Application of Large Specific Surface Area Perovskite Oxygen Reduction Catalyst with Three-Dimensional Macropores in Aluminum Air Battery

Abstract

Perovskite-type catalytic materials have received wide attention as high-performance, low-cost alternatives to precious metal catalysts on the market at present. For a typical perovskite oxide (ABO3), the perovskite material with unsubstituted A and B sites is rarely used as an oxygen reduction catalyst alone due to its limited activity. Secondly, due to the high calcination temperature, the perovskite material usually has a small specific surface area. In this paper, the partial substitution of the A site element is carried out to improve the activity and stability of perovskite oxide, combining with the template method to increase the specific surface area of the perovskite La0.7Sr0.3MnO3 (LSMO) material. The physicochemical properties of the synthesized materials were characterized by SEM, EDS, XRD and BET. The catalytic activity of LSMO as an oxygen reduction reaction (ORR) catalyst was measured by a rotating disk test system. After that, the catalyst material was applied to a flexible aluminum air battery and its discharge behavior and flexibility was studied and tested. The results show that LSMO prepared with SiO2 template has a higher specific surface area (61.5486 m2/g) and pore volume (0.267392 cm3/g), and it also shows higher electrocatalytic activity in the electrochemical test system. When it is used in aluminum-air batteries, the activity of 3D porous LSMO is significantly better than that of sheet and bulk LSMO. The aluminum air battery assembled by LSMO prepared by the template method has a higher discharge voltage (up to 1.46 V) at a constant current. In addition, discharged performance degradation of template-based LSMO was obviously slowed down in the large current density, and the discharge voltage can be improved by 8.2% and 24.5%, respectively, compared with the template-free method and sol-gel method. The specific capacity and energy density of the battery were up to 1048.6 mA h/g and 1020.6 mW h/g, respectively. The battery does not damage its inherent structure within a certain range of deformation, and the output voltage is maintained above 1.38 V. Once released, the voltage can be immediately restored to over 99% of the initial value. This design not only provides a new direction for the future development of variable power supplies, but also provides a new solution for powering wearable electronic devices in the future market.