Scientists at Kyushu University have developed a solid-oxide fuel cell that operates efficiently at 300°C, a significant reduction from the typical 700-800°C. This breakthrough uses scandium-doped oxides to enable fast proton transport without lattice clogging. The innovation could lower costs and accelerate hydrogen power adoption.
Solid-oxide fuel cells (SOFCs) promise efficient, long-lasting electricity generation from hydrogen, producing only water as a byproduct. However, their high operating temperatures of 700-800°C demand heat-resistant materials, driving up expenses and limiting widespread use.
Researchers at Kyushu University addressed this challenge by engineering electrolytes that conduct protons rapidly at just 300°C. As reported in Nature Materials, the team doped barium stannate (BaSnO3) and barium titanate (BaTiO3) with high levels of scandium (Sc), achieving proton conductivity above 0.01 S/cm—comparable to conventional SOFCs at 600-700°C.
Professor Yoshihiro Yamazaki, who led the study, explained the innovation: "Bringing the working temperature down to 300°C would slash material costs and open the door to consumer-level systems." The key lies in the crystal lattice: scandium atoms form a 'ScO6 highway' of linked oxygens, creating a wide, softly vibrating pathway that allows protons to move freely without trapping.
Yamazaki noted the prior dilemma: "Adding chemical dopants can increase the number of mobile protons passing through an electrolyte, but it usually clogs the crystal lattice, slowing the protons down." Structural analysis and simulations confirmed that these 'softer' oxides absorb more scandium than traditional materials, resolving the trade-off.
This advancement not only targets affordable SOFCs but also extends to low-temperature electrolyzers, hydrogen pumps, and CO2 conversion reactors. Yamazaki concluded: "Our work transforms a long-standing scientific paradox into a practical solution, bringing affordable hydrogen power closer to everyday life."
The findings appear in the journal article: Kota Tsujikawa et al., "Mitigating proton trapping in cubic perovskite oxides via ScO6 octahedral networks," Nature Materials, 2025; 24(12):1949, DOI: 10.1038/s41563-025-02311-w.