A self-healing neutral aqueous rechargeable Zn/MnO₂ battery based on modified carbon nanotubes substrate cathode

Rechargeable aqueous Zn/MnO₂ batteries show great potential for grid-scale storage due to their low cost, high safety, and energy density, yet suffer from continuous capacity decay during operation. Therefore, this work proposes a capacity self-healing aqueous Zn/MnO₂ (Zn/cCNTs-MnO₂) battery using carboxyl-modified carbon nanotubes (cCNTs) as the cathode substrate, ZnSO₄ + MnSO₄ mixed aqueous solution as the electrolyte, and Zn foil as the anode. Based on the controllable electrodeposition reaction of MnO₂, the specific capacity of Zn/cCNTs-MnO₂ batteries can be achieved or recovered by operating several cycles under a low current density (0.1 mA cm^-2). Then, the batteries can stably perform under a high current density (1 mA cm^-2). By repeating the above steps, a capacity self-healing usage scheme was established, which can significantly improve the cycling performance of Zn/cCNTs-MnO₂ batteries. Moreover, the results of the proposed Zn/cCNTs-MnO₂ batteries verify the MnO₂ electrodeposition mechanism and introduce a novel method for the development of durable aqueous rechargeable Zn/MnO₂ batteries.