Sodium Ion already does 5000+ cycles. Adding Vanadium is not a scalable material. It is very expensive. 400 cycles steady is not useful information because it needs to do much more. They didn't state a wh/kg density. This is probably not a viable research vector, but "big Vanadium" has proposed a rental model to make Vanadium more scarce for other applications. Flow batteries (a fuel cell with tanks of electrolytes) provides an ultra easy way of recycling/selling the vanadium for traditional uses. Battery rental that forces returning it could be viable.