Electrode Materials for Supercapacitors: A Review of Recent Advances

Abstract

The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-active small molecules and bio-derived functional groups displayed a significant effect on the electrochemical properties of electrode materials. These advanced properties provide a vast range of potential for the electrode materials to be utilized in different applications such as in wearable/portable/electronic devices such as all-solid-state supercapacitors, transparent/flexible supercapacitors, and asymmetric hybrid supercapacitors.

A Review of Supercapacitors: Materials Design, Modification, and Applications

“…Furthermore, SCs also offer increased stability and protection of the system, light weight, low heating, and versatility [16]. A Ragone plot comparing several energy storage devices, e.g., conventional capacitors, batteries, fuel cells, and hybrid supercapacitors (HSCs) in terms of power density and energy density [17,18], is shown in Figure 1. HSCs present a considerable power density resembling that of fuel cells and batteries, but substantially lower than typical capacitors.…”

Enhancement of Volumetric Capacitance of Binder-Free Single-Walled Carbon Nanotube Film via Fluorination

“…The CV curves recorded for the non-fluorinated SW and SW_DC electrodes at a scan rate of 100 mV s −1 show a nearly rectangular shape characteristic for EDLCs (inserts in Figure 4 a,b). The CV loops slightly increase with long-term cycling owing to the impregnation of electrodes with 1M H 2 SO 4 electrolyte [ 42 ]. This process is more substantial for the SW film and it is accompanied by the specific capacitance growth by 20% during the long-term cycling ( Figure 4 a).…”

Computational Study of Graphene–Polypyrrole Composite Electrical Conductivity

“…From the modeling results, the effects of filler diameter and matrix thickness has been shown to have varying impact in the tunneling resistance of the composite. For example, a low equivalent resistance is required to obtain a high conductive and high capacitive supercapacitor [ 54 ]. Therefore, a supercapacitor-based polymer-composite must be manufactured with filler having large diameter, and small matrix thickness.…”