Enhanced low voltage cycling stability of LiMn2O4 cathode by ZnO coating for lithium ion batteries

Aluminium doped spinel, LiAl0.04Mn1.96O4, was modified by melting impregnation using Zn(NO3)2. High-resolution transmission electron microscopy observations indicated that ZnO was coated on the surface of LiAl0.04Mn1.96O4 particles. Cycling tests between 2.60 and 4.35 V showed that the surface modification stabilizes the spinel structure and leads to a steady discharge capacity without Jahn–Teller distortion, which could be significant for LiMn2O4 based spinels in the 3 V region. It is found from high temperature aging experiments that the surface modification further suppresses manganese dissolution in the electrolyte and retains the structural stability upon cycling. The ZnO-coated LiAl0.04Mn1.96O4 spinel material prepared here shows a high capacity retention of about 95.9% per 100 cycles at 55 °C as compared to 82.2% for the unmodified one.