Regeneration Of Spent LiFePO4cathode Materials And Synthesis Of LiNi_0.8Mn_0.1Co_0.1O₂

With extensive application of LiFePO4batteries，the problem in dealing and recyclingis being outstanding. Compared with traditional dealing method, which concentrated onrecycling metal with acid and base solution, in this paper, we concentrated more on therecycle and regeneration processes of cathode material. At the same time, the fastdevelopment of HEV and EV picked up more request in capacity of lithium batteries,layer LiNi0.8Co0.1Mn0.1O2was then investigated by people for its high capacity.In this paper, we picked up a solvothermal method based on traditional coprecipitation,which can obtain homogeneous product. We also investigated its related properties.Through sorting operation, high quality spent LiFePO4was obtained feasibility andeffectiveness by dipping it in base solution with commercial LiFePO4batteries.Solvothermal method was developed to regenerate spent LiFePO4cathode materials.After regeneration, the capacity of material was promoted from110mAh g-1to130mAh g-1. On the other hand, the rate performance was improved visibly; the materialdemonstrated69.44and56.02mAh g-1even at10and15C. The regenerated materialalso exhibited better cyclic performance after100cycles and the discharge capacityretention rate was99.6%at1C.We also investigated properties of Li3Fe2(PO4)3material, which was obtained bysintering spent LiFePO4with heat treatment. Electrochemical result indicatedthe new material display discharge capacity of71.45mAh g-1. After50cycles, thematerial exhibited discharge capacity retention rate of90.1%and91.5%at0.5C and1.0C, respectively.On the other hand， we investigated the synthesis and related properties ofLiNi0.8Co0.1Mn0.1O2material. With CO(NH2)2as precipitation, uniformhierarchical precipitation was obtained by hydrothermal and solvothermalmethod. Test electrochemical properties，final material obtained by solvothermalmethod was better than using hydrothermal, which demonstrated initialcoulombic efficiency of83.6%, initial discharge capacity of194.6mAh g-1, after50cycles, the discharge capacity retention rate was88.7%at0.5C.