以二甲亚砜水溶液为反应介质低温合成纳米级磷酸亚铁锂

摘要

采用二甲亚砜水溶液为反应介质,在常压和108℃条件下,经短时间的液相反应直接制备出橄榄石结构的纳米级LiFePO4.IR分析表明,液相法直接制得的LiFePO4晶体结构中含有少量的Fe3＋.将液相直接制备的样品与少量葡萄糖混合后在600℃下焙烧3 h得到类球形的LiFePO4/C材料.电化学测试结果表明,这种纳米级LiFePO4/C材料在0.2 C倍率下放电容量达到157.2 mAh/g,并且具有较好的放电平台.5 C和10 C放电容量仍能达到126.1和103.4 mAh/g,且循环200次后容量没有明显衰减,表现出优异的倍率放电特性和循环性能.%Nanometer-sized LiFePO4 with a well-developed olivine-type structure was synthesized in the dimethyl sulfoxide（DMSO）/H2O system under ambient pressure and 108 ℃.From IR analysis,less amount of Fe3＋ ions were proved to exist in the composite by solution-phased method.The sphere-like LiFePO4/C nanocomposite was obtained by sintering the mixture of nanometer-sized LiFePO4 and glucose at 600 ℃ under inert atmosphere for 3 h.The electrochemical tests showed the specific capacity of LiFePO4/C nano-composites at discharge rates of 0.2 C was 157.2 mAh/g.A capacity of 126.1 mAh/g at 5 C and 103.4 mAh/g at 10 C was even achievable,with no significant capacity fading after 200 cycles.