There was quite an interesting article "Seasonal energy storage in aluminium for 100% solar heat and electricity supply" https://news.ycombinator.com/item?id=26

There was quite an interesting article "Seasonal energy storage in aluminium for 100% solar heat and electricity supply" https://news.ycombinator.com/item?id=26463249 https://news.ycombinator.com/item?id=26463249 I'm not sure how that got on - it was from 2021 - but something like that could be interesting. The stored product is aluminium metal and gets oxidised to hydrogen and aluminium hydroxide producing heat which can be used for heating and hydrogen that can be used in fuel cells or industrial processes.