ZIF-derived senbei-like Co9S8/CeO2/Co heterostructural nitrogen-doped carbon nanosheets as bifunctional oxygen electrocatalysts for Zn-air batteries

The rational design and construction of the efficient and robust non-noble metal bifunctional oxygen electrocatalysts is of critical significance due to the attention given to reversible metal-air batteries. In this paper, we report novel two-dimensional senbei-like Co9S8/CeO2/Co-NC nitrogen-doped carbon nanosheets (Co9S8/CeO2/Co-NC) derived from a unique 2D Co/Ce bimetallic ZIF. The phase transition from 3D spherical Co-ZIF to 2D Co/Ce-ZIF was achieved through the introduction of Ce ions. Profiting from the successful construction of the unique Co9S8/CeO2 heterostructure and the synergetic effect of two components, the as-prepared Co9S8/CeO2/Co-NC exhibited excellent electro-performance in both the oxygen evolution reaction (E-j=10 = 1.60 V) and oxygen reduction reaction (E-1/2 = 0.875 V). Furthermore, when used as a bifunctional air electrode for Zn-air batteries, Co9S8/CeO2/Co-NC reached a high peak power density of approximate to 164.24 mW cm(-2) at a high current density of approximate to 351 mA cm(-2) and displayed an outstanding cycling stability of more than 668 h at 5 mA cm(-2). This research provides new guidelines for preparing hybrid materials from cobalt-based sulfide species and CeO2 for electrocatalysis and energy storage or other fields.

Automated summary

This study introduces a novel two-dimensional cobalt/cerium bimetallic nanosheet with excellent electrocatalytic performance for oxygen reduction and evolution reactions, as well as a high peak power density and outstanding cycling stability in Zn-air batteries. The research provides new insights for the preparation of hybrid materials for electrocatalysis and energy storage applications from cobalt-based sulfide species and ceria.