These novel batteries technologies could be the future of energy storage Over the past decade, prices for solar panels and wind farms have reached all-time lows. However, the price for lithium ion batteries, the leading energy storage technology, has remained too high. So researchers are exploring other alternatives, including flow batteries, thermal batteries, and gravity-based systems. If they can crack the code for long-duration energy storage, renewables like wind and solar will finally be able to compete with fossil fuels.