氟掺杂对钛酸锂负极材料性能的影响

Effect of F-doping on properties of lithium titanate anode materials

选用水热法制备了F掺杂的钛酸锂材料(LTO)。通过X射线衍射(XRD)、扫描电子显微镜分析(SEM)、透射电子显微镜分析(TEM)、X射线光电子能谱分析(XPS)、电化学性能测试等测试方法探究了F掺杂对LTO作为电极材料在电化学性能方面的影响。根据粒径结构最优原则(电极材料与电解液接触最多),获得电化学性能最佳的最优F掺杂量为0.01。在1 C倍率下,0.01F样品的比容量为218.88 mAh/g,200次循环后为202.15 mAh/g,容量保留率为93.27%,高于纯钛酸锂的85.40%;500次循环后,容量保留率为88.74%,优于纯钛酸锂的66.16%。研究结果表明,F掺杂降低了材料的电荷转移电阻,提高了锂离子扩散速率及材料的电化学性能。

F-doped lithium titanate(LTO)was prepared by hydrothermal method.The effect of F doping on the electrochemical performance of LTO as electrode material was investigated by XRD,SEM,TEM,XPS and electrochemical performance test.According to the principle of optimal particle size structure(maximum contact between electrode material and electrolyte),the optimal F doping amount of electrode material with the best electrochemical performance is 0.01.At 1 C ratio,the specific capacity of 0.01 F sample was 218.88 mAh/g and 202.15 mAh/g after 200 cycles,and the retention rate was 93.27%,which was higher than 85.40%of the pristine LTO.After 500 cycles,the capacity retention rate was 88.74%,higher than the 66.16%of the pure one.The results show that F doping decreases the charge transfer resistance,increases the diffusion rate of lithium ions and improves the electrochemical performance of the material.