Highly Dispersed Ru-Co Nanoparticles Interfaced With Nitrogen-Doped Carbon Polyhedron for High Efficiency Reversible Li-O 2 Battery.

The lithium-oxygen (Li-O 2 ) battery with high energy density of 3860 Wh kg -1 represents one of the most promising new secondary batteries for future electric vehicles and mobile electronic devices. However, slow oxygen reduction/oxygen evolution (ORR/OER) reaction efficiency and unstable cycling performance restrain the practical applications of the Li-O 2 battery. Herein, Ru-modified nitrogen-doped porous carbon-encapsulated Co nanoparticles (Ru/Co@CoN x -C) are synthesized through reduction of Ru on metal-organic framework (MOFs) pyrolyzed derivatives strategies. Porous carbon polyhedra provide channels for reactive species and stable structure ensures the cyclic stability of the catalyst; abundant Co-N x sites and high specific surface area (353 m 2 g -1 ) provide more catalytically active sites and deposition sites for reaction products. Theoretical calculations further verify that Ru/Co@CoN x -C can regulate the growth of Li 2 O 2 to improve reversibility of Li-O 2 batteries. Li-O 2 batteries with Ru/Co@CoN x -C as cathode catalyst achieve small voltage gaps of 1.08 V, exhibit excellent cycle stability (205 cycles), and deliver high discharge specific capacity (17050 mAh g -1 ). Furthermore, pouch-type Li-O 2 batteries that maintain stable electrochemical performance output even under conditions of bending deformation and corner cutting are successfully assembled. This study demonstrates Ru/Co@CoN x -C catalyst's great application potential in Li-O 2 batteries.