摘要
以Li_2CO_3、锐钛矿TiO_2和石墨烯为原料,采用固相球磨及喷雾干燥相结合的方法制备钛酸锂和钛酸锂/石墨烯复合负极材料。用X射线衍射(XRD)、拉曼光谱、扫描电子显微镜(SEM)表征了样品的晶体结构及形貌。通过恒流充放电测试样品的电化学性能,考察不同石墨烯添加量对钛酸锂材料电化学性能的影响。当石墨烯添加量质量分数为1%时,钛酸锂/石墨烯复合负极材料(LTO-G-2)具有优异的倍率性能及循环稳定性。在0.2C、0.5C、1C、3C、5C和10C倍率下的充电比容量为172.9mA·h/g、165.7mA·h/g、163.5mA·h/g、157.4mA·h/g、154.0mA·h/g和143.5mA·h/g。5C倍率下经历200次循环,容量保持率为94.8%。循环伏安测试(CV)表明LTO-G-2样品的极化程度是最小的。交流阻抗测试(EIS)结果显示LTO-G-2的电荷转移阻抗(69.6Ω)小于纯的钛酸锂的电荷转移阻抗(140.5Ω)。
Li4Ti5O12 and Li4Ti5O12 /graphene composite have been successfully prepared by a solid-state ball milling and spray drying method using Li2CO3, TiO2 and graphene as starting materials. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy were used to confirm the structure and morphology of the materials. The effects of the amount of graphene on the electrochemical properties of Li4Ti5O12 were investigated by the galvanostatic charge-discharge tests. When 1% graphene was added, the Li4Ti5O12/graphene composite (LTO-G-2) exhibited excellent performance with the charge capacities of 172.9mA·h/g, 165.7mA·h/g, 163.5mA·h/g, 157.4mA·h/g, 154.0mA·h/g and 143.5mA·h/g at rates of 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively. Moreover, LTO-G-2 showed a charge capacity retention of 94.8% after 200 cycles at a rate of 5C. Cyclic voltammetry tests (CV) showed that LTO-G-2 had the smallest polarization. Electrochemical impedance (EIS) tests showed that the charge transfer resistance of LTO-G-2 (69.6Ω) was lower than that of neat LTO (140.5Ω).
作者
张利辉
徐宇兴
刘振法
魏爱佳
李文
ZHANG Lihui;XU Yuxing;LIU Zhenfa;WEI Aijia;LI Wen(State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences,Beijing 100190, China;Institute of Energy Resources, Hebei Academy of Sciences, Shijiazhuang 050081, Hebei, China;Zhongke Langfang Institute of Process Engineering, Langfang 065001, Hebei, China;University of Chinese Academy ofSciences, Beijing 100049, China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2019年第2期949-955,共7页
Chemical Industry and Engineering Progress
基金
河北省重点基础研究(17964407D)
河北省科技计划(17394411D
16294403D)
关键词
固相球磨
喷雾干燥
钛酸锂
石墨烯
负极材料
solid-state ball milling method
spray drying
lithium titanate
graphene
anode material
