To add to my initial thoughts on gravity storage, the formula for potential energy in a gravity battery is basically mass x height x 9.8 m/s^2 . The sheer amount of weight and distance necessary to store a reasonably useful amount of energy makes for very large scale engineering projects.

The typical cell phone battery holds about 4000 mAh in a 3.7V battery, which translates to about 14.8 Wh, or 53.3 kJ. In order to get the equivalent storage in a gravity systems with a 1000 kg (1 tonne) weight, you'd need to raise it about 5.4 meters, with 100% efficiency.

A Tesla battery capacity is 75 kWh for some of the long range models, which translates to 270 MJ. To store that amount of energy you'd need to raise a 1-tonne weight about 27.6 km, about 3 times the altitude of Mt Everest and more than double the typical cruising altitude of commercial passenger jets.

So the most practical real-world projects they're pursuing tend to use weights of around 20-25 tonnes in abandoned mine shafts as deep as 3km, and can recover the energy at something like 80% efficiency. Each weight can therefore store something like 735 MJ or 204 kWh (aka 3 Tesla batteries). But obviously these types of projects are very expensive and complex, and require enormous scale to be cost effective.