Al doped Mn2O3/2-Methylimidazole composites enhancing reaction kinetics for zinc ion batteries

Abstract

Manganese based material is a representative cathode materials for zinc ion batteries (ZIBs), which has the characteristics of high voltage and friendly environment. However, it has some difficulties in the study of capacity attenuation and manganese dissolution during the cycle. In this paper, 3%Al-Mn₂O₃ nanospheres were prepared by in-situ doping of Al ions by hydrothermal method, and then oxidized. Finally, 3%Al-Mn₂O₃ nanospheres were coated with 2-Methylimidazole(2-MI) to form 3%Al-Mn₂O₃/2-MI composite structure, which improved the cycle performance of the battery and effectively inhibited Mn escape during the reaction. The results show that the battery cycle stability and specific capacity are improved significantly, which is due to the effective Al doping, and the 2-MI coating effectively alleviates the dissolution of Mn during the cycle. At 0.1 A g^-1, the specific capacity of 3%Al -Mn₂O₃/2-MI cathode was still 134.2 mAh g^-1 after 100 cycles. And the cathode maintains 106.4 mAh g^-1 after 1000 cycles at 1.0 A·g^-1, has a better cycle stability. The co- insertion and extraction of H⁺ and Zn²⁺ in 3%Al-Mn₂O₃/2-MI cathode and the mechanism of the reaction process were studied by various methods. At the same time, 3%Al-Mn₂O₃/2-MI successfully assembled flexible quasi-solid ZIB, showing its development potential in applicable commodities.