A Self-activation Strategy to Prepare ZIF-8 Derived N, O Co-doped Meso-microporous Carbon for Zinc Ion Hybrid Capacitors

Abstract

Porous carbon derived from metal-organic frameworks (MOFs) is usually carbonized and then activated by the additional introduction of potassium hydroxide. The use of a large amount of strong alkali during the reactivation process not only corrodes equipment but also pollutes the environment, which is not conducive to large-scale production. Herein, for the first time, we report a novel self-activation strategy of the fabrication of porous carbon derived from zeolitic imidazolate framework-8 (ZIF-8), where the activator ZnCl2 is derived from the pickling step following the initial carbonization of ZIF-8. The optimized porous carbon (ZPC-800) materials show a high specific surface area with an interconnected micro/mesoporous structure and rich nitrogen (17.3 at.%) and oxygen (9.5 at.%) functional groups. As a result, the assembled Zn//ZnSO4(aq)//ZPC-800 hybrid capacitor achieves a high capacity of 165.2 mAh g-1 and impressive energy/power density of 111.2 Wh kg-1/8.0 kW kg-1. This study provides a new prepare method for the preparation of porous carbon materials for zinc ion hybrid capacitors.