New Battery Uses Seawater and Freshwater to Produce Electricity


Stanford University researchers have designed a rechargeable battery that uses the contrast in salinity between freshwater and seawater to produce an electric current, an innovation they say could potentially be used wherever a river meets the ocean.

The battery contains two electrodes — one positive, one negative — immersed in a liquid that contains electrically charged sodium and chlorine ions.

The battery is initially filled with freshwater and given a small electric current, and then drained and replaced with salty seawater.

Because the seawater contains 60 to 100 times more ions than the freshwater, the voltage between the two electrodes increases, allowing users to gain more electricity than the amount used initially to charge the battery, according to a report published in the journal Nano Letters.

Researchers say that if such batteries were deployed in all of the planet’s estuaries, the technology could produce about two terawatts of electricity a year — roughly 13 percent of current global consumption.

Article appearing courtesy Yale Environment 360.

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Yale Environment 360 is an online magazine offering opinion, analysis, reporting and debate on global environmental issues. We feature original articles by scientists, journalists, environmentalists, academics, policy makers, and business people, as well as multimedia content and a daily digest of major environmental news. Yale Environment 360 is published by the Yale School of Forestry & Environmental Studies and Yale University. We are funded in part by the Gordon and Betty Moore Foundation and by the John D. and Catherine T. MacArthur Foundation. The opinions and views expressed in Yale Environment 360 are those of the authors and not of the Yale School of Forestry & Environmental Studies or of Yale University.

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