High capacity spinel@layered Li1.5MnTiO4+δ as thermally stable core-shell-driven cathode materials for lithium-ion batteries

The recently developed composite cathode can solve the disadvantages of single-component Lithium-ion batteries such as low capacity, low rate performance, and poor cycling stability. Spinel-layered Li1.5MnTiO4+δ composites synthesized by a solid-state reaction showed high capacity and excellent cycling stability at room temperature. However, this material showed very poor cycling stability at 50 °C. A novel approach was used to synthesize spinel@layered composites, with the thermally stable layered component located in the outer part, and the high-capacity spinel located in the inner part of the composite particles. The effects of annealing temperature on electrochemical performance of cathodes were studied at both room temperature and 50 °C. The optimized sample, which was annealed at 700 °C, showed excellent thermal stability at 50 °C with 92% capacity retention after 100 cycles at 1C, compared to the value of 87% shown by the solid-state sample. At room temperature, the optimized cathode exhibited enhanced capacities of 209 and 157 mAh g−1 at C/5 and 1C, respectively. Moreover, the optimized sample showed improved performance at different C-rates compare to the solid-state sample.