Constructing accommodational space in MnO2 cathode for Mn2+ transport and electrodeposition for aqueous zinc-ion batteries

MnO2 is the most desirable cathode material for aqueous zinc ion batteries; however, its electrochemical performance is still limited by the problem of structural collapse that inevitably occurs due to the dissolution-deposition mechanism. Here, the structure-induced problems are mitigated by designing physical accommodation space by dissolving the Nano-ZnO template for the MnO2 cathode. By having facilitated more open surfaces for the electrode reaction and provided channels for the diffusion of Mn2+ and Zn2+, the physical accommodational space significantly improves the electrochemical performance of the cathode. As expected, the rate and cycling performance of the pore cathode (540.6 mAh g−1 at 0.2 A g−1, 289.5 mAh g−1 at 1.0 A g−1) is superior to that of the normal δ-MnO2 cathode (406.2 mAh g−1 at 0.2 A g−1, 243.1 mAh g−1 at 1 A g−1), at the same time, the discharge specific capacity is 230% of that of the Regular electrode after 500 cycles at 1.0 A g−1 current density. This simple method of making improvements on made cathodes yields unexpected results, which alleviated the capacity decay of the normal electrode in the first 100 cycles. This study will elucidate the development of high stability cells by constructing better MnO2 electrodes by an electrode de-template method for zinc ion batteries.