVP solution. (7) The solution obtained in step (6) is dried, ground into powder, placed in a muffle furnace for calcination, and then ground and sieved to obtain the target product LNMO-SLCO with uniform particle size.

[0009] The method for separating the SLCO active material and aluminum foil in step (2) to obtain SLCO powder is as follows: a. Cut the positive electrode sheet into 3×3 cm pieces, immerse it in NMP solution and ultrasonically clean it for 5 min to dissolve soluble impurities on the surface, and dry it at 50℃-70℃ to obtain a clean positive electrode sheet. b. Transfer the electrode sheet to a crucible and place it in a muffle furnace. Calcine at 550°C for 25 minutes to remove conductive carbon black and PVDF binder. c. Place the calcined mixture in a mechanical crusher and crush for 3-5 seconds to obtain a mixture of LCO powder and aluminum shavings. Then, sieve the mixture through a 300-mesh sieve to obtain SLCO powder.

[0010] Furthermore, the heat treatment temperature in step (3) is 600°C and the heat treatment time is 1 hour.

[0011] Furthermore, in step (4), the content of the LNMO coating layer is (x) wt% of the matrix SLCO, where 2 < x < 5.

[0012] Furthermore, in step (6), the mass fraction of the PVP solution is 10%, and the ultrasonic dispersion method is as follows: firstly, ultrasonic treatment is performed for 10~20 min, and then the solution is placed on a magnetic stirrer and stirred for 1 h to further disperse the SLCO powder.

[0013] Furthermore, the sintering temperature in step (7) is 850℃~900℃, and the sintering time is 8 h.

[0014] The lithium cobalt oxide cathode obtained by the recycling and regeneration method of the lithium cobalt oxide cathode in the waste lithium battery is labeled as (x)wt% LNMO-SLCO, where 2 < x < 5.

[0015] The present invention also provides a lithium-ion battery cathode slurry, which uses the above-mentioned LNMO-SLCO as the active material.

[0016] The present invention also provides a button half-cell with a positive electrode material, using the above-mentioned LNMO-SLCO as the working electrode.

[0017] The present invention also provides a lithium-ion full battery, which uses the above-mentioned LNMO-SLCO as the positive electrode.

[0018] Mechanism of this invention: The direct recycling and high-performance regeneration method proposed in this invention abandons traditional hydrometallurgical and pyrometallurgical techniques. It employs a micro-lithium replenishment and repair synergistic coating modification technology to achieve reasonable recycling of SLCO and obtain high-voltage resistance. Surface coating modification is a common method to improve the high-voltage resistance of LCO. The electrochemical properties of the coating material and its interaction with the matrix play an important role in sustainable long-term cycling; these materials mainly include metal oxides, fluorides, and phosphates. Spinel-like cathode materials possess a three-dimensional lithium diffusion path and exhibit higher structural stability and electronic / ionic conductivity compared to other materials. Micro-coating the surface of LCO particles with spinel-like materials is a reliable method to improve the high-voltage resistance of LCO. 0.5 Mn 1.5 O4 (LNMO) is a mature high-voltage cathode material. Like other spinel materials, it exhibits high electrochemical stability, structural stability, and ionic conductivity. More importantly, LNMO possesses the same oxygen-containing face-centered cubic structure as layered LCO, potentially leading to better structural stability and compatibility with the matrix LCO. Studies of the failure mechanism of spent cathodes have revealed that after cyclic aging, the surface of LCO contains the spinel phase Co3O4 and Li vacancies, disrupting its layered structure. Therefore, to restore the performance of LCO to its original level, its layered structure needs to be repaired.

[0019] Based on this, the present invention proposes a solid-phase repair, modification, and regeneration method that simultaneously performs micro-lithiation repair on SLCO while forming a spinel LNMO interface coating on its surface. A quantitative Li source and LNMO precursor for lithium replenishment are coated onto the SLCO substrate surface using a PVP method. During the high-temperature treatment process, Li... + It diffuses into the Li vacancies, restoring the layered structure; at the same time, the LNMO precursor reacts with the LCO matrix surface to form a thin layer of spinel-like material LiNi in situ. 0.5 Mn 1.5 O4. The stable interface between the host material and the spinel coating layer promises to provide an efficient pathway for the migration of ions and electrons throughout the long-term cycling process. Simultaneously, the strong chemical / mechanical interaction between the matrix LCO and LNMO reduces particle strain, thereby stabilizing the layered structure of LCO and enabling stable cycling at 4.6V with greater capacity. This invention achieves high-voltage performance LNMO-SLCO regeneration by simultaneously performing lithium replenishment and coating modification, significantly improving the electrochemical performance of SLCO and enabling efficient resource recycling.

