Research On Recovery And Reuse Process Of Ncm Cathode Material From Spent Libs

Lithium-ion batteries have been widely used in various fields due to their excellent performance.The battery consumption has increased explosively and brought about a surge in spent batteries.The recycling of these spent batteries is an urgent problem.The spent battery ternary cathode material(NCM)material is rich in valuable metal elements such as Ni,Co,Mn,Li,etc.Reasonable recycling can not only avoid environmental pollution,save resources,but also bring huge economic benefits and conduciving to the sustainable development of the energy industry.In this paper,the waste ternary cathode material was used as raw material,and the solution of Li+,Co2+,Ni2+and Mn2+ions was obtained by reducing and acid leaching,which was directly applied to the preparation of ternary cathode material precursor and ternary cathode material,and the phosphate was investigated.The properties of the modified ternary cathode material.The obtained cathode materials were characterized by XRD,SEM,HRTEM and other analytical methods.The electrochemical properties of the materials were investigated.The main research work of the thesis are as follow:1.The ternary cathode material of waste battery was acid-leached and reduced by H2SO4-H2O2 system.By investigating factors such as acid leaching time,H2O2 addition amount,leaching temperature and acid addition ratio,the optimized leaching process conditions successfully realized Co,Ni and Mn leaching,the total leaching rate can reach more than 99.9%,and the purification technology of the leachate is studied,and the battery-level raw material standard is reached.2 The preparation of ternary cathode material precursor by coprecipitation of purified reductive acid leachate was studied.The process conditions of preparing lithium carbonate from the.filtrate of precursor were studied,and the preparation of LiNi1/3CO1/3Mn1/3O2 from precursor and lithium carbonate by solid phase reaction were further studied.The experimental results show that the total recovery rate of Li can reach over 95%.The obtained LiNi1/3Co1/3Mn1/3O2 cathode material has uniform element distribution and good crystal form.The initial discharge capacity of obtained LiNi1/3Co1/3Mn1/3O2 cathode material is 153.3 mAh·g-1,and the coulombic efficiency is 87.9%,and 93.21%specific capacity remains after 50 charge and discharge cycles.3 The phosphate doping modification technology of the prepared ternary cathode material was researched.The structural characterization proves that PO43-successfully entered the LiNi1/3Co1/3Mn1/3O2 lattice and improved the unit structure.Electrochemical characterization showed that the initial discharge capacity of the resynthesized NCM material cathode material dopped by 2%NH4H2PO4 rasises to 160 mAh·g-1 and the coulombic efficiency reaches 88.89%.The capacity retention rate reaches 90.43%after charge-discharged at 1 C for 40 cycles.The dopping of an appropriate amount of PO43-can improve the capacity and the coulombic efficiency of the positive electrode material,but excessive phosphate doping will cause obvious capacity loss and adverse effect on the cycle performance of the material.