CAJ | 학술논문

采用碳热还原辅助溶胶-凝胶法合成了锂二次电池正极材料LiVPO4F/C,探讨煅烧温度和煅烧时间对所制备材料纯度、结构和电化学性能的影响.采用X射线衍射(XRD),扫描电子显微镜(SEM),恒流充放电,电化学阻抗谱(EIS)和循环伏安(CV)等手段对不同煅烧温度和时间所得的材料进行结构表征和电化学性能测试.当煅烧时间为4 h时,温度为450°C时,能够得到纯相LiVPO4F/C,在0.1C、0.5C和1.0C倍率下,电池放电比容量分别为193.2、175.6和173.7 mAh?g-1.随着煅烧温度升高, Li3V2(PO4)3杂相逐渐增多,650°C煅烧后的材料Li3V2(PO4)3成为主相.优化煅烧时间也能够有效控制Li3V2(PO4)3杂相的生成,能得到电化学性能良好的LiVPO4F/C.当煅烧温度为550°C时,反应3 h后得到的产物综合电化学性能最优.
채용탄열환원보조용효-응효법합성료리이차전지정겁재료LiVPO4F/C,탐토단소온도화단소시간대소제비재료순도、결구화전화학성능적영향.채용X사선연사(XRD),소묘전자현미경(SEM),항류충방전,전화학조항보(EIS)화순배복안(CV)등수단대불동단소온도화시간소득적재료진행결구표정화전화학성능측시.당단소시간위4 h시,온도위450°C시,능구득도순상LiVPO4F/C,재0.1C、0.5C화1.0C배솔하,전지방전비용량분별위193.2、175.6화173.7 mAh?g-1.수착단소온도승고, Li3V2(PO4)3잡상축점증다,650°C단소후적재료Li3V2(PO4)3성위주상.우화단소시간야능구유효공제Li3V2(PO4)3잡상적생성,능득도전화학성능량호적LiVPO4F/C.당단소온도위550°C시,반응3 h후득도적산물종합전화학성능최우.
LiVPO4F/C, as a cathode material of lithium-ion batteries, was prepared by carbon thermal reduction assisted sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge-discharge cycles, cyclic voltammogram (CV), and electrochemical impedance spectroscopy (EIS) were employed to investigate the effects of sintering time and temperature on the structure and corresponding electrochemical performance of as prepared materials. At a sintering time of 4 h, pure phase LiVPO4F/C material was obtained when the temperature is settled at 450 ° C. The as-produced LiVPO4F/C exhibited discharge capacities of 193.2, 175.6, and 173.7 mAh?g-1 at 0.1C, 0.5C, and 1.0C rates, respectively. Li3V2(PO4)3 impurities are formed and increased with increasing calcination temperature. When sintered at 650 °C Li3V2(PO4)3 is turn out to be the main phase. On the other hand, optimal duration time at high temperature could also inhibit the decomposition of LiVPO4F and decrease the formation of Li3V2(PO4)3 impurities, improving electrochemical performance. Optimal conditions were found at a residence time of 3 h when the precursor is sintered at 550 °C.