Rapidly Enhancing Electrochemical Performance of Perovskite Anode by Extreme Processing.

Abstract

Solid oxide fuel cell (SOFC) is a useful electrochemical device that can directly convert chemical energy into electrical energy. Benefitted from their mixed ionic and electronic conducting property and good stability in a wide oxygen partial pressure (pO₂) window, perovskite oxides are widely applied in SOFCs. However, due to the intrinsically low electrochemical activity, perovskite-based cells usually show inferior output at low temperatures. Herein, it is proposed to engineer both the surface and the bulk of perovskite to improve its electrocatalytic performance. First, it is demonstrated that by progressive extreme processing (extreme plasma ≈5 min + extreme voltage shock ≈50 s), the activity of perovskite anode La_0.35Ca_0.45Ti_0.84Fe_0.08Ni_0.08O_{3- δ} (LCTFN) can be significantly enhanced, primarily attributed to the increased concentration of oxygen vacancy and the improved conductivity after engineering the surface and the bulk of LCTFN, and thus bringing about an enhanced kinetics of hydrogen oxidation reaction. At a relatively low temperature of 700 °C, a favorable peak power density of 1.2 W cm^-2 is obtained for the bulk-engineered LCTFN, which is ≈24 times higher than that of the pristine LCTFN. This study establishes a new method to effectively activate the perovskite oxide in a rapid manner and lower the working temperature of perovskite anode-based SOFCs.