MnO₂synergized with N/S codoped graphene as a flexible cathode efficient electrocatalyst for advanced honeycomb-shaped stretchable aluminum-air batteries

Aluminum-air batteries possess high theoretical specific capacities and energy densities. However, the desired application performance in the field of flexible electronics is limited by the rigid battery structure and slow kinetics of the oxygen reduction reaction (ORR). To address these issues, flexible, stretchable, and customizable aluminum-air batteries with a reference to honeycomb shape are composed of multilayer single battery units to achieve large scalability and start-stop control. The single aluminum-air battery combines MnO2 with N/S codoped graphene to improve the electrocatalytic activity. Benefiting from an efficient electrocatalyst and reasonable structural design, the single aluminum-air battery exhibits excellent electrochemical characteristics under deformation conditions with a high specific capacity and energy density (1203.2 mAh g-1 Al and 1630.1 mWh g-1 Al). Furthermore, the obtained honeycomb-shaped stretchable aluminum-air batteries maintain a stable output voltage over the 2500% stretching. More interestingly, the stretchable honeycomb structure not only can solve the start-stop control problem but also has the potential to reduce the self-corrosion in disposable metal-air batteries. In addition, owing to the customizable shapes and sizes, the honeycomb-shaped stretchable aluminum-air batteries facilitate the integrated application of flexible batteries in wearables.