Chinese scientists have made good use of waste while finding an innovative solution to a technical problem by transforming rusty stainless steel mesh into electrodes with outstanding electrochemical properties that make them ideal for potassium-ion batteries. As reported in the journal Angewandte Chemie, the rust is converted directly into a compact layer with a grid structure that can store potassium ions. A coating of reduced graphite oxide increases the conductivity and stability during charge/discharge cycles.