China Nonferrous Metallurgy

Solid oxide fuel cell (SOFC) electrolyte, a crucial channel for ion transport, plays a key role in reducing operating temperature and improving electrochemical efficiency of SOFC. According to the operating temperature of SOFC, the electrolyte materials are divided into high temperature electrolyte (＞850℃), medium temperature electrolyte (650~850℃) and low temperature electrolyte (＜650℃). Yttria-stabilized zirconia (YSZ) is the most widely used ion-conducting electrolyte in high-temperature electrolytes. Due to its limited oxygen-ion conductivity, the cell experiences rapid degradation at elevated temperatures. Both scandium stabilized zirconia (ScSZ) and LaGaO3-based electrolytes are suitable for intermediate temperature SOFC. The commercial viability of ScSZ electrolytes is constrained by prohibitively expensive raw materials. LaGaO3-based electrolyte is synthesized by various elements,which tends to form impurity phases, raising the materials internal resistance. Cerium oxide-based (GeO2) materials and bismuth oxide (δ-Bi2O3) materials with cubic fluorite structure have stable ionic conductivity at low temperature. However, both materials undergo reduction in redox conditions, causing electronic leakage and cell short-circuiting. BaCeO3-based proton conductors remain at an early development stage, with complex doping mechanisms requiring further optimization. Future electrolyte research must simultaneously address four critical challenges: temperature reduction, phase stabilization, conductivity enhancement, and production cost minimization.