Caterpillar started a research project to reduce warranty claims on their starter batteries, which did not last long in the cold. Their team eventually realized

Caterpillar started a research project to reduce warranty claims on their starter batteries, which did not last long in the cold. Their team eventually realized they could replace the lead plates with a graphite foam. This gave their batteries the energy density of NiMH, for the cost of lead. They spun off the venture into Firefly Energy [1]. This company was tooling up for release, then the 2008 financial crisis hit. Eventually an Indian company bought the IP. I don't know if they are working towards commercialization or not... tl/dr: a better battery (probably) already exists, but is not fancy enough to get attention. http://fireflyenergy.com http://fireflyenergy.com