MXene-supported Ni–Co bimetallic MOF 2D lamellar membrane for enhanced electrochemical oxygen reactions and Li–O2 battery

Abstract Lithium-oxygen (Li-O2) battery is a revolutionary high-performance battery technology due to its exceptionally high theoretical energy density, but challenges associated with the cathode material have hindered its further advancement. Here, an in-situ synthesis strategy was adopted to load a bimetallic Ni-Co metal-organic framework (MOF) onto MXene (Ti3C2) layer, and subsequently prepared a free-standing and flexible Ni/Co-MOF@Ti3C2 hybrid membrane through a layer-by-layer self-assembly method for efficient oxygen reduction reactions (ORR) and as a cathode for Li-O2 batteries. The Ni/Co-MOF@Ti3C2 hybrid membrane integrates the high conductivity and unique two-dimensional layered structure of MXene with the bimetallic active sites of Ni-Co MOF, exhibiting remarkable ORR catalytic activity. The structural characteristics of Ni/Co-MOF@Ti3C2 hybrid membrane provide smoother expansion pathways for Li+ or O2, effectively promoting the deposition and decomposition of Li2O2, thereby overcoming the inherent limitations of traditional slurry-based cathode preparation methods for Li-O2 batteries. Experimental results indicate that Li-O2 batteries utilizing the Ni/Co-MOF@Ti3C2 hybrid membrane as the cathode achieve an ultra-high capacity of 36125 mAh/g at a current density of 1000 mA/g, while demonstrating excellent cycle stability and outstanding rate performance. The promising results offers novel insights into the innovative design of air cathodes for metal-air batteries.