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

Abstract

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+delta 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 degrees 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 spinet 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 degrees C. The optimized sample, which was annealed at 700 degrees C, showed excellent thermal stability at 50 degrees 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.(C) 2017 Elsevier B.V. All rights reserved.