Showcasing the Potential of Iron-Doped Electrolytes to Enhance the Ionic Conduction for a Low-Temperature Ceramics Fuel Cell

In recent studies, fast ionic conduction through doping and coating is a favorite subject and indicated a promising and stable strategy to optimize ions in the developed electrolytes for low-temperature ceramic fuel cells (LT-CFCs). Using the sol-gel technique, we designed a doped spinel electrolyte (Fe-CoAl₂O₄) to further enhance ionic properties. The prepared CFA (CoFe_0.25Al_1.75O₄) was used as an electrolyte sandwiched between symmetrical electrodes and delivered stunning fuel cell performance (810 mW/cm²) with better stability at the low operating temperature of 520 °C compared to other compositions of CFA. The low grain boundary resistance manifests CFA’s high ionic conduction + microstructural properties, assisting with higher fuel cell performance. The appropriate doping of Fe reduces the energy bandgap, enhancing the charge transport through energy band alignment. Moreover, the Schottky junction phenomena were proposed to support high ionic conduction without any short-circuiting issue. This work thus points out an exciting electrolyte with a different working mechanism from previous studies. It indicates a feasible approach to developing high-performing and stable electrolytes for LT-CFCs.