La1−xAgxMnO3 electrocatalyst with high catalytic activity for oxygen reduction reaction in aluminium air batteries

Abstract

The LaMnO₃ (LMO) perovskite catalyst has been proposed as one of the best oxygen reduction reaction catalysts (ORRCs) to substitute noble metals. However, its ORR catalytic activity needs to be further improved. Here, La_1−xAg_xMnO₃ (LAM) perovskites doped with Ag are synthesized by a facile improved sol–gel method. The structures, morphologies and valence states of Mn and oxygen adsorption behaviors of these LAM samples are characterized, and their catalytic activities toward ORR are studied by the rotating ring-disk electrode (RRDE) and aluminum air battery technologies. The results demonstrate that the doping of 30% Ag in the A-site of LMO (LAM-30) can effectively improve its ORR catalytic activity due to the regulation of the manganese valence and improvement of the oxygen adsorption capacity. Besides the remarkable ORR catalytic activity, the LAM-30 catalyst exhibits good durability. The current retention is as high as 98% after the aging test for 10 000 seconds. In addition, the maximum power density of the aluminum air battery using LAM-30 as the ORRC can reach 230.2 mW cm⁻², which indicates that LAM-30 can be used as a promising ORRC in aluminum air batteries.