CUI Junpeng ^1,3, LUO Linghong^1,3, WANG Leying ^1,3, CHENG Liang ^{2 ,3}, XU Xu ^1,3

(1. School of Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China; 2. National Engineering Research Center for Domestic & Building Ceramics Jingdezhen Ceramic University, Jingdezhen 333001, Jiangxi, China; 3. Jiangxi Provincial Key Laboratory of Fuel Cell Materials and Devices, Jingdezhen Ceramic University, Jingdezhen 333001, Jiangxi, China)

Abstract: The development and preparation of high-performance electrolyte materials will promote the commercialization of proton conductor solid oxide fuel cell (PCFC). BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ(BZCYYb) is a promising PCFC electrolyte material, which has sufficient chemical stability and high ionic conductivity in low and intermediate temperature range (400–700 ℃). However, the low sintering activity of BZCYYb hinders its application in PCFC. BZCYYb powder was synthesized by using an improved Pechini method, with inorganic salt Li₂CO₃ as the sintering aid, which was introduced using a mechanical ball milling mixing process. The addition of Li₂CO₃ significantly promoted densification process of the electrolyte, without changing the crystalline structure and phase composition of BZCYYb. After adding 8 mol% Li₂CO₃ and sintering at 1350 ℃ for 3 h, the sample exhibited relative density and linear shrinkage of 95.37% and 17.90%, respectively. The sample with 8 mol% Li₂CO₃ had the highest conductivity in wet hydrogen gas, reaching 1.922×10⁻² S·cm⁻¹ at 700 ℃, while the BZCYYb sample sintered at 1450 ℃ for 5 h had a conductivity of 1.493×10⁻² S·cm⁻¹. The introduction of an appropriate amount of Li₂CO₃ can significantly reduce the sintering temperature of BZCYYb, with desirable increment in the conductivity.
Key words: BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ proton conductor; sintering performance; conductivity; Li₂CO₃