Superior-Performance Aqueous Zinc Ion Battery Based on Structural Transformation of MnO₂ by Rare Earth Doping

Abstract

Doping with heteroatoms is being used as an effective way to change electronic structure of electrode materials for advanced storage systems. Herein, β-MnO2 and rare earth (cerium) doped MnO2 cathode materials have been successfully prepared for aqueous zinc ion batteries. Cerium doping induced structural transformation of MnO2 from β- to α-phase, along with the evident improvement of conductivity, stability, and reversibility. Compared to the undoped β-MnO2, the doping cathode possessed excellent cycling stability at a high rate of 5 C and higher rate capability. Cyclic voltammetry curves, electrochemical impedance spectroscopy, galvanostatic intermittent titration technique, scanning electron microscopy, and transmission electron microscopy measurements demonstrated that cerium doping caused fast Zn2+ diffusion and excellent electrochemical stability.