University of Sydney researchers have found a solution for one of the biggest stumbling blocks preventing zinc-air batteries from overtaking conventional lithium-ion batteries as the power source of choice in electronic devices.Zinc-air batteries are batteries powered by zinc metal and oxygen from the air. Due to the global abundance of zinc metal, these batteries are much cheaper to produce than lithium-ion batteries, and they can also store more energy (theoretically five times more than that of lithium-ion batteries), are much safer, and are more environmentally friendly.