Steam/CO2 electrolysis in symmetric solid oxide electrolysis cell with barium cerate-carbonate composite electrolyte

Abstract

A composite electrolyte, Zr doped BaCe0.8Y0.2O3-δ (BaCe0.5Zr0.3Y0.2O3-δ, BCZY) and binary carbonates [(Li,Na)2CO3] (LNCO) was first applied to reduce CO2 accompanied with steam electrolysis in solid oxide electrolysis cell (SOEC) at 600°C, lower than which conventional SOEC composed by YSZ works in (usually above 800°C). Electrolysis performances are improved due to sufficient steam feed at oxygen electrode side (30–110ml/min). Steam electrolysis provides proton source for the reduction of CO2. Application of composite electrolyte promotes proton transport and directly leads to H2 even CH4 production. To a certain degree, carbon resistance guarantees the symmetric SOEC operation at a lower bias potential of 0.5V (vs.OCV) applied. A redox-stable and carbon-tolerant LSCM as symmetric electrode with a hybrid-ion-conducting composite electrolyte realizes the fuel synthesis by CO2 reduction in proton-type solid oxide electrolyzer.