Promoting Electrocatalytic Activity and Stability via Er_0.4Bi_1.6O_3−δ In Situ Decorated La_0.8Sr_0.2MnO_3−δ Oxygen Electrode in Reversible Solid Oxide Cell

Abstract

Weak electrocatalytic activity of the La_0.8Sr_0.2MnO_3-δ (LSM) oxygen electrode at medium and low temperatures leads to decreasing performance both in the solid oxide fuel cell (SOFC) mode and the solid oxide electrolysis cell (SOEC) mode. Herein, we design an Er_0.4Bi_1.6O_3-δ (ESB) functionalized La_0.8Sr_0.2MnO_3-δ (labeled as LSM/ESB) oxygen electrode via a one-step co-synthesis modified Pechini method. The unique LSM/ESB with polarization resistance of only 0.029 Ω·cm² at 750 °C enables a highly enhanced rate of oxygen reduction and evolution reaction. The single cell with the LSM/ESB electrode achieves a maximum power density of 1.747 W cm^-2 at 750 °C, 2.6 times higher than that of the mechanically mixed LSM-ESB electrode (0.667 W cm^-2). In the SOEC mode, it also shows the improved performance of the LSM/ESB electrode. Furthermore, the cell exhibits admirable durability of 90 h in the fuel cell mode and excellent reversibility. The better performance can be concluded as a better surface-active state and a tighter connection between the LSM and ESB particles of LSM/ESB via a co-synthesis process. This work proposes a novel strategy to advance the application of the one-step modified Pechini technology for an efficient and stable oxygen electrode.