Improved Cycling Performance of Cation-Disordered Rock-Salt Li1.2Ti0.4Mn0.4O2 Cathode through Mo-Doping and Al2O3-Coating

Abstract

Cation-disordered rock-salt cathode material is a promising material for next-generation lithium-ion batteries due to their extra-high capacities. However, the drawbacks of large first-cycle irreversible capacity loss, severe capacity decay, and lower discharge voltage have undoubtedly hindered their application in commercial systems. In this study, cation doping (Mo4+) and atomic layer deposition (ALD) techniques were used to synthetically modify the Li1.2Ti0.4Mn0.4O2 (LTMO) material to improve the cycling stability. First, the optimal Mo-doped sample (Mo01) with the best electrochemical performance among the different doping amounts was selected for further study. Second, the selected sample was subsequently coated with an Al2O3 layer by the ALD technique to further optimize its electrochemical performance. Results show that the LTMMO/24Al2O3 sample, under optimal conditions, could obtain a specific discharge capacity of up to 228.4 mAh g−1 after 30 cycles, which is much higher than that of the unmodified LTMO cathode material. Our work has provided a new possible solution to address some of the capacity fading issues related to the cation-disordered rock-salt cathode materials.