The cells created by De Jonghe, Visco, Liu, and Armand are continuing to evolve. To date, more than 15 disulfide polymers have been evaluated, with hundreds of useful compounds yet to be examined. De Jonghe notes that different compounds have different electrochemical characteristics, allowing various cell types to be made for a range of applications. Some compounds are more suitable for ambient temperature operation. As researchers explore commercial opportunities and continue research and development efforts, their quest for a workable sodium battery has not been forgotten.
Sodium is even cheaper and more plentiful than lithium.
In a battery to power a car, sodium might be preferable. The new cathodes will work with sodium if we can find a polymer electrolyte separator which won't react with sodium. That, however, is a whole new problem.