Tuning Li─O/Na─O Bonding Environments via Na + /F − Co‐Doping to Boost Electrode Activity and Durability in SOFCs Operating at 310°C

ABSTRACT The major challenges in low‐temperature solid oxide fuel cells (LT‐SOFCs) are poor electrode activity under 600°C, cell failure below 400°C and insufficient durability. Herein, we develop a Na + /F − co‐doped LiNi 0.8 Co 0.15 Al 0.05 O 2‐δ (LNCA) electrode strategy that synergistically regulates the Li ─ O/Na ─ O bonding environments to overcome these challenges. Density functional theory (DFT) calculations reveal that Na + /F − co‐doping not only strengthens Li ─ O/Li ─ F bonds to stabilize the layered framework, but also weakens Na ─ O bonds, lowering the Na + migration barrier and enabling selective Na + migration. The upshifted Ni d‐band center combined with strong hybridization of F‐2p/Ni‐3d near the Fermi level enhances the electrode activity. Quantitative analysis results reveal that Na + /F − co‐doping leads to a significantly increased Na/Li ratio, while thermal analysis results validate that Na + /F − co‐doping reduces the melting point of the (Na, Li) hydroxide/carbonate complex to 334°C. Furthermore, the R p is as low as 0.307 Ω·cm 2 at 520°C, indicating dramatically improved electrode kinetics. Consequently, Na + /F − co‐doping lowers the operating temperature of LT‐SOFCs to 310°C and achieves a durability of 135 h at 520°C, marking the lowest operational temperature reported for LT‐SOFCs to date. These findings provide critical insights into electrode modification and hold enormous potential for advancing LT‐SOFCs development.