Investigation on LiNaSO4–Al2O3 ceramics as electrolytes for H2/O2 fuel cells

LiNaSO4–Al2O3 ceramic composites were prepared for use as electrolytes in H2/O2 fuel cells. TG/DTA, XRD, and FT-IR studies on the structure and phase composition of the materials indicated no obvious chemical reaction between LiNaSO4 and α-Al2O3 during heat treatment up to 800°C. The concentration of surface defects increased because of addition of α-Al2O3, which enhanced the ionic conduction of the materials. When a proper amount of α-Al2O3 was added, the conductivity of LiNaSO4–Al2O3 reached 10−2 S/cm below the phase transition temperature (515°C) of LiNaSO4 and 10−1 S/cm above it. H2/O2 fuel cells using LiNaSO4–Al2O3 as an electrolyte showed an open circuit voltage of 1.3 V and a current density of 280 mA/cm2 at 0.35 V terminal voltage. However, the rapid degradation of the cell performance implies that the materials may be unstable in the operational condition of fuel cells.