Batteries are constantly improving, but people continue to demand more from their devices, so it's hard to tell. Some researchers are working on new energy storage devices that would leave current batteries in the dust and would be impossible to ignore as an option in vehicles and on the grid.

However, many industry analysts say the technology isn't the limiting reagent. On the grid, regulations are making it hard for batteries to catch on and in vehicles, low fossil fuel prices are moving the goal posts for energy storage.