Bioinspired Synthesis of Hierarchically Porous MoO₂/Mo₂C Nanocrystal Decorated N‑Doped Carbon\nFoam for Lithium–Oxygen Batteries

Abstract

The lithium oxygen\n(Li–O₂) battery is one of\nthe most promising technologies among various electrochemical energy\nstorage systems. The challenge to develop a high-performance Li–O₂ battery lies in exploring an air electrode with optimal porous\nstructure and high efficient bifunctional electrocatalyst. The present\nwork demonstrates a bioinspired synthesis route for the preparation\nof high performance Li–O₂ air electrode materials\nthat are made out of N-doped carbon foams decorated with heteronanostructured\nMoO₂/Mo₂C nanocrystals (MoO₂/Mo₂C@3D NCF). Here, recombinant proteins (ELK16-FLAG) facilitated\nthe self-assembly of metal precursors and provided a carbon source\nfor Mo₂C formation. The as-prepared MoO₂/Mo₂C@3D NCF showed superior electrocatalytic activity in both\noxygen evolution reaction and oxygen reduction reaction mechanisms\nwith a high round-trip efficiency of 89.1% (2.77 V/3.11 V) at 100\nmA g^–1 as well as exceptional rate performances\nand good cyclability in Li–O₂ battery. The desirable\nelectrochemical performance can be attributed to the unique hierarchical\nporous structure of the 3D carbon foam and the intimate contact between\nMoO₂ and Mo₂C nanocrystals. We demonstrate that\nthe novel, facile, environmentally friendly bioinspired approaches\nwould open new avenues for the synthesis of 3D nitrogen doped carbon\nsupported advanced functional materials with excellent electrochemical\nperformances.