I just answered a question about a lead crystal battery at solarpaneltalk.com from Jon (aka Beanyboy57), and thought it was worth sharing.

Question:  I have just recently heard about lead crystal batteries and read the 'data' presented on some websites which seems too good to be true. Claims of 7/800 cycles to 80% DOD. Does anyone have information on this type of battery or has used them for an extensive period?

Cheers
Jon

My Thoughts:  My first guess is that the battery is too expensive to manufacture and/or is not reliable. I remember a colleague of mine sharing a story about when they bought some battery technology from DuPont that would have revolutionized the industry. It was a fine hair like substance woven into a glass-matt that would allow the material to be built into clothing, for example. It worked great in the lab, but when they attempted to commercialize it they kept running into problems and had to abandon the idea. My second guess as to why it is not used is that crystals are a dense material and not conducive to electron passing.