Yawn. I've been following this concept, and a wide array of very talented scientists working on it, for years now.

Any of the below projects, should they ever see the light of day (you'd think out of this many, at least one will make it eventually), stands a good chance of being quite superior for this application in just about every way:

http://www.eosenergystorage.com/technology-and-products/

http://www.ambri.com/technology/

http://www.ultrabattery.com/technology/

http://www.axionpower.com/Technology

http://www.lightsail.com/

http://www.drexel.edu/now/archive/2014/November/MXene-clay/