Grid-scale lithium ion batteries are our current go-to chemical energy storage solution, but they present their own challenges in safety, sustainability, cost, and longevity. However, the competition is … heating up. New forms of thermal energy storage systems built using abundant, cheap materials are on the rise. One company is aiming to sidestep the complications that come with chemical batteries…with a brick battery. And another company’s weapon of choice is a crushed volcanic rock battery. Talk about going back to basics to store massive amounts of energy. But is simple really best?