High-Capacity Aqueous Zn/MnO2 Batteries: A Clue of K Ion Preintercalation

Layered δ-MnO2 materials are thought to be ideal cathode materials for zinc ion storage due to their open working channels. However, the structural collapse during long cycling largely affects the performance of the device. It is an efficient strategy through the preintercalation of cations to modulate the electrode structure. In this work, the K+ ion is introduced into the δ-MnO2 interlayer using a one-step solvothermal route. Using the as-prepared samples as the cathode, the assembled cells deliver a capacity of 389 mA h/g at 0.2 A/g and a capacity retention of 95% after 1000 charge/discharge cycles. It demonstrates their important application prospects in future portable electronics fields.