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. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A capacity self-healing aqueous Zn/MnO2 battery was proposed using carboxyl-modified carbon nanotubes as the cathode substrate, achieving or recovering specific capacity by controllable electrodeposition of MnO2, significantly improving cycling performance.