LSCF-WO₃ semiconductor composite electrolytes for low-temperature solid oxide fuel cells

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Solid oxide fuel cells (SOFCs) are promising energy conversion devices.
• Low-temperature SOFCs (LTSOFCs) require electrolytes with high ionic conductivity.
• Lanthanum strontium cobalt ferrite (LSCF) is a known material for SOFCs, but its performance can be limited.

Purpose of the Study:

• To develop and evaluate a novel composite electrolyte for LTSOFCs.
• To investigate the effect of WO3 addition on LSCF electrolyte properties.
• To optimize the composition for enhanced fuel cell performance.

Main Methods:

• Fabrication of La_0.6Sr_0.4Co_0.2Fe_0.8O_3- (LSCF)-WO₃ composite electrolytes.
• Electrochemical testing of LTSOFCs utilizing the composite electrolyte.
• Analysis of ionic and electronic conductivity using electrochemical impedance spectroscopy.
• Surface characterization using X-ray photoelectron spectroscopy (XPS).

Main Results:

• The 8LSCF-2WO₃ composite electrolyte achieved a maximum power density (P_max) of 812 mW cm^-2.
• The open-circuit voltage (OCV) exceeded 1.0 V, indicating no short-circuit issues.
• Oxygen ionic conductivity of the 8LSCF-2WO₃ composite reached 0.337 S cm^-1, significantly higher than pure LSCF.
• XPS analysis revealed increased oxygen vacancy content at the LSCF-WO₃ heterointerface, contributing to enhanced ionic conductivity.

Conclusions:

• The LSCF-WO₃ composite electrolyte effectively enhances LTSOFC performance.
• The addition of WO₃ suppresses electronic conductivity and boosts ionic conductivity of LSCF.
• The optimized 8LSCF-2WO₃ composition offers a promising pathway for efficient LTSOFCs.