Sustainable Skies: Three-in-One Device Stores Energy, Makes Hydrogen
UCLA researchers Richard Kaner and Maher El-Kady, “Have designed a device that can use solar energy to inexpensively and efficiently create and store energy, which could be used to power electronic devices, and to create hydrogen fuel for eco-friendly cars.” Kaner and El-Kady have devised many low-budget approaches to capturing and exploiting energy, such as their method of “burning” supercapacitors on a personal computer DVD. Their newest accomplishment, according to Kaner, “Could dramatically lower the cost of hydrogen cars.”
It would be useful in urban or rural areas, or even on remote battlefields, giving users the ability to make both electricity and fuel from the same device. In cities, it could store surplus energy from electrical grids, and in more remote locations, allow energy generation and fuel creation “off the grid.”
The pair’s replica of the device looks like a designer electronic gizmo encased in a turquoise plastic case. It uses inexpensive, abundant elements like nickel, iron and cobalt to produce both electrical energy and make hydrogen fuel. This two-fold output could power things in real time and store fuel for later use.
KANER AND EL-KADY’S DEVICE IN SMALL, PROTOTYPE SIZE. “PEOPLE NEED FUEL TO RUN THEIR VEHICLES AND ELECTRICITY TO RUN THEIR DEVICES,” KANER SAID. “NOW YOU CAN MAKE BOTH ELECTRICITY AND FUEL WITH A SINGLE DEVICE.” PHOTO: REED HUTCHINSON/UCLA
Kaner and El-Kady added a third electrode to the two normally found on fuel cells and supercapacitors. Normal positive and negative electrodes are supplemented by a dual-acting item that acts as both a supercapacitor (for energy storage) and as a water splitter separating hydrogen and oxygen in a process called water electrolysis.
UCLA explains, “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.”
An added bonus, “The device… produces hydrogen fuel in an environmentally friendly way. Currently, about 95 percent of hydrogen production worldwide comes from converting fossil fuels such as natural gas into hydrogen — a process that releases large quantities of carbon dioxide into the air,” according to El-Kady.
“’Hydrogen energy is not ‘green’ unless it is produced from renewable sources,’ El-Kady said. He added that using solar cells and abundantly available elements to split water into hydrogen and oxygen has enormous potential for reducing the cost of hydrogen production and that the approach could eventually replace the current method, which relies on fossil fuels.”
DEVICE CAN CHARGE INTERNAL SUPERCAPACITOR WHILE ALSO SPLITTING WATER INTO OXYGEN AND HYDROGEN
To increase the device’s surface area exposed to water, the team designed the electrodes at the nanoscale — thousands of times thinner than the thickness of a human hair. This increases the amount of hydrogen the device can produce and also stores more charge in the supercapacitor. Kaner says it will be possible to make versions larger than the prototype shown here because the components are inexpensive.
Mir Mousavi, a co-author of the paper and a professor of chemistry at Iran’s Tarbiat Modares University, says, “For hydrogen cars to be widely used, there remains a need for a technology that safely stores large quantities of hydrogen at normal pressure and temperature, instead of the pressurized cylinders that are currently in use.”.
Kaner compares the combination supercapacitor/water splitter to the first time a phone, web browser and camera were combined into a smartphone. He thinks this may even lead to new applications the researchers haven’t considered yet.
The paper’s other co-authors are graduate student Yasin Shabangoli and postdoctoral scholars Abolhassan Noori and Mohammad Rahmanifar, all of Tarbiat Modares.
Their paper, “An integrated electrochemical device based on earth-abundant metals for both energy storage and conversion,” appears in the September 27 issue of Energy Storage Materials.