3D carbon nanocage networks with multiscale pores for high-rate supercapacitors by flower-like template and in-situ coating

Abstract

3D hierarchical carbon nanocages, a novel carbon-based material, have demonstrated a strong momentum of high rate capability and power density supercapacitors. Herein we report the preparation of 3D carbon nanocage networks by nano coating carbon precursor on flower-like basic magnesium carbonate microspheres combining with in situ MgO template carbonization and KOH treatment. This material features with interconnected 3D network structure, crosslinked carbon nanocages (15–24nm in size and 2.5–3nm in shell thickness), high specific surface area (1470–1927m2g-1), multiscale pores (macro/meso/micropores) and uniform pore size distribution. Resulting from the multiple synergistic effects of these advantages, the 3D carbon nanocage networks present a remarkably excellent electrochemical performance with a large specific capacitance of 380Fg-1 at 1Ag-1 and high rate capability of 82% when increasing the current density up to 50Ag-1 in three-electrode configuration. For HPCNC-700-a symmetrical supercapacitor, the specific capacitance reaches up to 288Fg-1 at 1Ag-1 and still maintains at 256Fg-1 at 10Ag-1 with the capacitance retention of 89%.