The growing demand for electricity – driven by electric vehicles, portable electronics, and AI-based technologies – has intensified the search for efficient and clean energy conversion systems. Solid oxide fuel cells (SOFCs) offer a promising solution due to their high efficiency, fuel flexibility, and low emissions. However, their widespread adoption has been limited by the sluggish oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) kinetics at the cathode and anode relying on cobalt-based materials, which suffer from high thermal expansion and high cost.
Now, a research team led by Professor Ling Huang at Xinjiang University, China, has developed a novel cobalt-free electrode material that overcomes these limitations. The work was published in Nano Research on August 20, 2026. Intentionally doping larger Ca 2+ ions (Ca 2+ , r = 1.34 Å) i into the smaller Sm 3+ (r = 1.24 Å) sites of the iron-based double perovskite SmBaFe 2 O 5+ δ (SBF) reduces the ionic radius mismatch between Sm 3+ and Ba 2+ (r = 1.61 Å), widens the Fe-O-Fe bond angle from 162° to 168° and shortens the Fe-O bond length from 1.9898 Å to 1.9675 Å. These structural changes significantly optimize electron transport pathways, enhance oxygen vacancy concentration, and improve electrical conductivity. At 800 °C, the resulting material – Sm 0.9 Ca 0.1 BaFe 2 O 5+ δ (SCBF) – achieved a 91% increase in electrical conductivity (from 5.98 to 11.42 S·cm⁻ 1 ) and a 40% reduction in polarization resistance (from 0.106 to 0.066 Ω·cm 2 ). When used as a cathode in a single cell, SCBF delivers a peak power density of 2.14 W·cm⁻ 2 . In a symmetrical SOFC configuration – where SCBF serves as both the cathode and anode – the cell still offers a high-power density of 1.18 W·cm⁻ 2 . The cell also shows excellent long-term stability (over 200 hours) and robust thermal cycling durability (20 cycles).
This work provides a fresh angle for the design of high-performance, cobalt-free, and cost-effective electrode materials for SOFCs. The team anticipates that this strategy can be extended to other functional materials, paving the way to more sustainable and practical SOFC technologies.
This work was supported by the Xinjiang Autonomous Region Key Research Project (No. 2022D01D31) and the Key Program of the National Natural Science Foundation of China (No. 22435003).
DOI Link:
https://doi.org/10.26599/NR.2026.94908918
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Improved Oxygen Kinetics on both Cathode and Anode of SmBaFe₂O₅₊δ-Based Solid Oxide Fuel Cells through Ca²⁺ Doping
20-Aug-2026