Boosting oxygen evolution reaction of La0.8Sr0.2MnO3 electrodes by modulating the conductive mechanism with Co element in SOEC

Concentrations of oxygen-vacancy are increased by Co doping in LSM. • Conductive behavior evolution is induced by Co from electronic conductor to MIEC. • Oxygen exchange and charge-transfer processes are synergistically accelerated. • A current density of −0.37 A cm -2 is achieved in an electrolyte-supported SOEC. La 0.8 Sr 0.2 MnO 3 (LSM) oxygen electrodes show sluggish oxygen evolution reaction (OER) kinetics for the limited reaction zones at triple-phase boundaries (TPBs) caused by the pure electronic conductor of LSM. Modulating the conduction mechanism of LSM by Co-doping is one effective by tailoring the physicochemical properties. Effects of Co doping on oxygen-vacancy formation, conduction behavior and electrochemical kinetics are systematically investigated. Co doping increases the oxygen-vacancy concentration and promotes the evolution of conduction mechanism, thereby enhancing oxygen surface exchange and charge-transfer kinetics. DFT calculations further demonstrate that the reduced oxygen-vacancy formation energy and electronic-structure modulation induced by Co doping drive the conduction-mechanism evolution. La 0.8 Sr 0.2 Co 0.2 Mn 0.8 O 3 based single cell delivers a current density of -0.37 A·cm -2 at 1.6 V, representing a 105% enhancement compared to that with pure LSM. This work opens up new avenues improving OER activity of oxides for other applications through rational design of conductive mechanism. Download: Download high-res image (207KB) Download: Download full-size image