Nitrogen, boron and fluorine tri-doped carbon nanotubes on carbon cloth as the electrode materials for supercapacitors

Abstract

In this study, nitrogen, boron, and fluorine co-doped carbon nanotubes (NBF-CNT) was growth on carbon cloth (CC) through a simple in situ method. The material was used directly as electrodes for supercapacitors and tested for its electrochemical performance. The electrode exhibited an area specific capacitance of 4303.2 mF/cm2 (322.7F/g) at 2 mA/cm2 (0.15 A/g), maintaining 77.4% capacity at 20 mA/cm2. At 10 mA/cm2, the flexible electrode retained 97.8% capacitance after 8000 charge/discharge cycles. Assembled into a symmetrical supercapacitor, the electrodes achieved an area specific capacity of 750.8 mF/cm2 (56.3F/g) at 2 mA/cm2 (0.15 A/g), with energy densities of 104.3 μWh/cm2 (7.8 Wh/kg) and 61.4 μWh/cm2 (4.6 Wh/kg) at power densities of 1000 μW/cm2 (75 W/kg) and 10,000 μW/cm2 (750 W/kg), respectively. The excellent electrochemical performance attibutes two factors: (1) binder-free electrode preparation, mitigating issues related to poor conductivity and low active substance utilization; and (2) the synergistic effect of multi-heteroatom doping in carbon nanotubes, enhancing electrode conductivity and hydrophilicity.