The effect of sintering aids on BaCe0middot7Zr0middot1Y0.1Yb0.1O3-d as the electrolyte of proton-conducting solid oxide electrolysis cells

Proton-conducting solid oxide electrolysis cells (H-SOECs) are attracting attentions of re-searchers due to their unique advantages. The proton-conducting material BaCe0.7Zr0.1-Y0.1Yb0.1O3-d (BZCYYb) has both the advantages of barium ceria-based and barium zirconate-based materials. BZCYYb material usually is synthesized by solid-state reaction (SSR) method, hence the densification of this electrolyte material is the key to restrict the application of H-SOECs. In this paper, effects of adding 1 wt% of different sintering aids (NiO, CuO, ZnO) to BZCYYb on the grain size and the conductivity are investigated. After adding 1 wt% of NiO and CuO sintering aids, BZCYYb electrolyte achieves ideal density. The electrical conductivity of four samples (BZCYYb without adding sintering aid, BZCYYb with wt% NiO, CuO, ZnO, respectively) is tested under different steam concentrations of air, nitrogen, hydrogen, and nitrogen-hydrogen mixture. The conductivity increased after the sintering aid is added. With the increase of steam concentration, the conductivity decreased slightly and then increased due to electron holes under oxygen atmosphere with steam at high temperature. In other atmospheres, the conductivity increases with the steam concentration. In the atmosphere of 20 vol% H2O-Air and H2, the conductivity of the BZCYYb samples with 1 wt% CuO is about 1.087 x 10-2 S cm -1 and 9.02 x 10-3 S cm -1 at 650 degrees C, and the conductivity of the BZCYYb samples with 1 wt% NiO is 1.277 x 10-2 S cm -1 and 8.24 x 10-3 S cm -1, respectively. However, compared with NiO, CuO has advantages in promoting hydration reaction and proton conduction of BZCYYb electrolyte.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Proton-conducting solid oxide electrolysis cells (H-SOECs) using BZCYYb as the electrolyte material have unique advantages. This study investigates the effects of adding different sintering aids (NiO, CuO, ZnO) to BZCYYb on grain size and conductivity. The results show that adding 1 wt% of NiO and CuO sintering aids improves the density and conductivity of BZCYYb. The conductivity increases with steam concentration in most atmospheres, while in oxygen atmosphere with steam at high temperature, the conductivity initially decreases slightly and then increases. CuO is found to have advantages in promoting hydration reaction and proton conduction of BZCYYb electrolyte compared to NiO.