West Virginia University engineers have achieved a significant breakthrough in energy storage and conversion, successfully developing and testing a novel fuel cell capable of seamlessly switching between electricity generation and storage while also producing hydrogen from water. This innovation is poised to enhance the flexibility and resilience of modern electrical grids, particularly in their integration of intermittent renewable energy sources like solar and wind power.

Unlike existing technologies, this protonic ceramic electrochemical cell (PCEC) design demonstrates exceptional stability and performance under the high heat and steam conditions typical of industrial-scale operations. The research directly addresses three critical limitations of current PCEC designs: instability in high-steam environments, weak inter-layer connections, and poor proton conductivity, according to Xingbo Liu, materials science professor and associate dean for research at the WVU Benjamin M. Statler College of Engineering and Mineral Resources.

Liu emphasized the market significance, stating that PCECs, with their dual energy storage and power production capabilities, could be a transformative technology for the U.S. electrical grid, which is increasingly challenged by the variable influx of energy from diverse sources. "Current PCEC designs are unstable in high steam environments, with weak connections between layers and they perform poorly at the critical task of conducting protons," Liu explained. In response, his team engineered a 'conformally coated scaffold' (CCS) design, featuring connected electrolytes and a sealed electrocatalyst layer that remains stable in steam, absorbs water, and maintains integrity across temperature fluctuations, facilitating efficient proton, heat, and electricity transfer.

Their prototype showcased remarkable durability, operating continuously for over 5,000 hours at 600 degrees Celsius and 40% humidity. This performance significantly surpasses previous benchmarks, with the prior longest continuous operation for a small PCEC being 1,833 hours, which also experienced performance degradation over time. "That technology wasn’t ready for large-scale applications," Liu noted. "By comparison, our conformally coated scaffold design did so well in both energy storage and energy production modes that we also built a test version of a system that uses CCS cells to store hydrogen and use it in electrolysis reactions. Our system stayed stable while switching smoothly and frequently back and forth between those modes, even over long 12-hour cycles. This is how we achieve balance in a power grid that’s evolving to incorporate intermittent, sustainable sources of energy."

The findings were published in a Nature Energy paper, co-led by Hanchen Tian, a WVU doctoral student and postdoctoral researcher at the time, and Wei Li, then a WVU research assistant professor. Tian highlighted the technical advancements, explaining that conventional PCEC designs often fail due to steam ingress into electrolytes and differential thermal expansion between layers. The WVU team mitigated these issues by incorporating barium ions to enhance water retention in the coating, facilitating proton movement, and nickel ions to produce larger, stable CCS cells. Crucially, the system's ability to run on water vapor means it can utilize saltwater or low-quality water, reducing operational costs and resource demands.

"All that shows promise for scaling up to industrial levels," Tian affirmed. "We showed that it’s possible to make, on a large scale, CCS fuel cells that will stay strong and stable under intense conditions." The project received funding from the U.S. Department of Energy and was recognized with the DOE Hydrogen Production Technology Award. The researchers are now collaborating with the WVU Office of Innovation and Commercialization to advance the design towards commercialization.