Form Energy has made a huge amount of marketing before they had proven anything and claimed to have a product very fast. They have not build a single large better ever. Maybe not exactly the best example.

Most of the non Li-Battery grid cell systems have not yet proven much. Many of the first generation of such system went bust. And many of the others have taken a long time and are still not deployed.

So far the successful grid battery companies are mostly repackaging other cells.