3D interconnected porous carbon derived from spontaneous merging of the nano-sized ZIF-8 polyhedrons for high-mass-loading supercapacitor electrodes

Interconnected porous carbons show great potential for high-rate capacitive energy storage, especially at high electrode mass loadings, due to their continuous conductive network and ion migration channels. Herein, we show a simple construction of 3D interconnected porous carbon through spontaneous merging of nano-sized ZIF-8 polyhedrons (ca. 76 nm) during the pyrolysis process. The obtained porous carbon shows a continuous conductive network, interconnected micro-/meso-porous structure, abundant N and O heteroatoms, and good hydrophilicity, enabling fast electron and ion transport kinetics for thick electrodes. As a result of the above merits, the as-obtained carbon shows high capacitance (320.7 F g(-1) at 1 A g(-1)) and outstanding rate performance (213.9 F g(-1) at 100 A g(-1)). Importantly, even at a high mass loading of 15 mg cm(-2), the as-prepared material exhibits an outstanding rate performance of 137.7 F g(-1) at 100 A g(-1). Furthermore, the assembled symmetric supercapacitor using 1 mol L-1 Na2SO4 electrolyte shows a high energy density of 20.6 W h kg(-1) at 0.5 kW kg(-1) and 7.6 W h kg(-1) at 34.3 kW kg(-1), as well as good cycle stability. Our work indicates that building 3D interconnected structure by merging nanoparticles shows great potential for high-mass-loading energy storage.