ε-MnO2@β-CDP cathode material enables highly stable aqueous zinc-ion battery

Mn-based cathodes have been widely explored for aqueous zinc-ion batteries (AZIBs) for their high theoretical capacity and low cost. However, Mn-based cathodes for AZIBs still exist unstable cyclic performance, which usually presents severe declination of the specific capacity during cycling. Here, beta-CDP-coated epsilon-MnO2 (MCD) has been synthesized by chemical precipitation and used as cathode materials for AZIBs in conjunction with Kaolin (KL)-based electrolyte. The synergistic effect of the beta-CDP coating and KL-based electrolyte are indicated to improve the electrochemical performance of epsilon-MnO2. A high specific capacity of 158 mAh g(-1) at 0.2 A g(-1) is obtained in the KL electrolyte after 100 cycles, with a capacity retention of 98.7 %. beta-CDP coated epsilon-MnO2 forms the layered structure, which creates additional space for efficient transportation of H+/Zn2+ ions during discharge/charge process. MCD exhibit high ion diffusion kinetics and ion conductivity in the KL-based electrolyte by GITT and EIS. The evolution of diffraction peaks and morphological changes during the discharging/charging process demonstrate the co-intercalation of H+/Zn2+ mechanism.