锂离子电池负极材料 Na2Li2Ti6O14的嵌脱锂过程动力学研究

为了研究钛酸钠锂(Na2Li2Ti6O14)负极材料嵌脱锂的动力学行为,用溶胶-凝胶法合成 Na2Li2Ti6O14负极材料,采用 X 射线衍射法(XRD)和电子显微镜(SEM)分别对材料进行物相分析和微观形貌的观察.采用恒流充放电测试、循环伏安法(CV)和恒电流间歇滴定法(GITT)研究了 Na2Li2Ti6O14的电化学性能和嵌脱锂过程动力学.研究结果表明,制备的 Na2Li2Ti6O14材料纯度高,结晶度良好,循环稳定性好;由不同扫描速率的循环伏安法测出的 Na2Li2Ti6O14中锂离子在氧化、还原峰对应的化学扩散系数 Da和 Dc分别为7.3×10-11和7.8×10-11cm2/s;由恒电流间歇滴定技术测得的锂离子在 Na2Li2Ti6O14电极中的扩散系数为10-11~10-8cm2/s.

Investigation of electrochemical kinetics of Li-ion in Na2Li2Ti6O14 anode for lithium ion batteries

In order to investigate the electrochemical kinetics of Li-ion in Na2Li2Ti6O14materials for lithium ion batteries.Na2Li2Ti6O14anode materials have been synthesized by sol-gel method in this work.The sample was characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).The electrochemical performance and kinetics of Na2Li2Ti6O14were investigated by galvanostatic charge-discharge test,cyclic voltammetry(CV) and galvanostatic intermittent titration technique(GITT).The results show that the pure and crystallized Na2Li2Ti6O14delivers good cycle performance.The Daand Dcof diffusion coefficients of Li-ion in Na2Li2Ti6O14are 7.3×10-11cm2/s and 7.8×10-11cm2/s in oxidation and reduction peaks respectively by CV,and the diffusion coefficients of Li-ion in Na2Li2Ti6O14are in the range of 10-11-10-8cm2/s by GITT method.