Vanadium oxide seems to be the go-to guy in power storage right now. A new solid-oxide fuel cell -- developed at Harvard's School of Engineering and Applied Sciences -- that can also store energy like a battery, also uses the stuff. In the new cell, by adding a VOx layer it allows the SOFC to both generate and store power. Example applications would be situations where a lightweight power source is required, with the potential to provide reserve juice should the main
