Enhanced performance of solid oxide fuel cells using highly conductive Ca2+ and F− co-doped Gd0.2Ce0.8O1.9 buffer layer

Abstract

Gadolinium-doped ceria (GDC) is the most widely used buffer layer to prevent the reaction between YSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode for commercial solid oxide fuel cell (SOFC). However, conductivity and sintering activity are vital to cell performance. In this paper, Ca2+ and F− co-doped GDC (Ca0.03Gd0.17Ce0.8F0.06O1.84-δ, CGDCF) is used as a buffer layer to improve the performance and stability of SOFC. The co-doped F− and Ca2+ significantly improve the sintering properties and oxygen ion transport of traditional GDC material. Meanwhile, the optimized sintering temperature is 1300 °C, with the lowest ohmic resistance. The peak power density of a cell with a CGDCF buffer layer reaches 1.809 W cm−2 at 850 °C, which is 37 % higher than that of GDC. In addition, the cell with the CGDCF buffer layer exhibits excellent stability during the 150 h test owing to the lower migration of La and Sr elements. Thus, the Ca2+ and F− co-doped GDC oxide emerges as a promising material for buffer layer applications.