Proton-conducting γ-MnO₂ based heterostructure composite electrolyte for protonic ceramic fuel cells

Proton-conducting electrolyte materials are essential for the development of high-performance protonic ceramic fuel cells (PCFCs). This work investigates the proton conduction property of a γ-MnO₂ based heterostructure electrolyte composing with gadolinium-doped ceria (GDC). The electrochemical proton injection into the γ-MnO₂-GDC composite electrolyte is thoroughly studied using various characterization techniques, including infrared (IR) and Raman spectroscopy, and EIS with distribution of relaxation times (DRT) analysis. The optimized γ-MnO₂-GDC heterostructure composite exhibits an ionic conductivity of 0.2 S cm⁻¹ at 520 °C during fuel cell operation and proton conduction dominating the ion conduction is confirmed by proton filtering cell. Excellent fuel cell performance with a maximum power density of 896 mW cm⁻² at 520 °C has been demonstrated. The work highlights the potential of the γ-MnO₂ based heterostructure composite as a proton-conducting electrolyte material for advanced PCFCs, offering new prospects for the development of cost-effective and efficient energy conversion technologies.