As the global push for cleaner energy intensifies, solid oxide fuel cells have emerged as a promising option. They turn hydrogen or other renewable fuels directly into electricity and heat without combustion, eliminating virtually all pollution and boosting efficiency to over 60%. But a major downside has kept them out of everyday commercial use: they require extremely high temperatures to operate.
A team of researchers at UT San Antonio and partnering institutions have found a way around that barrier. Instead of relying on perfectly ordered materials, they applied a thermal shock technique to create tiny clusters of disordered atoms that move oxygen ions much more easily at lower temperatures. The result could help make fuel cells cheaper, more durable and easier to use outside the lab.
“The golden rule has been that you need a perfect crystal lattice for fast ion movement,” said Chonglin Chen, PhD, a professor in the Department of Physics and Astronomy in the College of Sciences. “What we have done here challenges that assumption.”
The team recently published their findings in Science Advances, with Shengli Pang, a Jiangsu University researcher and member of Chen’s team, serving as the lead author.
The sub-400°C breakthrough
Conventional solid oxide fuel cells (SOFCs) operate “inadequately” at temperatures lower than 400 degrees Celsius, making them incredibly difficult to use in commercial settings, Chen explained.
Conventional SOFCs need extreme temperatures, often exceeding 700°C, to operate. These volcanic temperatures accelerate material breakdown, demand expensive heat-resistant components to contain the heat, and cause long startup delays.
To solve this problem, the team turned to molecular nanotechnology, using extreme temperature swings to create materials with helpful imperfections at the atomic level. First, they baked a standard ceramic fuel cell material at a scorching 1,300°C. They then rapidly froze it through a technique called quenching — plunging it into liquid nitrogen at nearly –196°C. This violent temperature shock shatters the material’s rigid, glass-like structure into ultra-thin, microscopic clusters of atoms measuring just 0.63 nanometers thick — so small that thousands of them could stack across the width of a single human hair.
Chen said the idea came from steelmaking, where quenching is used to change the material’s structure. The team adapted that approach for ceramics and found that the resulting clusters conducted oxygen ions far better than expected.
When tested at 400°C, the material achieved record oxygen-ion conductivity, about 1,400 times higher than a conventional ceramic material.
The chaos advantage
The breakthrough challenges a longstanding assumption in materials science that the best conductors must have a perfectly ordered, rigid crystal structure, with the neat rows of atoms acting like well-defined lanes on a highway.
But when the team examined their new material with electron microscopes and X-ray analysis, they found that the atoms inside these tiny fragments were disordered and chaotic. Yet they were still performing well.
This is because in traditional materials, the atomic-scale paths eventually become blocked as atoms clump together under stress, creating bottlenecks that interrupt the energy flow. But inside the new, disordered nanoclusters were oxygen vacancies that stayed separate and active, while interacting to create a network that allowed ions to travel more freely.
“With these vacancy-isolated clusters, we created a chaotic, highly dynamic network where the oxygen vacancies remain independent,” Chen explained. “Instead of fighting the disorder, we are using it to create a kind of superhighway for the ions.”
What this means for clean energy
To demonstrate commercial viability, the team tested whether the material could improve real fuel cell performance. By blending a trace amount of the clusters — just 0.5% by weight — with a conventional cobalt-based fuel cell cathode, they tripled the fuel cell’s peak power output.
In addition to boosting power, the clusters also boost durability. Standard fuel cells degrade quickly, losing over 13% of their power every 100 hours of use under the intense stress of high temperatures. But fuel cells enhanced with the disordered nanoclusters became 3.4% more stable and efficient with continued use.
“It acts as an atomic shield, boosting power while actively stopping the degradation that normally kills these devices,” Chen said.
Chen believes that the method could be easy for manufacturers to adopt because it requires only a small amount of the new material rather than a complete redesign of existing systems. They are now working on ways to scale up production.
“This will bring us one step closer to practical, next-generation green energy,” Chen added.
