Yttrium doping improves stability of manganese dioxide cathode for aqueous zinc ion batteries

Abstract

Manganese-based oxides are a promising cathode material for aqueous zinc ion batteries. However, structural change and irreversible dissolution of manganese in manganese-based oxides during charging and discharging lead to poor cycling stability, which hinders their large-scale application. Elemental doping is an effective way to regulate the bonding strength and crystal structure of the material. In this paper, YMO materials with nanorod-like structures have been obtained by a hydrothermal method. Y-element doping enhances the stability of the material and improves the electronic and ionic conductivity of the material. The YMO material exhibits excellent electrochemical performance as a cathode material for aqueous zinc ion batteries. The electrode exhibits a high reversible discharge specific capacity of 409.3 mAh g−1 at a current density of 0.1 A g−1, and the electrode capacity hardly decays after 100 charge/discharge cycles, meanwhile, the YMO electrode shows good initial cycling stability even at different charge/discharge current densities. In addition, the YMO electrodes showed long-term cycling stability, with a capacity retention rate of 95.1% after 2000 cycles at a current density of 1 A g−1. The excellent cycling stability of the electrode is mainly due to the improved structural stability of YMO, which is related to the stronger YO bonds acting as anchors in the lattice structure of MnO2. Meanwhile, the strong interaction between doped Y3+ and O2− promotes the storage of H+. Structurally stable electrode materials obtained by optimizing doping elements to modulate bonding energy is an effective way to improve the stability of manganese-based materials.