High-Temperature Proton Conduction in LaSbO₄

Area of Science:

• Solid-state chemistry
• Materials science
• Protonic conductivity

Background:

• Lanthanum orthoantimonate is a material with potential applications in electrochemical devices.
• Investigating protonic conductivity in novel oxide materials is crucial for developing advanced energy technologies.

Purpose of the Study:

• To synthesize lanthanum orthoantimonate using a solid-state method.
• To investigate the potential for enhanced protonic conductivity through calcium doping.
• To characterize the structural and electrical properties of the synthesized materials.

Main Methods:

• Solid-state synthesis for lanthanum orthoantimonate and Ca-doped variants.
• X-ray diffraction for structural analysis.
• Dilatometry for thermal expansion studies.
• Electrical conductivity measurements in varying humidity and H/D isotope exchange experiments.

Main Results:

• Single-phase lanthanum orthoantimonate and Ca-doped samples were successfully synthesized, crystallizing in the P2₁/n space group.
• Non-linear thermal expansion was observed, with a linear thermal expansion coefficient of 9.56×10^-6 K^-1.
• Protonic conductivity was confirmed under oxidizing conditions, with conductivity peaking at ~10^-6 S cm^-1 at 800°C.

Conclusions:

• This study reports for the first time protonic conductivity in lanthanum orthoantimonates.
• Calcium doping shows potential for optimizing protonic conductivity, although further improvements via microstructure and doping are needed.
• Lanthanum orthoantimonate is a promising candidate for proton-conducting materials, warranting further research.