A fuel flexible defect-engineered lithium-nickel oxides anode for high-performance low-temperature solid oxide fuel cells

Low-temperature solid oxide fuel cells (LT-SOFCs) offer efficient and fuel-flexible energy conversion but require reduced operating temperatures to enable cost-effective and durable deployment. Here, we investigate three LiNiO₂-based electrodes N10-1 (LiNiO₂), N10-4 (Li_0.95NiO₂), and Al-doped Ni-9 (10 wt% Al₂O₃-modified LiNiO₂) as anode materials for LT-SOFCs. Structural and vibrational analyses reveal that lithium deficiency induces lattice disorder and phonon softening, while Al substitution regulates local bonding environments. SEM and XPS measurements indicate distinct particle morphologies and surface oxygen chemistries, with Ni-9 exhibiting stabilized Ni3+ states and modified non-lattice oxygen contributions. Electrochemical testing demonstrates that Ni-9 delivers enhanced electrochemical transport behavior and peak power densities (PPDs) of 665 mW cm−2 (H₂), 568 mW cm−2 (C₃H₈), and 388 mW cm−2 (CH₄) at 550 °C, outperforming N10-1 and N10-4. These results demonstrate that Al₂O₃-modified LiNiO₂-based anodes achieve functional electrochemical stability and fuel-flexible performance, providing a promising pathway toward low-temperature SOFC operation.