Optimised current cells, next-gen cells, and next-next-gen cells are all projected for similar price per kWh (one that makes any storage approach more than "buy us time to spin up a burner" impossible). For the record, that's now what I've heard from:

private market analysts, government strategists, and scientists.

As always, please show me a credible plan that says otherwise. I would be extremely happy to be proven wrong.

My sources have been two large private investment firms, a government agency, and a university research group. None thought that 5% of my countries' GDP - an amount easily enough to fund a permanent comparable nuclear output with the second most inefficient funding structure ever devised - could, at any point in the conceivable future, cover the energy shortfall this week in batteries, even the scientists who are typically financially optimistic. This week has been a 99th-percentile week at worst, more likely 95th.