there are plenty of technologies that might be a threat to...

there are plenty of technologies that might be a threat to lithium 15 years in the future. Solid sodium is just one, and probably not the most likely. Personally, I think someone is going to work out a cheap production method for graphene (perhaps Rice University’s Flash Joule method is it?). And then a company like Skeleton who already has mass production plans, and a massive back order book for supercapacitors, will scale up to making supercapacitors in the bodywork of cars and building materials. Volvo has already built a bonnet that replaced the starter battery in a concept car. But that’s just speculation, and like solid sodium, not a realistic threat to PLS for a minimum of 15 years.