Co3O4/Co nano-heterostructures embedded in N-doped carbon for lithium-O2 batteries

Abstract

Rational design and synthesis of high-performance bifunctional oxygen electrocatalysts with increased effective active sites and facilitated mass/electron transfer are in demand for the lithium-oxygen batteries (LOBs) to overcome the sluggish oxygen reduction/evolution kinetics. Herein, a simple yet effective strategy is proposed by annealing the Prussian blue analog (PBA) precursor under altered calcination conditions to achieve the efficient nano-heterojunction catalysts with optimized active sites. As a result, the obtained porous Co3O4/Co nano-heterostructures embedded in N-doped graphitized carbon matrix (Co3O4/Co@NC) exhibit outstanding electrochemical performance with a high specific capacity of 22,156 mA h g−1 at the current density of 100 mA g−1 and excellent stability, obviously superior to the LOBs based on the other single-component catalysts. Systematic investigations suggest that the enhanced electrochemical performance is ascribed to the Co3O4/Co nano-heterostructure interface and the N-doped porous carbon matrix. This study presents a simple and effective approach for boosting the PBA-derived catalysts with efficient reactivity for various catalytic applications.