Photovoltaic solar cells generate electricity that must be used immediately or stored, but an artificial leaf could store solar energy in a different manner, chemically.
Researchers at Massachusetts Institute of Technology [MIT] have recently unveiled an artificial leaf prototype that does indeed generate electricity when exposed to sunlight, but when placed in water, generates hydrogen and oxygen gas by electrolysis.
Photovoltaic energy from the cell was insufficient to start the reaction, so the solution was either link more than one cell, or to apply the catalyst. The artificial leaf isn’t just a photovoltaic cell, but combines this with a catalyst coating on both sides of the cell. By combining the electrical and chemical properties of the two systems, hydrogen and oxygen are efficiently separated from each other. The resulting gases can be stored and fed back into a fuel cell to generate electricity on demand.
MIT’s research into increasing the efficiency of an artificial leaf is important, especially considering solar energy, and other renewables like wind, intermittence. When it’s cloudy, solar power is reduced, and when it’s night, solar power fails completely, but being able to store this energy chemically for use later makes it even more useful. Battery technology is extremely expensive, but efficient. If storing solar energy as hydrogen gas can be made more efficient, then it could prove to be cheaper.