Reinforcing cycling stability and rate capability of LiNi0.5Mn1.5O4 cathode by dual-modification of coating and doping of a fast-ion conductor

Abstract

A simple solid state method was utilized to synthesize excellent spinel Li2SiO3-modified LiNi0.5Mn1.5O4 cathodes. Dual-modification of coating and doping of fast-ion conductor Li2SiO3 leads to stable crystal structure and additional three-dimensional (3-D) channels for Li+-ion diffusion, and protects the electrode surface from electrolyte attack. The Li2SiO3-modified material possesses coexistence of ordered P4332 and disordered Fd-3m phases. As a result of improved structure, morphology and conductivity, the Li2SiO3-modified LiNi0.5Mn1.5O4 shows more superior cyclic performance, rate capability and high temperature stability than the pristine: capacity retention of 95.17% at 0.1 C after 100 cycles vs. that of 79.23%; rate capability of 130–89.1 mAh g−1 at 0.1–10 C vs. that of 120–57.6 mAh g−1; and high temperature capacity retention of 99.42% at 0.1 C vs. that of 79.59%. Our study provides a facile approach to stabilize crystal structure, optimize morphology and conductivity, and thus enhance electrochemical performance of LiNi0.5Mn1.5O4-based materials.