High-Performance, Stable, and Flexible Direct Methanol Fuel Cell Based on a Pre-swelling Kalium Polyacrylate Gel Electrolyte and Single-Atom Cathode Catalyst

Flexible devices are widely used in wearable devices and portable devices, so it is necessary to develop flexible batteries as power sources. On the other hand, due to their high efficiency and low pollution, fuel cells are friendly and safe for the environment and are the trend of future energy development. In this article, we report a strategy to achieve high-performance, stable, and flexible direct methanol fuel cells (DMFCs) based on the quasi-solid kalium polyacrylate hydrogel electrolyte and Fe single-atom cathode catalyst. The flexible DMFC delivers a maximum power density of 8.86 mW cm–2 at 30 °C, with excellent stability and robust performance under different bending degrees. Moreover, with the pre-swollen electrolyte, the flexible DMFC can continue to discharge for 54 h without adding fuel. It provides a promising power source for flexible wearable equipment and medical testing equipment. In short, the flexible DMFC that fixes the electrolyte in the gel provides ideas for the diversified design of flexible devices.