November 20, 2017
Staff
As automakers are looking for alternatives to gasoline-fueled vehicle, hydrogen has always been an intriguing option, albeit very expensive for mainstream consumers.
UCLA researchers recognized this problem and designed a device that can use solar energy to inexpensively and efficiently create and store energy, enabling it to power electronic devices and to create hydrogen fuel for eco-friendly cars.
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Richard Kaner and Maher El-Kady in Kaner’s office. Kaner is holding a replica of a new energy storage and conversion device they developed. Photo Credit: Reed Hutchinson/UCLA.
One of the advantages of this device is that it is able to produce hydrogen using nickel, iron and cobalt, making it more affordable. Current methods use platinum and other precious metals, which are much more expensive and less abundant.
“Hydrogen is a great fuel for vehicles: It is the cleanest fuel known, it’s cheap and it puts no pollutants into the air — just water,” said Richard Kaner, the study’s senior author and a UCLA distinguished professor of chemistry and biochemistry, and of materials science and engineering. “And this could dramatically lower the cost of hydrogen cars.”
Kaner explains that the device solves two problems, making both electricity and fuel, enabling people to fuel their vehicles and run their electric devices.
It could also be part of a solution for large cities that need ways to store surplus electricity from their electrical grids.
“If you could convert electricity to hydrogen, you could store it indefinitely,” said Kaner, who also is a member of UCLA’s California NanoSystems Institute.
The UCLA device is different from traditional hydrogen fuel cells and supercapacitors, which have two electrodes — one positive and one negative. The device includes a third electrode that acts as both a supercapacitor, which stores energy, and as a device for splitting water into hydrogen and oxygen, a process called water electrolysis.
All three electrodes connect to a single solar cell that serves as the device’s power source, and the electrical energy harvested by the solar cell can be stored in one of two ways: electrochemically in the supercapacitor or chemically as hydrogen.
Another advantage of the device is that it produces hydrogen fuel through an environmentally friendly method. About 95 percent of production comes from converting fossil fuels into hydrogen. This process releases large quantities of carbon dioxide into the air, said Maher El-Kady, a UCLA postdoctoral researcher and a co-author of the research. Hydrogen energy can only be “green” if it is produced from renewable sources, El-Kady adds.
Kaner explains that the team’s design of combining a supercapacitor and the water-splitting technology into a single unit is akin to the first time a phone, web browser and camera were combined on a smartphone.
The UCLA team designed the electrodes at the nanoscale — ensuring the greatest surface area would be exposed to water, which increases the amount of hydrogen the device can produce and also stores more charge in the supercapacitor.
Currently the device was made to fit in the palm of your hand, the team has hopes that they can make a larger version for additional applications.
The technology is described in the journal Energy Storage Materials.
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