Li2O-B2O3-Li2SO4 modified LiNi1/3Co1/3Mn1/3O2 cathode material for enhanced electrochemical performance

A poor performance of the ternary cathode material, LiNi1/3Co1/3Mn1/3O2, at rate capability and low temperature, limits its further application, in electronic markets. Some of the previous research works report that surface modification of cathode materials can enhance their cycle stability. In the current work, (42.5-x) Li2O: 57.5B2O3: xLi2SO4 modified LiNi1/3Co1/3Mn1/3O2 cathode materials are prepared via the solution method followed by heat-treatment at 500 °C. The lithium fast ion conductors (42.5-x) Li2O: 57.5B2O3: xLi2SO4 provide a stable surface protection for LiNi1/3Co1/3Mn1/3O2. The results indicate that (42.5-x) Li2O: 57.5B2O3: xLi2SO4 modified LiNi1/3Co1/3Mn1/3O2 exhibits enhanced electrochemical performance at high rates and low temperatures. (42.5-x) Li2O: 57.5B2O3: xLi2SO4 (x = 10) modified LiNi1/3Co1/3Mn1/3O2 samples increase the discharge capacity retention of LiNi1/3Co1/3Mn1/3O2 from 33.4% to 85.3% at the rate of 1C and from 48.6% to 70.0% at −20 °C. The high resolution transmission electron microscopy and scanning electron microscopy confirm the existence of a thin Li2O-B2O3-Li2SO4 coating layer (about 10 nm) on the original structure of LiNi1/3Co1/3Mn1/3O2. The cyclic voltammetry and electrochemical impedance spectroscopy test results demonstrate that the presence of LBO-S coating reduces the interfacial resistance towards lithium ion migration.