Some diagrams would help those of us who are interested, but don't have a full background in electrochemistry. (I still haven't had a chance to look closely at the article you linked to, but it does seem to have some illustrations that could be edited into the video.)
Good to see progress on sodium batteries. Despite the weight and volume penalties when compared to lithium, it looks like sodium has large economic and environmental advantages, especially for large immobile installations, which could help even out the flow of power from sources like solar and wind. Maybe safety, too.