改进液相共沉淀法制备LiFePO_4和掺杂Cu~(2+)的研究

依据电化学原理,提出改进液相共沉淀制备LiFePO_4前驱体的方法.以价廉稳定的Fe~(3+)化合物作铁源,在共沉淀的过程中不需要惰性气体保护,然后在较低温度下(550 ℃)于氮气气氛中焙烧得到橄榄石型LiFePO_4.研究烧结温度对产物性能的影响,550 ℃下烧结得到了电化学性能优良的纯相LiFePO_4.通过改进共沉淀制备掺铜的LiFePO_4正极材料,它具有153.10 mAh·g~(-1)的初始容量(0.1 C),比未掺杂的LiFePO_4提高了11%.经过30次循环后,容量降到140mAh·g~(-1).

Study of Cathode Material LiFePO_4 and Cu~(2+)-Doped by Improved Liquid Coprecipitation Method

This paper studied the precursor of LiFePO_4 cathode materials synthesized by improved liquid coprecipitation method on the basis of electrochemical theory. Fe~(3+) compound was used as iron source for its low cost and good stability, and the process of co-precipitation was not necessary under inert gas atmosphere. Then, an order olivine structure LiFePO_4 was synthesized by roasting at lower temperature (550 ℃) in nitrogen atmosphere and the pure LiFePO_4 with good electro-chemical performance could be synthesized after the study of influence of roasting temperature on the properties of products. The testing results show that an initial discharge capacity of 153.10 mAh·g~(-1) at 0.1 C, was achieved for the LiFePO_4 material doped with Cu~(2+) prepared by improved liquid co-precipitation method, which is 11% higher than that without doping. What's more, the capacity decreased to 140 mAh·g~(-1) after circulations of 30 times.