Evaluation of lanthanum tungstates as electrolytes for proton conductors Solid Oxide Fuel Cells

Comparison of the local and the average crystal structure of proton conducting lanthanum tungstate and the influence of molybdenum substitution

“…1 LWO is a relatively pure proton conductor at low and intermediate temperatures and can therefore be used as an electrolyte in proton-conducting solid oxide fuel cells. [2][3][4][5] At higher temperatures, the material exhibits additional p-type and n-type electronic conductivities under oxidizing and reducing conditions, respectively. 2,3,6 The material can, under reducing conditions, be used as a dense membrane for hydrogen separation due to the ambipolar transport of protons and electrons.…”

Solid oxide proton conductors beyond perovskites

“…La6WO12 is also chemically and mechanically compatible with conventional cathode materials such as La0.7Sr0.3MnO3-δ (LSM) and La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) and chromite anode perovskites such as La0.85Sr0.15Cr0.9Ni0.1O3−δ (LSCN) and La0.75Ce0.1Sr0.15CrO3−δ (LSCCe), while it reacts with BSCF 250,251,252,253 . Fuel cells with La6WO12-based electrolytes display open circuit voltage (OCV) values close to the theoretical Nerst voltage, although delivering only modest power densities ( 50 mW cm −2 at 700 °C) 244,251,254 . Due to the presence of mixed protonic and electronic conduction at T > 700 °C, La6WO12-based materials have also been investigated for application as high temperature hydrogen separation membranes, which constitute an interesting solution for the recovering of H2 from low-quality gases 255 .…”

Effect of Nb Doping on Hydration and Conductivity of La27W5O55.5−δ

“…The relatively high σ ion of La 27 (W 0.85 Nb 0.15 ) 5 O 55.5−δ compared to other lanthanum tungstate compounds, thus makes it a better candidate as an electrolyte material for fuel cells. The fuel performance of these Nb containing lanthanum tungstates has been tested and power densities of 140 and 18 mW/cm 2 at 900°C and 650°C were, respectively, reported . The proton conductivity is relatively high compared to other lanthanum tungstates, but it is still lower than state‐of‐the‐art perovskite‐structured proton conductors, such as yttrium‐doped BaCeO 3 or BaZrO 3.…”