The Research Of Novel Li₂TiO₃-carbon Anode Materials

Monoclinic lithium metasilicate?Li₂TiO₃?has a stable crystal structure and a three-dimensional lithium ion diffusion channel,but it is almost an electronic insulator.This research work mainly combines Li₂TiO₃ with carbon materials,and uses the excellent conductive properties of carbon materials to prepare a new lithium ion battery anode material with excellent conductivity and lithium ion conductivity.In this work,the Li₂TiO₃-carbon?LTOC?anode material was prepared by a simple high temperature solid phase reaction.When the carbon source is petroleum coke,the influence of temperature and petroleum coke content on the electrochemical performance of the negative electrode material is mainly explored.Studies have shown that when the sintering temperature is 850°C,the crystal growth of Li ₂TiO₃ in the material is relatively complete and has good electrochemical performance.The LTOC?prepared at 850°C?sample has a capacity of 231 mAh/g at a current density of0.1 A/g.LTOC has good cycle life performance,and has a specific capacity of 200mAh/g after charging/discharging 500 cycles at a current density of 0.3 A/g,and the capacity retention rate is 95%.Based on the optimal temperature,the electrochemical properties of the electrode materials were investigated by changing the petroleum coke content.The results show that LTOC-3?the petroleum coke content is 73.5wt%?is the best electrochemical synthesis product.Its stable discharge capacity is 279mAh/g at a current density of 0.1 A/g,and the first efficiency is 62%.The initial capacity of the LTOC-3 material at a high current density of 0.3 A/g is 264 mAh/g.After 1000 cycles,the battery capacity is still 245 mAh/g,and the capacity retention rate is 93%.The lithium ion diffusion coefficients of LTOC-3 used in the oxidation and reduction processes were calculated by cyclic voltammetry curves to be1.618×10^-8 cm²/s and 2.083×10^-9 cm²/s,respectively.Secondly,the effects of different carbon sources on Li₂TiO₃ composites were further explored.The results show that the LTO-FSN?FSN is a commercial carbon material?sample has the highest initial discharge efficiency of 65%and has good rate performance.The LTO-FSN sample material has excellent cycle life performance with an initial capacity of 297 mAh/g at a high current density of 0.3 A/g and a capacity of 292 mAh/g after 1000 cycles,with only a loss of 5 mAh/g,the capacity retention rate is 98%.In summary,the LTOC anode material is an ideal and promising anode material for lithium ion batteries.