Assault on the Traditional Battery?

Renewable energy sources (solar and wind power) can't deliver, when the sun doesn't shine and/or the wind doesn't blow. A claimed solution, is to store 'off peak' energy in giant conventional batteries. These, however, would utilise lots of expensive (and relatively rare) lithium; cadmium and nickel. There is another solution. Energy can simply be stored as heat, using relatively cheap and easily obtained materials (https://www.theguardian.com/environment/2024/apr/01/thermal-energy-storage-industry). These alternatives are being worked on by a variety of start-ups. For example, molten salt (sodium chloride) is good at holding heat, up to 500 degrees Centigrade. Installations, using this 'ingredient', can consequently be charged to high temperatures, when electricity from solar or wind power cheaply available. The stored heat energy, can subsequently be used to regenerate electricity. This would allow users (in housing or work places) to buy off-peak power but to have it available, when they actually need it. If widely-adopted, there would be no need for giant conventional batteries or back-up power stations, using fossil fuels or even nuclear energy. It's not just salt that has the ability to efficiently store heat energy. Other possibilities using air; bricks and even hand warmer gel, are currently being explored. There should be a bigger focus on this type of technology, rather than rushing to utilise older 'solutions'.