Battery researchers go with the flow for renewable energy storage

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Researchers from Harvard's School of Engineering and Applied Science have demonstrated a type of battery which could transform the way in which electricity is stored on the grid. This, they claim, could make power from renewable energy sources such as wind and solar more economical and reliable.

The metal free flow battery draws on the electrochemistry of small organic molecules called quinones; similar to the molecules that store energy in plants and animals. Quinones are abundant in crude oil, as well as in green plants. The molecule used in the first quinone-based flow battery is almost identical to one found in rhubarb. Flow batteries store energy in chemical fluids contained in external tanks, instead of within the battery container itself, and the amount of energy that can be stored is limited only by the size of the tanks. Until now, says the team, flow batteries have relied on chemicals that are expensive or difficult to maintain, as well as precious metal electrocatalysts. The Harvard flow battery uses chemicals that are significantly less expensive, and no precious metals. Team leader Professor Michael Aziz, pictured, said: "So far, we've seen no sign of degradation after more than 100 cycles, but commercial applications require thousands of cycles." He also expects to achieve significant improvements in the underlying chemistry of the battery system. "The chemistry we have right now might be the best that's out there for stationary storage and quite possibly cheap enough to make it in the marketplace. But we have ideas that could lead to huge improvements."