Establishing non-Newtonian flow state K metal electrodes for flexible batteries

Potassium metals are promising anodes owing to their wide distribution and low redox potential. Nevertheless, their application in flexible devices is impeded by their poor mechanical properties. Herein, we fabricate a moldable and processable non-Newtonian flow state K metal anode (NK) by encapsulating molten K into Super P powder in a short time. The NK slurry can be arbitrarily designed in various shapes and precise sizes with excellent viscosity, and stabilize K metal anodes at near room temperature (around 100 °C). Further, with the support of a stainless steel mesh carrier, the mechanical stability and corrosion resistance of the electrodes tend to be more honorable. Remarkably, the NK metal based on stainless steel mesh (NK@SS) exhibits excellent cycling performance at high current density. Paired with a Prussian blue (PPB) cathode, the NK@SS anode shows better electrochemical performance and extended lifetime than bare K. The pouch cell based on the NK@SS anode can function well at various bending states without obvious capacity attenuation. These results may lay the foundation for the design of advanced materials.