A bimetallic-activated MnO2 self-assembly electrode with a dual heterojunction structure for high-performance rechargeable zinc-air batteries

A major challenge in developing zinc-air batteries (ZABs) is to exploit suitable cathodes efficiently accelerate the key electrocatalytic processes involved. Herein, a bifunctional oxygen catalytic self-supported MnO2-based electrode designed that displays superior reduction and evolution reaction performance over noble metal electrodes with total overpotential of 0.69 V. In addition, as-synthesized NiCo2O4@MnO2/carbon nanotube (CNT)-Ni foam can be directly used as an without externally adding carbon or binder shows reasonable battery high peak power density 226 mW cm-2 long-term charge-discharge cycling lifetime (5 mA for 160 h). As expected, rapid intrinsic kinetics NiCo2O4@MnO2/CNTs-Ni originates from unique three-dimensional hierarchical structure, which effectively promotes mass transfer. Furthermore, CNTs combined Ni form “meridian” conductive structure enables electron conduction. Finally, abundant Mn3+ active sites activated by bimetallic ions shorten distance between reactant reduce surface activity MnO2 O, OH, OOH species. This work not only offers high-performance ZABs but also opens new insights into activation Mn-based electrodes.