Artificial Leaves That Can Store Energy

Researchers have made an artificial leaf that can use sunlight to convert moisture in plants into hydrogen and oxygen which can be used as fuels

The technology developed by Dan Nocera of the Massachusetts Institute of Technology and colleagues could eventually power a house and bring electricity to the developing world with little more than a chip sunk into a bucket of water. The device could even store the energy for when the sun isn’t shining.

How It Works ?

The new technology copies the process of photosynthesis in which the sun’s energy liberates electrons in a leaf, which then split water to form hydrogen and oxygen, providing stored energy for the plant.

The leaves need two catalysts to make this reaction work, and similarly, so do the solar cells. Nocera’s breakthrough is in finding two affordable catalysts that can do the reaction.

The sunlight is captured with the same silicon material that makes up a typical solar panel, but instead of connecting it to wires that can charge a battery, the coated silicon with catalysts is submerged in water.

The hydrogen and oxygen could later be used in a fuel cell to generate electricity as they recombine to form water.

The device could match the efficiency of today’s solar panels, he added, meaning that an array of panels on a household roof would be enough to power the house.

But a key target for the team’s research is to provide energy to people in developing countries, especially India and rural China, he said. A key feature of his system in achieving this goal is that the device runs with whatever water is available; it need not be ultra-pure.

A remaining engineering challenge to take this from the lab to the rooftop is to figure out how to capture the oxygen and hydrogen and store them for later use. “That’s going to be some tricky engineering,” he said. It remains to be seen how expensive this aspect will be.

Today’s photovoltaic panels can store solar power in a battery, but “a lot of the cost of a solar panel is in the wiring, the packaging,” Nocera said. These expensive parts are eliminated with the artificial leaf. “In principle, that could be much cheaper.”