Precise Engineering of Octahedron-Induced Subcrystalline CoMoO4 Cathode Catalyst for High-Performance Li-Air Batteries

Lithium-air batteries (LABs) have attracted intense interest due to their ultrahigh energy density. However, the performance of LABs has to depend on modified electrolytes, gas selective film and Li anode protection. In this study, firstly it is reported that Mo-O octahedron induced subcrystalline scheelite CoMoO4 catalyst achieves a high performance LABs performance based only on the high catalytic activity in air. The subcrystalline CoMoO4 catalyst obtains a specific capacity of 12 000 mAh g(-1), and ultralong cycle stability over 270 cycles at 1000 mA g(-1) in ambient air. This study demonstrates an ultrastable crystal structure and surface conditions of the CoMoO4 catalyst toward a corrosive environment and complex air-involved reactions. A theoretical calculation further reveals that the polyhedral framework in the scheelite CoMoO4 can provide a highly stable catalytic surface for the OER/ORR reactions, furthermore, its repulsive nature toward H2O and CO2 can efficiently avoid side reactions and slow the corrosion of the Li anode in air. Moreover, the induced octahedron enhances the adsorption energies to O-2 and LiO2, and accelerates the catalytic reactions in air. The present study provides a conceptual breakthrough to find highly active cathode catalysts for LABs.

Automated summary

A subcrystalline scheelite CoMoO4 catalyst with Mo-O octahedron is utilized in lithium-air batteries (LABs), achieving high performance with a specific capacity of 12,000 mAh g(-1) and ultralong cycle stability over 270 cycles in ambient air. The CoMoO4 catalyst demonstrates an ultrastable crystal structure and surface conditions, providing a highly stable catalytic surface for the oxygen evolution and oxygen reduction reactions. The induced octahedron enhances the adsorption energies to O-2 and LiO2, accelerating the catalytic reactions in air. This study represents a conceptual breakthrough in finding highly active cathode catalysts for LABs.