[0020] The beneficial effects of this invention are as follows: This invention provides a simple and feasible strategy for the recycling, modification, and reuse of cathode materials from spent lithium cobalt oxide batteries. The modified and regenerated LNMO-SLCO sample exhibits high discharge capacity and good electrochemical cycle stability. The lithium-coating modification and regeneration process not only restores the layered structure but also forms an ultrathin spinel-like material on the surface of lithium cobalt oxide. Its coating layer possesses excellent Li... + The improved conductivity enhances charge transport at the surface, forming a physical barrier layer between the positive electrode and the electrolyte, thus suppressing interfacial side reactions. The excellent high-voltage resistance demonstrates that the modified regeneration method of this invention is a promising recycling strategy. It not only provides a new and effective approach to the urgent problem of lithium battery recycling but also offers a new solution to the poor high-voltage resistance of lithium cobalt oxide materials. It directly recycles waste lithium battery positive electrode materials to generate high-value-added positive electrode materials, laying a research foundation for large-scale, orderly recycling. Specifically, this is reflected in: (1) The recycling process of this invention is short, does not require the use of harmful reagents, is environmentally friendly and low in cost; (2) High-performance regeneration of waste lithium cobalt oxide battery cathode materials has been achieved. The modified regenerated materials obtained can achieve stable cycling under high voltage, with higher discharge capacity and better cycle stability. (3) Simultaneously solve the problems of recycling of lithium cobalt oxide battery cathode material and poor high voltage resistance of lithium cobalt oxide, realize the short-process recycling of battery materials, and give full play to the highest value of recycled resources.

[0021] (4) The recycled and modified LNMO-SLCO provided by this invention has considerable reversible capacity and excellent cycling performance at a high voltage of 4.6V: A. High reversible capacity, with an initial discharge capacity and charge capacity of 212 mAh·g at a 0.1C rate. -1 and 235mAh·g -1 The first lap coulomb efficiency is 90%. B. Excellent cycling performance under high pressure; after 150 cycles at 0.5 C, it still retains 135 mAh·g. -1 The reversible capacity and capacity retention are approximately 24% higher than those of CLCO. Attached Figure Description

[0022] Figure 1 Charge-discharge curves of SLCO, CLCO and 5wt% LNMO-SLCO at 0.1C rate in half cells.

[0023] Figure 2 Cyclic stability of SLCO, CLCO and 5wt% LNMO-SLCO in half-cell after 150 cycles.

[0024] Figure 3 XRD patterns of SLCO, RLCO and 5wt% LNMO-SLCO cathode samples.

[0025] Figure 4 SEM image of a 5wt% LNMO-SLCO cathode sample.

[0026] Figure 5 The image shows the SEM-EDS pattern of a 5wt% LNMO-SLCO cathode sample. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0028] Example 1 The method for recycling and regenerating lithium cobalt oxide cathodes from spent lithium batteries in this embodiment is as follows: 1. SLCO batteries recovered from 3C electronic devices are completely discharged in a 20-40 wt% NaCl solution until the battery voltage drops below 1V to ensure safe disassembly; 2. Manually disassemble the battery, separate the aluminum-plastic casing, positive and negative electrode plates, separator, etc., and collect the positive electrode plates coated with SLCO on the aluminum foil; 3. Separate the SLCO active material and aluminum foil from the positive electrode, as follows: (1) Cut the positive electrode sheet into approximately 3×3 cm pieces, immerse it in NMP solution and ultrasonically clean it for 5 min to dissolve soluble impurities on the surface, and dry it at 50℃-70℃ to obtain a clean positive electrode sheet; (2) Transfer the electrode sheet to a crucible and place it in a muffle furnace, calcine it at 550℃ for 25 min to remove conductive carbon black and PVDF binder; (3) Place the calcined mixture in a mechanical crusher and crush it for 3~5 s to obtain a mixture of LCO powder and aluminum scrap; (4) Since the aluminum scrap and powder have different particle sizes after crushing, they can be sieved through a 300-mesh sieve to obtain SLCO powder.

