表面包覆尖晶石型LiMn_2O_4电化学性能研究

Electrochemical properties of coated spinel LiMn_2O_4

介绍了用软化学法制备表面包覆有LiCoxMn2-xO4的尖晶石型LiMn2O4,以及用循环伏安、恒流充放电和电位衰减方法试验了包覆前后样品的电化学性质。试验结果表明:包覆样品比未包覆的初始容量低;经50次循环后,未包覆样品的容降为56.2％,而表面包覆样品的容降则为33.5％,而且,包覆样品在电解液中的化学稳定性明显比未包覆样品高。结果还表明:表面层LiCoxMn2-xO4的存在减少了LiMn2O4在电解液中的溶解,提高了尖晶石型LiMn2O4的循环稳定性。

LiCoxMn2-xO4 - coated spinel LiMn2O4 was prepared by soft chemistry process, then the LiCoxMn2-xO4 - coated spinel LiMn2O4 and the uncoated spinel LiMn2O4 were characterized by methods of cyclic voltammetry, constant current charge - discharge and potential decay. Ther results showed that the initial capacity of LiCoxMn2-xO4 -coated spinel LiMn2O4 was lower than that of uncoated spinel LiMn2O4 After 50 cycles, the capacity loss of uncoated spinel LiMn2O4 was 56. 2% of initial, while that of LiCoxMn2-xO4 -coated spinel LiMn2O4 was 33. 5%, and LiCoxMn2-xO4 - coated spinel LiMn2O4 had better chemical stability than uncoated spinel LiMn2O4. Better cyclic stability of LiCoxMn2-xO4- coated spinel LiMn2O4 may be attributed to the surface layer LiCoxMn2-xO4, which reduces the LiMn2O4 dissolution into electrolyte.