Preparation Of LiNi_0.83Co_0.11Mn_0.06O₂ Cathode Material And Its Surface Modification In Non-aqueous System

The nickel-rich layered cathode material has the advantages of high specific capacity and low cost,and has been one of the widely used material in the field of power batteries.However,its inherent shortcoming such as poor cycling performance,limits its further application.In this paper,the Li Ni_0.83Co_0.11Mn_0.06O₂ cathode material was prepared by sintering the mixture of commercial precursors Ni_0.83Co_0.11Mn_0.06（OH）₂ and Li OH·H₂O.Then,Li₂WO₄ and Ce O₂ were used respectively to modify the surface by wet chemical techniques in non-aqueous solution system.The main contents are as follows:The effects of preparation parameters（sintering temperature,the ratios of lithium and sintering time）on the structure,morphology and electrochemical performance of nickel-rich layered ternary cathode materials Li Ni_0.83Co_0.11Mn_0.06O₂ are studied.When the sintering temperature is 750℃,the ratio of lithium and transition-metal in the precursor is 1.05,and the sintering time is 15 h,the obtained material displays the best electrochemical performance.Within the voltage range of2.8～4.3 V,the first discharge specific capacity at 1 C was 184.8 m Ah g^-1,anf the capacity retention after 200 cycles is 84.9%.Additionally,the discharge specific capacity at a rate of 5 C was 152.5 m Ah g^-1.Respectively,Li₂WO₄ and CeO₂ are coated on the surface of the material by wet coating in non-aqueous solution system.The first discharge specific capacity of material decreases after Li₂WO₄ coating modified,but the cycling performance is greatly improved.When the mass of the coating substance is 0.5 wt.%,the material owns the best electrochemical performance.The capacity retention after 200 cycles at a rate of 1 C is as high as 93.5%,and the discharge specific capacity at a rate of 5 C is 162.7m Ah g^-1.The Ce O₂ coating layer presents discontinuous"island"shape,which still greatly improves the electrochemical performance of the material.When the mass of the coating substance is 0.5 wt.%,the material owns the best electrochemical performance,and the capacity retention after200 cyclys at a rate of 1 C is 92.8%.The discharge specific capacity at a rate of 5 C is 160 mAh g^-1.