its just a simple idea I have always considered; loading electrical energy into physical potential energy by way of working against gravity. Maybe, instead, just run a big heavy chunk of metal up a notched pole? Then release it to spin a worm gear, to a large cog, then big generator as it slowly drops?
You'd still have the exact same issue with the amount of mass and/or height needed. Mass x height x 9.8m/s^2. For a kilowatt-hour of storage, mass x height needs to equal about 600,000. Gravity-based energy storage simply requires a lot of both for any worthwhile amount of energy.