The new development in the search for fossil fuel alternatives comes from U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab.) The new process involves the production of hydrogen for fuel cells via an artificial photosynthesis process that splits water into hydrogen and oxygen. The new method is described as more efficient that conventional solar technology. This follows several years of researchers attempting to recreate photosynthesis under laboratory conditions in order to mimic the natural process to create fuel.
The achievement comes with new water-splitting technology described as a hybrid photoelectrochemical and voltaic (HPEV) cell. The cell converts sunlight and water into hydrogen fuel and electricity, both of which are usable forms of energy. With more established water-splitting technology the front surface of a device is used for solar fuels production and the back surface functions as an electrical outlet.
With the new HPEV device, the researchers succeeded in adding a additional electrical contact to the silicon component’s back surface. This created the HPEV device, where there are two contacts located in the back. This additional back outlet enables the current to be split into two, resulting in one part of the current being used for solar fuels generation, and the remainder is extracted as electrical power. This results in combined efficiency of 20.2 percent, three times better than conventional solar hydrogen cells.
Previous artificial photosynthesis devices could only utilize small quantities of the sunlight that comes into contact with them. Speaking with Engadegt, chief scientist Gideon Segev states: “It’s like always running a car in first gear. This is energy that you could harvest, but because silicon isn’t acting at its maximum power point, most of the excited electrons in the silicon have nowhere to go, so they lose their energy before they are utilized to do useful work.”
The new technology is described in the journal Nature Materials. The research paper is titled “Hybrid photoelectrochemical and photovoltaic cells for simultaneous production of chemical fuels and electrical power.”
