Firefly Energy, a startup that hoped to breathe life into lead acid batteries, has been squished.

The company, which spun out of construction giant Caterpillar, has filed for Chapter 7 bankruptcy, according to the Peoria Journal Star. The City of Peoria, Illinois may pursue claims to get back $6 million in loans.

The company developed a way to coat the battery membrane, a fan-like lead lattice, with graphite foam. The change resulted, in theory, in a more efficient battery that could extract more electricity from the electrolyte and release more electricity per charge. Firefly also said its Oasis battery would have a longer lifetime. 

The battery was designed for long-haul trucks. Truckers typically run their diesel rigs all night, mostly to keep the air conditioning or heating going in their sleeping units. Want to watch reruns of BJ and the Bear? Better keep the engine going. In 2008, California introduced regulations that only allowed truckers to run their rigs in idle for five minutes every hour. Firefly had hoped to sell its batteries to truckers to run their cabins once all-night idling went away. (Here's an early story on them.)

Despite raising several rounds of funds, Firefly needed more money and government loans.

Interestingly, it is the second company specialized in batteries and battery components to go under. Last year, Imara, which had developed a novel cathode for lithium ion batteries, closed its doors.

One complaint in the battery community has been that the Department of Energy has given the bulk of its grants to established companies, like Compact Power, a joint venture run by South Korea's LG Chem. Startups like Imara, Boston Power and Firefly didn't get the requested grants and loans. While that may be true, A123 Systems, which was a struggling startup just 18 months ago, has received DOE grants. In addition, the battery industry tends to be dominated by large manufacturers. In January, the DOE issued big-rig grants to giants like Cummins and Ford. The DOE picks winners with its grants and loans, yes, but without the financial support, all of these projects would be doomed.

Quallion, which makes a battery that provides a similar function to the ones created by Firefly, has been seeking millions in DOE loans, too.