Unlocking intermediate-temperature fuel cell potential with Ni 0.4 C u0.6 Mn 2 O 4 spinel oxides

Abstract Ni 0.4 Cu 0.6 Mn 2 O 4 , an inverse spinel oxide, is studied as a potential anode for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to its mixed ionic–electronic conductivity, redox stability, and fuel flexibility. Prepared via sol-gel and calcined at 900 °C, it forms a stable cubic spinel structure with a porous morphology compatible with doped ceria electrolytes. The structure incorporates Mn³⁺/Mn⁴⁺, Ni²⁺, and Cu²⁺ across tetrahedral and octahedral sites, promoting small polaron hopping and oxygen vacancy formation under reducing conditions. These features enhance charge mobility over a wide temperature range. Electrical conductivity reaches 12.1 S cm⁻¹ at 800 °C in air and exceeds 5 S cm⁻¹ in hydrogen. Symmetrical cell tests yield an area-specific resistance of 0.32 Ω cm² at 750 °C in humidified hydrogen. The material shows methane tolerance with minimal carbon deposition, supporting hydrocarbon fuel use. These functional traits result from cationic redox behaviour and controlled microstructure. Compared to Ni–YSZ, it resists carbon fouling and thermal degradation more effectively. However, full-cell performance, interfacial compatibility, and long-term stability remain untested. Future work must benchmark these parameters to assess practical viability for IT-SOFC deployment.