[0029] 4. The obtained SLCO powder is then heat-treated in a muffle furnace at 600℃ for 1 hour to remove residual impurities and obtain pure SLCO. 5. Perform ICP testing on the obtained SLCO to obtain the lithium loss stoichiometry. Weigh out a certain stoichiometric ratio of Li source for lithium replenishment, requiring an excess of 5 wt%. Weigh out a certain stoichiometric ratio of Li source, Ni source, and Mn source to mix as the precursor for the coating layer LNMO, with the LNMO content of the coating layer being 5 wt% of the matrix SLCO. 6. Add all the modified materials weighed in step 5 to the ethanol solution and stir until completely dissolved to obtain a mixed ionic solution; 7. Dissolve polyvinylpyrrolidone (PVP) in distilled water at a weight ratio of 10%, and add SLCO powder to the PVP solution. First, sonicate for 10-20 min, then stir on a magnetic stirrer for 1 h to further disperse the SLCO powder. Then add the mixed ionic solution obtained in step 6, and after continuous stirring, the metal ions are uniformly adsorbed onto the SLCO particles with the assistance of the viscous PVP solution. 8. Heat the above solution to 80℃ to completely evaporate the solvent until it becomes a dry gel. Dry it thoroughly in a 120℃ forced-air drying oven. Then grind the dried precursor into powder for 15 min. Place it in a muffle furnace and heat it to 850℃~900℃ for 8 h. After cooling in the furnace, grind it again for 15 min and sieve to obtain the target product with uniform particle size. Based on the LNMO content of the coating layer, the obtained lithium-modified sample is labeled as 5wt% LNMO-SLCO.

[0030] Example 2 Preparation of lithium-ion battery positive electrode slurry: 5wt% LNMO-SLCO was used as the active material, polyvinylidene fluoride (PVDF) as the binder, and conductive carbon black (Super P) as the conductive agent. The mixture was ground in an agate mortar at a mass ratio of 8:1:1. After grinding the three materials evenly, they were mixed with N-methyl-2-pyrrolidone (NMP) solution and magnetically stirred for 3 h until the slurry was uniformly mixed. The slurry was evenly coated onto aluminum foil using a coating machine to a coating thickness of 150 μm. The electrode sheets were first dried in a forced-air drying oven for 4 h, and then dried in a vacuum drying oven at 120℃ for 12 h. Subsequently, rolling, cutting, and weighing were performed.

[0031] Example 3 Coin cells with a 5wt% LNMO-SLCO cathode material were assembled, and charge-discharge curves and long-cycle tests were performed within the 2.8–4.6 V cutoff voltage range. Electrochemical evaluation of the modified cathode material was conducted using assembled coin cells (CR2032). The entire assembly process was carried out in an argon-filled glove box, where the water and oxygen levels were all less than 0.1 ppm. A 5wt% LNMO-SLCO electrode was used as the working electrode, and a lithium sheet was used as the counter electrode. The electrolyte consisted of 1 M lithium hexafluorophosphate (LiPF6) dissolved in a 1:1 volume ratio of ethylene carbonate (EC) and diethyl carbonate (DEC). A Celgard lithium-ion battery separator was used. Electrochemical performance tests were conducted using the LANHE testing system, with a charge-discharge voltage range of 2.8–4.6 V and test current densities of 0.1C and 0.5C.

[0032] Example 4 A lithium-ion full battery was prepared. Graphite was used as the negative electrode, 5wt% LNMO-SLCO was used as the positive electrode, 1 M LiPF6 was dissolved in EC and DEC solvents in a volume ratio of 1:1, and Celgard membrane was used as the separator.

[0033] The electrochemical performance of lithium-ion half-cells assembled using SLCO, commercial lithium cobalt oxide (CLCO), and LNMO-SLCO as LIB cathodes was tested in the LANHE Blue Electricity testing system using constant current charge-discharge technology. The charge-discharge voltage range was 2.8-4.6V, and the test temperature was 30℃. Charge-discharge cycles at a current density of 0.1C were performed as follows: Figure 1 As shown, the SLCO's first-cycle discharge capacity is only 154 mAh·g. -1 The first-cycle discharge capacities of LNMO-SLCO and CLCO are 215 mAh·g, respectively. -1 and 212 mAh·g -1 This demonstrates that the initial capacity of the regenerated cathode, after lithium supplementation modification, was restored.

