Improvement of Cathode Properties by Lithium Excess in Disordered Rocksalt Li_2+2xMn_1−xTi_1−xO₄

Abstract

Although Li₂MnTiO₄ has a large theoretical capacity (295 mAh g⁻¹), the cathode utilization is limited due to the mixed cation occupation in the disordered rocksalt structure. In this study, we have attempted to prepare single-phase Li_2+2xMn_1−xTi_1−xO₄ compositions (0 ≤ x ≤ 0.3) with Li excess to further improve the cathode properties of Li₂MnTiO₄. The rechargeable capacity of the synthesized Li_2.4Mn_0.8Ti_0.8O₄ composition was above 220 mAh g⁻¹, which is larger than those of other disordered Li₂MTiO₄ (M = Ni, Co, Mn and Fe) series. Moreover, the discharge capacity of Li_2.4Mn_0.8Ti_0.8O₄ was ca. 190 mAh g⁻¹ after the 15th cycle, and its capacity retention was 82%.