Zn, N co-doped carbon with hierarchical pores from cellulose/ZIF composite for electrochemical energy storage

Porous carbons are regarded as potential cathodes for rechargeable electrochemical energy storage. Herein, we propose a simple method to fabricate a bifunctional carbon-based electrocatalyst from carboxymethyl cellulose (CMC)/ZIF-8 composite. In this approach, CMC is selected as a renewable carbon source and support to bind with ZIF-8 and generate abundant mesopores and macropores, while ZIF-8 contributes to a Zn, N co-doped structure and introduces numerous micropores. By optimizing the mass ratio of CMC to ZIF-8, the resulting carbon (CMC@ZnNPC-1.2) reveals hierarchically porous structure enriched with nanopores, which enable efficient electrolyte/gas infiltration and expose more Zn and N doping sites. CMC@ZnNPC-1.2 displays exceptional ORR/OER performances, and the as-assembled Zn–air battery achieves high specific capacity and excellent cycling durability. Additionally, CMC@ZnNPC-1.2 can also be applied as an electrode for supercapacitor. This research offers a feasible approach for producing desirable carbons for electrochemical energy systems.