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 0.5 Sr 0.5 CoCuO 5+δ were tuned to match the electrolyte by incorporating a chemically-compatible NTE material: Sm 0.85 Zn 0.15 MnO 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. • Negative thermal expansion material applied to tune high-performance electrodes. • The origin of SZM15 negative thermal expansion was studied by different techniques. • Different wt% of SZM15 used as an additive to engineer heterostructured cathodes. • Electrospun nanofibrous heterostructured electrode exhibits superior performance. • Power density of 850 mW·cm −2 at 800 °C was achieved, giving 40 % increase.