Well-dispersed Pt/RuO2-decorated mesoporous N-doped carbon as a hybrid electrocatalyst for Li-O2 batteries.

ABSTRACT

Despite their high energy density, the poor cycling performance of lithium-oxygen (Li-O2) batteries limits their practical application. Therefore, to improve cycling performance, considerable attention has been paid to the development of an efficient electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Catalysts that can more effectively reduce the overpotential and improve the cycling performance for the OER during charging are of particular interest. In this study, porous carbon derived from protein-based tofu was investigated as a catalyst support for the oxygen electrode (O2-electrode) of Li-O2 batteries, wherein ORR and OER occur. The porous carbon was synthesized using carbonization and KOH activation, and RuO2 and Pt electrocatalysts were introduced to improve the electrical conductivity and catalytic performance. The well-dispersed Pt/RuO2 electrocatalysts on the porous N-doped carbon support (Pt/RuO2@ACT) showed excellent ORR and OER catalytic activity. When incorporated into a Li-O2 battery, the Pt/RuO2@ACT O2-electrode exhibited a high specific discharge capacity (5724.1 mA h g-1 at 100 mA g-1), a low discharge-charge voltage gap (0.64 V at 2000 mA h g-1), and excellent cycling stability (43 cycles with a limit capacity of 1000 mA h g-1). We believe that the excellent performance of the Pt/RuO2@ACT electrocatalyst is promising for accelerating the commercialization of Li-O2 batteries.