High performance solid oxide electrolysis cells using Pr_(0.8)Sr_(1.2)(Go,Fe)_(0.8)Nb_(0.2)O_(4+δ)-Go-Fe alloy hydrogen electrodes

摘要

A novel ceramic hydrogen electrode material consisting of K_2NiF_4-type structured Pr_(0.8)Sr_(1.2)(Co,Fe)_(0.8)Nb_(0.2)O_(4+δ) (K-PSCFN) matrix with homogenously dispersed nano-sized Co-Fe alloy (CFA) has been demonstrated by annealing perovskite Pr_(0.4)Sr_(0.6)Co_(0.2)Fe_(0.7)Nb_(0.1)O_3 δ (P-PSCFN) in H_2 at 900 ℃. Impedance spectra and voltage-current density curves of the La_(0.8)Sr_(0.2)Ga_(0.83)Mg_(0.17)O_3 δ(LSGM) electrolyte supported solid oxide electrolysis cell (SOEC) with a configuration of K-PSCFN-CFA/LSGM/Ba_(0.8)Co_(0.7)Fe_(0.2)Nb_(0.1)O_3 δ (BCFN) have been evaluated as a function of the operating temperature and feeding gas absolute humidity (AH) to characterize the cell performance. Cell polarization resistances (R_p) were as low as 0.77 and 0.31Ω cm~2 under open circuit voltage (OCV) and 60% absolute humidity (AH) at 800 and 900 ℃, respectively. The cell has demonstrated good stability for high temperature stream electrolysis, and a hydrogen production rate of 707 ml/cm~2 h calculated from the Faraday's law has been achieved under an electrolysis voltage of 1.3 V and 60 vol.% AH at 900 ° C. The cell performance results indicate that K-PSCFN-CFA is a promising hydrogen electrode for high temperature solid oxide electrolysis cells.