Abstract

Carbon-based materials are widely being used in supercapacitors as an electrode due to their ease of availability, low cost, and their existence in a variety of forms. Unfortunately, a binder material is commonly employed in the fabrication of electrode materials which leads to additional weight to the electrodes without contributing to electrochemical performance. Here, binder-free, and lightweight electrodes for supercapacitor are fabricated using a simple powder processing of carbon nanofibers (CNFs) and graphene nanoplatelets (GNPs) resulting in a composite material. The morphology and surface area of the electrodes were characterized using SEM and BET techniques. The electrochemical performance of the composite electrodes with varying the contents of GNPs was tested in an aqueous electrolyte using cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy. Under the optimal contents (GNP: CNFs = 90 wt.%: 10 wt.%), the CNFs/GNPs (120 F g⁻¹) composite delivers ~5.2-times and ~3.6-times higher capacitance to CNFs (23 F g⁻¹) and GNPs (33 F g⁻¹) respectively. The power law analysis suggests that the charge storage mechanism is predominately dominated by the surface-driven capacitive components. The decreased ESR values for the composites are correlated with the absence of any binding materials. The minimal charge transfer resistance in the optimized electrode signifies better charge transfer kinetics and is validated by the formation of conducting networks demonstrated by the formation of percolating network. The energy density increased from 2.3 to 6.4 Wh kg⁻¹ at 4 A g⁻¹ and power density from 490 to 1450 W kg⁻¹ at 1.43 A g⁻¹ for the increase of GNP contents from 10-90 wt.% in CNF/GNPs composite. Such binder-free electrodes can be very useful in integrating them in lightweight and flexible energy devices.

Title

allan

Publisher

Nanotechnology

Publisher Country

China

Indexing

Thomson Reuters

Impact Factor

2.9

Publication Type

Prtinted only

Volume

35

Year

2024

Pages

16