Cohesive Porous Co₃O₄/C Composite Derived from Zeolitic Imidazole Framework-67 (ZIF-67) Single-Source Precursor as Supercapacitor Electrode

Composite materials containing metal oxide and carbon with optimized structures have shown potential advantages in improving the supercapacitor performance. Herein, the cohesive porous Co 3 O 4 /C composites are synthesized via a two-step calcination of zeolitic imidazole framework-67 (ZIF-67) single-source precursor. The results indicate that Co 3 O 4 nanopaticles are in situ incorporated with partial graphitized carbon. As supercapacitor electrode material, the Co 3 O 4 /C composite exhibit higher specific capacitance (875.6 F g −1 at 1 A g −1 ) and better cycling stability (capacitance retention of 87.8% after 1000 cycles at 6 A g −1 ) compared to pure Co 3 O 4 (245.3 F g −1 and 78.4% at the same condition). In addition, it shows good cycling stability with capacitance retention of 82% after 1000 cycles at 6 A g −1 in the symmetric supercapacitor device. The better electrochemical performance can be attributed to the improvement of the conductivity, larger surface area for more active sites, and the ameliorative volume expansion of Co 3 O 4 by the stable structure of Co 3 O 4 nanopaticles well embedded in partial graphitized carbon matrix during long cycling process.