There's pumped hydro, geothermal energy, and biofuel, in the future we'll likely see some wave power as well. The point isn't to have one technology for the entire grid but to have a diverse and distributed energy system.
For storage there are also many more options than just lithium ion batteries. We have sodium ion if you just want to swap battery for battery, but then there are also for example iron-air batteries that are projected to be dirt cheap, redox flow batteries, pressurized air, cryogenic energy, sand batteries for storing heat, hydrogen electrolysis, etc.
Not only will this make this a power grid that is less dependent on supply chains that are impacted by geopolitical conflicts, but it will also make it more resilient as the weather continues becoming more extreme.
That's the whole point of diversifying, use the sources that are available in the places where they are available.
The point is that the greenhouse gases that they emit have already been captured from the atmosphere, which makes them carbon neutral.
It uses a lot of the same type of production as lithium ion, it is already being produced by some of the largest battery manufacturers on the planet, and being sold on the market, and we have years of research to give us a good idea of how it will evolve.
Neither will fission plants. Even if we decided to start building out today, there are years before we actually see construction start, not to mention commissioning and eventually power production. We're probably talking about the 2040s at that point.
Some people, sure. But the person above wasn't talking about completely removing all fission, just that we should have started building nuclear plants twenty years ago because it's slow and comes with a massive up-front cost, and at this point we have other alternatives that are cheaper and faster to install. Nuclear fission plants are also a very centralized source of energy, so if there are issues in the future as a result of climate change (similar to what they've been experiencing in France) then you lose a lot of grid capacity all at once while trying to resolve it.
I think nuclear is a reliable source of power, I've been an advocate for it, but I don't believe it's the right solution at this point in time.