Proton-conducting -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 gamma-MnO2 based heterostructure electrolyte composing with gadolinium-doped ceria (GDC). The electrochemical proton injection into the gamma-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 gamma-MnO2-GDC heterostructure composite exhibits an ionic conductivity of 0.2 S cm(-1) at 520 degrees 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 degrees C has been demonstrated. The work highlights the potential of the gamma-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.