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采用溶胶-凝胶法制备Li4/3Ti5/3O4/Ag复合材料,通过X射线衍射、扫描电子显微镜、恒电流充放电及交流阻抗等技术检测和分析合成产物的物相、形貌及电化学性质。研究表明,在Li4/3Ti5/3O4中添加Ag后Li4/3Ti5/3O4的Ti—O键没受影响,Li4/3Ti5/3O4/Ag及Li4/3Ti5/3O4的晶格常数非常接近,Ag没有进入Li4/3Ti5/3O4晶格,只是均匀地分散在Li4/3Ti5/3O4颗粒中。与Li4/3Ti5/3O4相比,Li4/3Ti5/3O4/Ag复合材料具有更高的比容量,更高的库仑效率以及更低的极化。添加Ag后对Li4/3Ti5/3O4锂离子扩散系数影响不大。电化学循环过程中,Li4/3Ti5/3O4/Ag的容量损失小于Li4/3Ti5/3O4,且随着充放电倍率的增加两者容量损失差距变大。Ag的添加大大地改善了Li4/3Ti5/3O4的循环性能,尤其是大电流循环性能。
Li4 / 3Ti5 / 3O4 / Ag composites were prepared by sol-gel method. The phase, morphology and electrochemical properties of the synthesized products were characterized by X-ray diffraction, scanning electron microscopy, galvanostatic charge- . The results show that the Ti-O bond of Li4 / 3Ti5 / 3O4 is not affected when Ag is added to Li4 / 3Ti5 / 3O4. The lattice constants of Li4 / 3Ti5 / 3O4 / Ag and Li4 / 3Ti5 / 3O4 are very close and Ag does not enter Li4 / 3Ti5 / 3O4 lattice, but uniformly dispersed in Li4 / 3Ti5 / 3O4 particles. Compared with Li4 / 3Ti5 / 3O4, Li4 / 3Ti5 / 3O4 / Ag composites have higher specific capacity, higher coulombic efficiency and lower polarization. The addition of Ag has little effect on the Li4 / 3Ti5 / 3O4 lithium ion diffusion coefficient. During the electrochemical cycling, the capacity loss of Li4 / 3Ti5 / 3O4 / Ag is less than that of Li4 / 3Ti5 / 3O4, and the difference of capacity loss between the two becomes larger as the charge-discharge ratio increases. The addition of Ag greatly improves the cycle performance of Li4 / 3Ti5 / 3O4, especially the high current cycling performance.