Investigation Of Synthesis?modification And Electrochemical Performance Of Lithium Zinc Titanate As Anode Material For Lithium Ion Batteries

Spinel Li₂ZnTi₃O₈ as a kind of anode materials of lithium ion batteries has attracted much attention from many researchers,because of its excellent cycle stability,high specific capacity and low cost.For optimizing the process of synthesizing Li₂ZnTi₃O₈ and improving the electrochemical behaviors of Li₂ZnTi₃O₈ through coating carbon method,solid-state reaction was chose and the influence of the syntheses technologic parameters and coating conditions are explored.Firstly,the pure Li₂ZnTi₃O₈ samples have been synthesized by solid-state reaction,and two conditions include calcinations temperature and roasting time were investigated.The results showed that the pure well-crystallized Li₂ZnTi₃O₈ can be prepared by roasting the precursor at 750?for 4 h.The changing of the roasting time and temperature cannot change the composition of the production.The sample roasted at 750?for 4 h showed a high initial capacity of 192 mAh/g at a rate of 2 C,and still had 191.3 mAh/g after 50cycles.Secondly,the carbon coated Li2ZnTi3O8 samples using glucose as carbon source was synthesized by the solid-state reaction,the pre-coating method was used.The best carbon content was investigated.The results showed that,carbon coating can improve the electrochemical behaviors significantly,and the sample which carbon content was 5.98%showed the best electrochemical behaviors.At the rate of 5 C,its initial discharge capacity was 232 mAh/g,after 100 cycles,199.9 mAh/g was still remained.Carbon coating can not only decrease the polarization during the charge/discharge reactions,but also improve the conductivity of the materials.At last,the N-doped carbon-coated Li2ZnTi3O8 anode material was fabricated with chitin as the carbon source by pre-coating process via a facile solid-state reaction method.The N-doped carbon-coated Li₂ZnTi₃O₈?NC-LZTO?samples show the significant improvement in rate capability compared with carbon coated Li₂ZnTi₃O₈?C-LZTO?sample derived from glucose and naked Li₂ZnTi₃O₈?LZTO?sample.After 200 cycles at 2C,its capacity retention is 98.7%.The increased electrochemical performance of NC-LZTO can be ascribed to the larger specific surface,smaller particle size and better electronic conductivity.