Improvement of Cathode Properties by Lithium Excess in Disordered Rocksalt Li 2+2 x Mn 1− x Ti 1− x O 4

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 Li2+2xMn1-xTi1-xO4 compositions (0 ≤ x ≤ 0.3) with Li excess to further improve the cathode properties of Li2MnTiO4. The rechargeable capacity of the synthesized Li2.4Mn0.8Ti0.8O4 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 Li2.4Mn0.8Ti0.8O4 was ca. 190 mAh g-1 after the 15th cycle, and its capacity retention was 82%.