Effect of Sintering Additives on Sintering Behavior and Conductivity of BaZr0.1Ce0.7Y0.2O3-δ Electrolytes

doi:10.15541/jim20240328

Abstract

Abstract:

As one of the typical electrolyte materials for proton conducting solid oxide fuel cells, BaZr_0.1Ce_0.7Y_0.2O_3-_δ (BZCY) possesses advantages such as high proton conductivity and stability. However, sintering activity of BZCY electrolyte is poor, usually requiring high sintering temperature for densification, which is inconducive to the preparation and application in cells. This study aimed to reduce the sintering temperature of BZCY electrolyte and explore the influence of sintering additives such as NiO, Fe₂O₃, ZnO, and CuO on the sintering characteristics of BZCY in detail. The results indicate that the oxides except Fe₂O₃ can effectively promote the grain growth of BZCY sintered body. Among them, the addition of CuO has the most significant promoting effect on the sintering process of BZCY. After adding 2% (in mass) CuO into BZCY (BZCY-2%CuO), even if the sintering temperature was reduced to 1250 ℃, the relative density of the sintered body still maintained higher than 98%. Additionally, the conductivity of BZCY-2%CuO was up to 2.7×10^-2 S·cm^-1 at 600 ℃ in wet H₂ atmosphere, which was nearly 5 times higher than that in wet air. More importantly, BZCY-2%CuO electrolyte exhibits negligible electronic conductivity under cell operating conditions while maintaining excellent stability.

Key words: proton conducting solid oxide fuel cell, BaZr_0.1Ce_0.7Y_0.2O_3-_δ, electrolyte, sintering additive, sintering behavior, conductivity

CLC Number:

TQ174

ZHANG Jinghui, LU Xiaotong, MAO Haiyan, TIAN Yazhou, ZHANG Shanlin. Effect of Sintering Additives on Sintering Behavior and Conductivity of BaZr_0.1Ce_0.7Y_0.2O_3-_δ Electrolytes[J]. Journal of Inorganic Materials, 2025, 40(1): 84-90.

Figures/Tables 8

Fig. 1 XRD patterns of BZCY bulks with different sintering aids

Fig. 2 Surface and cross-section morphologies of BZCY samples with different sintering aids Surface: (a) BZCY-2%Fe2O3, (c) BZCY-2%ZnO, (e) BZCY-2%NiO, and (g) BZCY-2%CuO; Cross-section: (b) BZCY-2%Fe2O3, (d) BZCY-2%ZnO, (f) BZCY-2%NiO, and (h) BZCY-2%CuO

Fig. 3 Relative densities of BZCY samples with different sintering aids

Fig. 4 Surface and cross-section morphologies of BZCY-x%CuO (x=1, 2, 3) bulks sintered at 1250 ℃ Surface: (a) BZCY, (c) BZCY-1%CuO, (e) BZCY-2%CuO, and (g) BZCY-3%CuO; Cross-section: (b) BZCY, (d) BZCY-1%CuO, (f) BZCY-2%CuO, and (h) BZCY-3%CuO

Fig. 5 Relative densities of BZCY-x%CuO (x=1, 2, 3) bulks sintered at 1250 ℃

Fig. 6 Typical impedance spectra of BZCY-2%CuO (a) Full spectra; (b) Enlarged area in dotted frame of (a)

Fig. 7 Conductivities of BZCY-x%CuO samples under different conditions (a) Total conductivities of BZCY-x%CuO at 600 ℃; (b) Total conductivities at different temperatures in different atmospheres of BZCY-2%CuO; (c) Intracrystalline conductivities at low temperature of BZCY-2%CuO; (d) Grain boundary conductivities at low temperature of BZCY-2%CuO

Fig. 8 (a) Stability of the conductivity of BZCY-2%CuO at 600 ℃ and (b) OCV of the full cell with BZCY-2%CuO as electrolyte

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