球形尖晶石LiMn_2O_4的制备及其改性

Spherical Spinel LiMn_2O_4 Preparation and Its Electrochemical Performance Improvement

通过制备球形高密度前驱体MnCO3,并对其预烧,得到球形高密度、高活性的尖晶石LiMn2O4,密度>1.8g·cm-3,纯相初始容量达125mAh·g-1.通过对前驱体MnCO3的体相掺杂和对预烧产品Mn2O3的表面包覆,制备得到体相掺杂和表相掺杂的尖晶石锂锰氧,其循环及高温性能得到明显改善.与体相掺杂相比,表相掺杂能更有效地抑制容量衰减,常温100个循环仍有109mAh·g-1,容量保持率为92.4％;高温55℃,50个循环仍有95mAh·g-1,容量保持率为82.6％.

The high-density spherical precursor MnCO3 was prepared by controlling the reaction conditions. Furthermore, the spinel LiMn2O4 Was obtained from the precursor, which was obtained by pre-heat treatment. The product spinel LiMn2O4 has high density of more than 1.8g(.)cm(-3) and high electrochemical activity with initial discharge capacity of 125mAh(.)g(-1). The body-doped spinel LiMnO can be obtained by preparing doped precursor MnCO3 and the surface-doped spinel LiMnO can be obtained by coating Mn2O3. Both of the methods can improve the cycling performance and high temperature performance obviously with initial discharge capacity little lowering. Compared with body-doping, surface-doping can restrain the capacity fading more effectively. It still preserves 109mAh/g after 100 cycles at room temperature, the capacity retention is 92.4%. At high temperature of 55degreesC, it has 95mAh/g after 50 cycles and capacity retention of 82.6%.