Li_4Ti_5O_(12)/(Cu+C)复合材料的制备及电化学性能

Synthesis and Electrochemical Performance of Li_4Ti_5O_(12)/(Cu+C) Composite Electrode Material

以Li4Ti5O12,Cu(CH3COO)2.H2O和C6H12O6为前驱体,化学沉积与热分解结合合成锂离子电池负极材料Li4Ti5O12/(Cu+C)。采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、恒流充放电、循环伏安和电化学阻抗方法表征样品的结构、形貌和电化学性能。结果表明,Li4Ti5O12表面包覆的Cu与C提高了Li4Ti5O12电极材料的导电率,其循环性能和倍率性能得到有效地改善。在0.5C、1C和3C倍率下,经过50次充放电循环,放电比容量分别为168.2、160、140.6 mAh.g-1,其容量保持率分别为88.7%、84.4%、71.2%。电化学阻抗测试表明,表面包覆的Cu与C使其电荷转移阻抗大幅度减少。

Li4Ti5O12/（Cu＋C） composite as anode material for lithium-ion batteries was synthesized by chemical deposition combined with thermal decomposition of a mixture of Cu（CH3COO）2·H2O,C6H12O6 and Li4Ti5O12.The structure,morphology and electrochemical performance of samples were characterized by X-ray diffractometry（XRD）,scanning electron microscopy（SEM）,galvanostatic charge-discharge test,cyclic voltammeter（CV） and electrochemical impedance spectroscopy（EIS）.The results showed that surface coating of Cu and C on Li4Ti5O12 particle improved its electronic conductivity and therefore enhanced the performance of the circulation and ratecapability.The discharge capacity of the composite were 168.2,160 and 140.6 mAh·g^-1 at 0.5C,1C and 3C rateafter 50 cycles,and the corresponding capacity retention were 88.7%,84.4% and 71.2%,respectively.EIS test proved that surface coating of Cu and C on Li4Ti5O12 particle could decrease its charge transfer resistance greatly.