Enhanced cycling stability of LiMn2O4 by surface modification with melting impregnation method

The surface of as-prepared LiMn2O4 was modified with Al2O3 by a melting impregnation method. X-ray diffraction, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies indicated that Al2O3 nano-particles are distributed around the spinel. X ray absorption fine structure analysis (XAFS) further demonstrated that Al atoms were also doped to the surface of LiMn2O4 particles. The nano-Al2O3 particle coating improves the capacity retention of spinel LiMn2O4 efficiently at both room temperature and 55 deg. C. The mechanism of improvement for surface modified LiMn2O4 can be attributed to the inhibition of a surface Jahn-Teller distortion and the decrease of manganese dissolution, leading to good electric contact among particles