Ya! And there is a lot of research and investment into them. The problem is they lose capacity over time from being powered and drained (think phone batteries and other lithium batteries). From what I know hydro batteries are actually really big with power companies. Basically pumping a bunch of water uphill when you have excess power, then using the reservoir like a hydro plant when you need power. They are really inefficient, but work surprisingly well at storing a lot of power