Stable and active nanofiber electrodes tuned via a negative thermal expansion strategy for designing high-performance solid oxide fuel cells

Thermal mismatch between the electrode and electrolyte is a key limitation hindering the commercial application of solid oxide fuel cells. This issue can be solved by state-of-the-art negative thermal expansion materials (NTEs), enabling the fabrication of thermally stable electrodes. Herein, for the first time, we report successful fabrication of in situ-assembled heterostructured nanofiber electrode incorporating an NTE material, using the electrospinning technique. The thermomechanical properties of SmBa_0.5Sr_0.5CoCuO_5+δ were tuned to match the electrolyte by incorporating a chemically-compatible NTE material: Sm_0.85Zn_0.15MnO_3−δ (SZM15). The polarization resistance at 800°C of the electrode with 10 wt% addition SZM15 decreased by ∼55 % compared to the pristine cathode, resulting in a good peak power density of 850 mW·cm⁻², approximately 40 % higher than in the pristine cell. These results present a novel strategy for designing stable and active nanofiber electrodes by tuning thermomechanical properties through the incorporation of NTE materials, thereby enhancing cell performance and ensuring durability.