Synthesis and Evaluation of LaBaCo_2-MoO₅₊ Cathode for Intermediate-Temperature Solid Oxide Fuel Cells

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Solid oxide fuel cells (SOFCs) require efficient cathode materials for intermediate-temperature operation.
• LaBaCo2O5+delta (LBCM) is a promising perovskite-structured material, but its performance can be further improved.

Purpose of the Study:

• To investigate the effect of molybdenum (Mo) doping on the properties of LaBaCo2-xMoxO5+delta (LBCMx) cathodes.
• To evaluate the performance of LBCMx cathodes in intermediate-temperature SOFCs.

Main Methods:

• Sol-gel synthesis of LBCMx powders with varying Mo content (x = 0-0.08).
• Characterization of thermal expansion coefficient, electrical conductivity, and electrochemical performance (polarization resistance).
• Fabrication and testing of single SOFCs utilizing LBCMx cathodes and YSZ electrolytes.

Main Results:

• The solid solubility limit of Mo in LBCMx was found to be below x = 0.08.
• Increasing Mo content from x = 0 to 0.06 decreased the thermal expansion coefficient from 20.87 × 10^-6 K^-1 to 18.47 × 10^-6 K^-1.
• Electrical conductivity increased from 464 S cm^-1 to 621 S cm^-1 at 800 °C with Mo doping.
• The optimal cathode, LBCM0.04, exhibited a polarization resistance of 0.036 Ω cm^2, a 1.67-fold reduction compared to the undoped cathode.
• Maximum power density improved from 165 mW cm^-2 to 248 mW cm^-2 at 800 °C.

Conclusions:

• Molybdenum doping is an effective strategy to enhance the performance of LBCM cathodes for intermediate-temperature SOFCs.
• Optimized LBCMx cathodes offer improved thermal compatibility, higher conductivity, and reduced polarization resistance.
• The enhanced electrochemical properties of LBCMx cathodes lead to significantly improved SOFC power density.