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Storing Electricity in the Form of Chemical Bonds: An Alkaline Exchange Membrane Unitized Regenerative Fuel Cell

Thomas Jaramillo and Curtis Frank, Chemical Engineering

This team is researching a new technological concept that may hold promise by storing renewable electricity affordably in the form of chemical bonds. The device the researchers are developing is an alkaline anion exchange membrane unitized regenerative fuel cell (AEM-URFC). Such a device has never been demonstrated previously. The AEM-URFC serves to store energy by using renewable energy to split water into H2 and O2 when renewable electricity is available. During times when wind or solar resources are not available, the H2 and O2 are recombined to produce water once again, providing electricity to the grid in the process.

Though acidic URFCs have been demonstrated previously, the corrosive environment requires precious metal catalysts that substantially increase the cost of the device. In the alkaline environment of our new AEM-URFCs, the researchers can avoid precious metals altogether. The team is researching non-precious metal catalysts and functional alkaline membranes that can work together in this device.

The researchers have developed the first working prototype of a precious-metal free, low temperature AEM-URFC. They have cycled it eight times between electrolyzer mode and fuel cell mode demonstrating reasonable durability with round-trip efficiencies of 34-40% throughout cycling. The team is now working to improve the key components of the AEM-URFC, namely the catalysts and the membrane, in order to boost device performance for both round-trip efficiency and durability.

Publications and media:

"A semi-interpenetrating network approach for dimensionally stabilizing highly-charged anion exchange membranes for alkaline fuel cellsChemSusChem8 (2015): 1472–1483.

"Facilitating hydroxide transport in anion exchange membranes via hydrophilic graftsJournal of Materials Chemistry A 2 (2014): 16489-16497.

"Nickel–silver alloy electrocatalysts for hydrogen evolution and oxidation in an alkaline electrolyte" Phys. Chem. Chem. Phys.16 (2014): 19250-19257.

"A carbon-free, precious-metal-free, high-performance O2 electrode for regenerative fuel cells and metal–air batteries" Energy & Environmental Science 7 (2014): 2017-2024.

 

 

Awarded 2011 as part of the TomKat's Large-Scale Solar project.