Virtually ( for that, read effectively all) Lithium ion cell production is in China. Period. You want lithium, you are buying from them. They are the innovators in both design and manufacture. Brands such as CALB and Winston have been around a fair while , there have been incremental advances on them. While you can buy batteries which are assembled here, that's as far as it goes. The actual collection of parts used, ie, quality and size of BMS, internal connection methods and mounting of components and how they are assembled goes a long way towards determining ultimate longevity.
As to nuclear power, yes, I think it would be a cheap form of baseload. Unfortunately, words like Chernobyl and Fukushima tend to get in the way.