High-performance La0·3Sr0·7Fe0·9Ti0·1O3-δ as fuel electrode for directly electrolyzing CO2 in solid oxide electrolysis cells

Abstract

Solid oxide electrolysis cell (SOEC) can directly convert CO2 into CO using electric energy, which has important implications for C-mitigation and energy conservation. However, the deficiency of highly active fuel electrode hinders the development of SOECs for CO2 electrolysis. In this work, high-performance La0·3Sr0·7Fe0·9Ti0·1O3-δ (LSFTi 91) material is obtained by decreasing the Ti content in La0·3Sr0·7Fe0·7Ti0·3O3-δ (LSFTi 73). Based on the premise of maintaining stability in CO2 atmosphere, LSFTi 91 exhibits higher conductivity and more oxygen vacancies than LSFTi 73, which not only decreases ohmic resistance introduced by LSFTi 73, but also promotes the charge transfer and further reduces the polarization resistance. Concretely, the Rp of LSFTi 91 electrolytic cell is as low as 0.12 Ω cm2 at 1.5 V, indicating that LSFTi 91 possesses excellent catalytic activity. Furthermore, LSFTi 91 shows higher electrolysis performance than LSFTi 73, and the current densities at 2 V increases from 1.46 A cm−2 to 2.15 A cm−2. Under applied voltage of 1.2 V at 800 °C, LSFTi 91 demonstrates reasonable short-term stability and Faraday efficiency of 91.5%.