溶胶-喷雾干燥法制备纳米Li3V2(PO4)3/C及其电化学性能

本文以LiOH.H2O、NH4VO3、H3PO4和柠檬酸为原料,采用溶胶-喷雾干燥法制备Li3V2(PO4)3/C正极材料,对比了喷雾前驱体直接煅烧与机械活化后煅烧的样品的结构、形貌及其电化学性能。采用XRD、SEM、BET和振实密度测试等对样品的结构、形貌等进行了表征;采用恒流充放电、CV和EIS等手段考察了材料的电化学性能。结果表明,溶胶-喷雾干燥得到的样品为多孔球壳形,其壳体由厚度为100 nm左右的纳米片组成,经机械活化后煅烧保持保持了其纳米片结构,其结晶度与振实密度改善较明显,电化学性能较优异。0.1C放电比容量为123.6 mAh.g-1,10C和20C高倍率放电比容量还高达107.8和106.0 mAh.g-1。电化学阻抗结果表明,由该方法制备的样品具有较小的电荷转移阻抗。

Synthesis and Electrochemical Performance of Nano-Structure Li3V2(PO4)3/C by Sol-Spray Drying Method

Li₃V₂(PO₄)₃/C samples were successfully synthesized by sol-spray drying method, with LiOH·H₂O, NH₄VO₃, H₃PO₄ and critic acid as raw materials, comparing the effect of mechamicalactivation before calcinations and direct calcination on the structure, morphology and electrochemical properties of the samples. The structure and morphology were characterized by XRD, SEM, BET and tap density test, and the electrochemical performance was studied by galvanostatic charge-discharge test, CV and EIS. The results show the samples are hollow spherical shell shape, which is composed of nano-sheet about 100nm and still keep the structure after mechamicalactivation. However, the crystallinity and tap density have improved a lot, so is the electrochemical performance. The discharge capacity is 123.6 mAh·g^-1 at 0.1C, maintaining 107.8 and 106.0 mAh·g^-1 even at high discharge rate of 10C and 20C. The EIS results indicate the samples prepared by the method have a smaller charge transfer resistance.