Remember the artificial leaf? Startup turns to making a flow battery instead

Two years ago the blogosphere hyped the promise of an “artificial leaf,” which is a sheet that uses a catalyst to harness the sun and split water into hydrogen and oxygen. The tech was based on research from MIT spin-out Sun Catalytix, and led by MIT Professor Daniel Nocera. But it turns out the startup won’t try to commercialize the artificial leaf any time soon, and according to a report in MIT Tech Review, it has now turned to using its research to make a flow battery instead.

Flow batteries are large liquid-filled tanks that are mostly used to store energy for the power grid. A flow battery’s electrolyte is stored in two tanks that are separate from the cell itself, and the flow battery generates electricity when the liquid electrolytes, which are mixed with energy-storing materials, flow through the two sides and react with the electrodes in each side of the cell.

The idea, which has been around for decades, is to create a lower-cost battery option than, say, lithium-ion batteries. Power companies like them because the batteries are rechargeable, and can be scaled up and down by adding more tanks. Companies working on this technology include EnerVault, ZBB Energy, Prudent Energy, RedFlow, Primus Power and Deeya Energy.

ZBB's flow battery
ZBB’s flow battery

Sun Catalytix tells MIT Tech Review that it hopes to have a prototype of its flow battery later this year, which it can test out with customers, and then raise more funds for additional product development at that point. The end product is supposed to be a 1 MW flow battery that can last four to six hours and fit inside a 40-foot shipping container.

It’s not uncommon for cleantech startups — or any startup — to pivot and shift their plan as they progress. The artificial leaf was in the research phase and the company realized that commercializing it would take many years and lots of money. Though, as this New Yorker article points out Nocera has a bit of a reputation for hyping his discoveries.

The problem, though, is that funds for commercializing next-gen energy technologies are very tight these days. And Sun Catalytix already received a $4 million grant from the Department of Energy’s ARPA-E program, as well as a $9.5 million Series B round led by India’s Tata and including existing investor Polaris Venture Partners.

Venture capitalists have started to move away from investing in energy tech, and government funds could be tight in 2013, too. Funding could be particularly difficult for an early stage technology, where there are clear competitors that are farther ahead.