Metal from the trash heap may one day wind up inside your smartphone instead of the other way around thanks to a group of Chinese scientists. The scientists have figured out a way to turn rusted stainless steel mesh, a material often used for filters and screens in facilities such as wastewater treatment plants, into high-performing electrodes used in potassium-ion batteries. The new recycling method not only tackles the problem of excess steel-mesh waste, but also has the potential to make the potassium-ion battery a cheaper alternative to the more-commonly used lithium-ion battery.