Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3复合负极材料的制备及其性能*

Preparation and Characterization of Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3 Composite

摘要:

采用溶胶-凝胶法合成Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3复合负极材料，通过X射线衍射、扫描电子显微镜、恒电流充放电、循环伏安和电化学阻抗研究复合材料的结构、形貌及电化学性能。结果表明：溶胶-凝胶法能合成纯相Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3复合负极材料，所合成材料颗粒均匀。与纯相Li4Ti5O12相比，引入Li1.3Al0.3Ti1.7(PO4)3的Li4Ti5O12复合负极材料具有更低的锂离子嵌入/脱出阻抗，Li1.3Al0.3Ti1.7(PO4)3质量分数为1%、2%、3%、4%、5%的Li4Ti5O12复合材料首次放电容量比纯相Li4Ti5O12分别提高了6.2%、11.8%、15.5%、8.0%和2.0%。Li1.3Al0.3Ti1.7(PO4)3质量分数为3%的Li4Ti5O12复合负极材料20次循环后每次循环容量衰减率为0.022%，循环性能最好。

Abstract:

Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3 composite was synthesized by sol-gel method. The structure, morphology and electrochemical performance of the composite were studied by X-ray diffractometry, scanning electron microscopy, galvanostatic charge-discharge test, cyclic voltammeter and electrochemical impedance spectroscopy techniques. Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3 composite can be prepared by sol-gel technique and the particles of the composite are uniform. Compare with pure Li4Ti5O12, the Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3 composite has lower Li insertion/extraction impedance. The specific capacity of the Li4Ti5O12/Li1.3Al0.3Ti1.7(PO4)3 composite doped with 1 wt%, 2 wt%, 3 wt%, 4 wt% and 5% wt% Li1.3Al0.3Ti1.7(PO4)3 is 6.2%, 11.8%, 15.5%, 8.0% and 2.0% higher than the pure Li4Ti5O12，respectively. The composite doped with 3 wt% Li1.3Al0.3Ti1.7(PO4)3 shows the best cycling performance of 0.022% capacity loss per cycle.