3D Carbon Frameworks for Ultrafast Charge/Discharge Rate Supercapacitors with High Energy-Power Density

Abstract

3D carbon frameworks (3DCFs) constructed by interconnected nanocages show a high specific surface area, hierarchical porosity, and conductive network.The deoxidization process removed most of surface oxygen-containing groups in 3DCFs that leads to fast ion diffusion kinetics, good electric conductivity, and limited side reactions.The deoxidized 3DCFs exhibit an ultrafast charge/discharge rate as electrodes for SCs with high energy-power density in both aqueous and ionic liquids electrolytes. Carbon-based electric double layer capacitors (EDLCs) hold tremendous potentials due to their high-power performance and excellent cycle stability. However, the practical use of EDLCs is limited by the low energy density in aqueous electrolyte and sluggish diffusion kinetics in organic or/and ionic liquids electrolyte. Herein, 3D carbon frameworks (3DCFs) constructed by interconnected nanocages (10–20 nm) with an ultrathin wall of ca. 2 nm have been fabricated, which possess high specific surface area, hierarchical porosity and good conductive network. After deoxidization, the deoxidized 3DCF (3DCF-DO) exhibits a record low IR drop of 0.064 V at 100 A g−1 and ultrafast charge/discharge rate up to 10 V s−1. The related device can be charged up to 77.4% of its maximum capacitance in 0.65 s at 100 A g−1 in 6 M KOH. It has been found that the 3DCF-DO has a great affinity to EMIMBF4, resulting in a high specific capacitance of 174 F g−1 at 1 A g−1, and a high energy density of 34 Wh kg−1 at an ultrahigh power density of 150 kW kg−1 at 4 V after a fast charge in 1.11 s. This work provides a facile fabrication of novel 3D carbon frameworks for supercapacitors with ultrafast charge/discharge rate and high energy-power density.[Figure not available: see fulltext.]