Cobalt Oxide Nanoparticles Embedded in N-Doped Porous Carbon as an Efficient Electrode for Supercapacitor

摘要

Herein, a sequential pyrolysis and oxidation strategy is developed to prepare Co3O4 nanoparticles embedded in N-doped porous carbon (Co3O4@N-pC) using a bimetal zeolitic imidazolate framework (ZIF-67@ZIF-8) as precursors, which is first obtained via a simple wet-chemical process. The electrochemical performances of Co3O4@N-pC, ZIF-67@ZIF-8 precursors, and Co@N-Pc intermediates (the direct pyrolysis products from ZIF-67@ZIF-8) are studied as supercapacitor electrodes in comparison. The results reveal that the specific capacitance of the optimized Co3O4@N-pC electrode can reach up to 422.8 F g(-1) at 1 A g(-1) with a good rate capability (256 F g(-1) at 5 A g(-1)) and excellent long-term cycling stability (87.9% retention after 5000 cycles). Such performance is superior over ZIF-67@ZIF-8 precursors (232 F g(-1) at 1 A g(-1), 168.9 F g(-1) at 5 A g(-1), and 82.7% retained after 5000 cycles) and Co@N-pC intermediates (218.4 F g(-1) at 1 A g(-1), 171 F g(-1) at 5 A g(-1), and 76.3% retained after 5000 cycles). The findings in this work are expected to provide a new avenue to explore other metal oxide/carbon materials for various applications.