My guess, within 5 years, we'll see buried kinetic batteries for sale instead of chemical batteries. You'll have a big flywheel underground with magnetic bearings, and your solar panels will be pumping power into accelerating the flywheel until night. At night, the electric motor turns into a generator. It's spinning at thousands of RPM by this point and lasts until morning, at which point the whole thing starts again.
No chemicals, no plates to get crusted and wear out, and I bet it would be more efficient than batteries. You bury it so that if there's a failure, the ground absorbs the explosion.