[0034] In addition, the cycle stability of the cathode before and after modification was tested after 150 cycles at 0.5C rate, such as... Figure 2 As shown, LNMO-SLCO retained 72.20% of its capacity after 150 cycles, while SLCO and CLCO retained only 49.46% and 48.23%, respectively. This demonstrates that lithium supplementation modification and regeneration can significantly improve the high-voltage resistance of the cathode and enhance the cycling stability of lithium cobalt oxide under high voltage. Figure 3 The X-ray diffraction (XRD) results showed that the lattice parameters of SLCO, RLCO (lithium-only regenerated cathode) and LNMO-SLCO samples were highly consistent during the lithium replenishment and coating modification process, with good crystal form and no impurity peaks. It was determined that this trace surface modification had a weak effect on the LCO layered material itself, and no impure phase was generated after lithium replenishment and coating modification.

[0035] This invention presents a simple and feasible strategy for the recycling, modification, and reuse of cathode materials from spent lithium cobalt oxide batteries. The modified and regenerated LNMO-SLCO sample exhibits high discharge capacity and good electrochemical cycling stability. The lithium-coating modification and regeneration process not only restores the layered structure but also forms an ultrathin spinel-like material on the surface of lithium cobalt oxide. Figure 4 and Figure 5 ).

[0036] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for recycling and regenerating lithium cobalt oxide cathodes from waste lithium batteries, characterized in that... Includes the following steps: (1) After discharging the SLCO battery, manually disassemble the battery and collect the positive electrode sheet coated on the aluminum foil with SLCO. (2) SLCO active material and aluminum foil of positive electrode are separated to obtain SLCO powder; (3) The obtained SLCO powder is heat-treated in a muffle furnace to remove residual impurities and obtain pure SLCO powder; (4) Perform ICP test on the pure SLCO obtained in step (3) to obtain the lithium loss stoichiometry. Weigh a certain stoichiometric ratio of Li source for lithium replenishment, which needs to be in excess by 5wt%. Weigh a certain stoichiometric ratio of Li source, Ni source and Mn source and mix them as the precursor of LNMO coating layer. (5) Add the Li source, Ni source and Mn source weighed in step (4) to the ethanol solution and stir until completely dissolved to obtain a mixed ionic solution; (6) Add the pure SLCO powder obtained in step (3) into the PVP solution and disperse it by ultrasonication. Then add the mixed ionic solution obtained in step (5). After continuous stirring, the metal ions are uniformly adsorbed on the SLCO particles with the assistance of the viscous PVP solution. (7) The solution obtained in step (6) is dried, ground into powder, placed in a muffle furnace for calcination, and then ground and sieved to obtain the target product LNMO-SLCO with uniform particle size; In step (4), the content of the LNMO coating layer is between 2-5 wt% of the SLCO matrix; The method for separating the SLCO active material and aluminum foil in step (2) to obtain SLCO powder is as follows: a. Cut the positive electrode sheet into 3×3 cm pieces, immerse it in NMP solution and ultrasonically clean it for 5 min to dissolve soluble impurities on the surface, and dry it at 50℃-70℃ to obtain a clean positive electrode sheet. b. Transfer the electrode sheet to a crucible and place it in a muffle furnace. Calcine at 550°C for 25 minutes to remove conductive carbon black and PVDF binder. c. Place the calcined mixture in a mechanical crusher and crush it for 3-5 seconds to obtain a mixture of SLCO powder and aluminum shavings. Then, sieve it through a 300-mesh sieve to obtain SLCO powder. The heat treatment temperature in step (3) is 600℃ and the heat treatment time is 1 hour; The mass fraction of the PVP solution in step (6) is 10%. The ultrasonic dispersion method is as follows: first, ultrasonic treatment for 10~20 min, then stirring on a magnetic stirrer for 1 h to further disperse the SLCO powder. The sintering temperature in step (7) is 850℃~900℃, and the sintering time is 8 h.

2. A lithium-ion battery cathode slurry, characterized in that: The LNMO-SLCO described in claim 1 is used as the active material.

3. A button half-cell with a positive electrode material, characterized in that: The LNMO-SLCO described in claim 1 is used as the active material for the working electrode.

4. A lithium-ion full battery, characterized in that: The LNMO-SLCO described in claim 1 is used as the active material for the positive electrode.

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