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Graphene-Coated Solar Panels Could Someday Convert Raindrops Into Electricity

ByAllison EckNOVA NextNOVA Next

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Graphene is quickly becoming science’s new best friend.

At just one atom thick, this sheet of carbon could both simplify and revolutionize technology—from tissue engineering to

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drug delivery . And when combined with salt water, it has unexpected potential.

Back in 2014, researchers in China discovered that exposing a graphene surface to salt water (in that particular case, copper chloride) generates an electric potential. Now, a team of scientists led by Qunwei Tang of China’s Ocean University has found that this effect could render solar panels more effective—even in the absence of sunlight.

solar-panel-rain_2048x1152
No sun doesn't mean no use.

Here’s Olivia Goldhill, writing for Quartz:

Here’s how their planned solar panel would work. Raindrops would form a layer of positive ions, which are found in the salt of rainwater. Meanwhile, graphene is rich with delocalized electrons—which are free to move around. This forms a double layer—where positive and negative charges are separated—creating an electric potential between them. The separation in the double layer creates a voltage, just like in a battery.

Unfortunately, the test panel—which was already painted with water far saltier than typical rainwater—produced a small percentage of an average AA battery voltage. Another obstacle facing the team is the fact that graphene cannot yet be mass-produced (though, that could change ). Still, if the team can make improvements on their prototype, solar panels could someday become a lot more practical and widespread.