Planer type solid oxide cells using La0.9Sr0.1Ga0.8Mg0.2O3-δ thin-film electrolyte prepared by dip-coating method for high performance CO2/H2O co-electrolysis

Abstract

Ni-Zr_0.92Y_0.16O_2.08(YSZ)-supported solid oxide cell with La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ(LSGM) thin film as the electrolyte was prepared with dip-coating and co-sintering methods. CO₂/H₂O co-electrolysis and CO₂ electrolysis performance were studied. Initial performance measurement from 1073 to 773 K shows reasonably high open circuit voltage (OCV) with superior current densities, particularly in CO₂/H₂O co-electrolysis, up to −4.9 A/cm² at 1073 K and −0.19 A/cm² at 773 K. Product analysis suggests that H₂ and CO production was attributed to both electrolysis and the reverse water-gas shift (RWGS) reaction, with almost 100 % Faraday efficiency. The H₂/CO ratio in the product ranged from 1.4 to 1.5 in co-electrolysis when CO₂/H₂O= 1/1 gas was fed. Performance comparison at 1073 K indicated that direct CO₂ electrolysis occurred, however, steam electrolysis predominately occurred under co-electrolysis conditions. The prepared cell shows good stability at −0.1 A/cm² under CO₂/H₂O co-electrolysis for 200 h, with almost no change in terminal potential with minimal degradation.