What the PbC does is have a carbon electrode on the negative plate, which prevents most of the sulfation problems. The positive plate experiences much less.
This is exciting because hybrid vehicles and other power applications demand many more cycles than traditional ICE auto. Previously this niche was only available to expensive and explosive Li-ion batteries. Now cheaper and safer lead-carbon batteries could be used (though they contain less energy).
Axion Power is a development stage company that holds the patent for a pure negative electrode PbC. Other competitor batteries pale by an order of magnitude to the number of cycles it can take.
It currently has the train company Norfolk Southern developing an all-electric train using Axion's batteries.
http://cleantechnica.com/2013/10/26/new-life-green-weenie-el...
Axion also has auto companies, energy storage companies, and trucking companies developing apps using the PbC.
http://www.marketwatch.com/story/axion-power-announces-order... http://www.rigzone.com/news/oil_gas/a/129019/Locomotive_Tech...
The reason the stock price is at 16 cents right now is because Axion has spent a decade developing the technology and is only beginning to see revenue. It has to raise money to continue operations. But the time is close.
A risky but potential very rewarding investment. Each potential market for their battery number in the billions.