As dreamy as it might be to combine renewable energy sources with storage batteries, there's a problem: those batteries are expensive. It might take you years to recoup the costs. You'll be glad to hear, then, that Stanford scientists have a way to make those batteries more cost-effective. They've developed a liquid metal-based flow battery that can store electricity at a lower price, even on a large scale. A metal-producing mix of sodium and potassium serves as the negative side of the battery, providing nearly twice the maximum voltage of typical flow batteries (making them high-value) without having to resort to exotic chemicals or extreme temperatures.