There is also this Czech failed battery startup "HE3DA". It went from revolutionary to evolutionary to "well, there is at least one parameter (robustness) that's better than lithium batteries" to "hmm the measurements don't quite match the specs". There were individual investors, big show for opening a factory (with capacity of 1.4GWH we were told; actual batteries sold in 2024: single digit MWhs). Now they fired almost everyone and can't pay their bills

https://www.e15.cz/byznys/prumysl-a-energetika/pravda-o-bate...