This video is about a year old, but still interesting and now available on Netflix.
Search for the Super Battery
The Aquion company went through bankruptcy, now owned by a join American / Chinese partnership (which my guess says is about 90/10% in favor of the Chinese). Aquion was the first to create a product focused on using the absolute cheapest and most abundant materials; others are also investigating that kind of battery.
What I found most interesting is that a battery can be made using almost any combination of elements if they are at all reactive. The "beach battery/stranded on a desert island" at the beginning is a hoot!