The effect of plasma treatment on flexible self-standing supercapacitors composed by carbon nanotubes and multilayer graphene composites

Flexible self-standing supercapacitor devices (FSSS) have attracted great attention in several areas due to their potential use in a wide range of applications, such as roll-up displays, wearable electronics, and storage energy devices. However, the success of FSSS devices is highly dependent on their electrochemical properties. Here, we presented an innovative process for the preparation of novel low-cost ionic gel and superficial CO2 plasma treatment to modify electrodes based on multiwall carbon nanotubes (MWCNT) and multilayer graphene (MLG). The hybrid supercapacitors were characterized morphologically and structurally via scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. To assess the electrochemical properties, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy were used. The morphological results showed that the new CO2 plasma treatment promoted a better distribution of the carbon components, improving the contact area between the electrolyte and the electrode surface. Electrochemical tests demonstrated excellent behavior of the electrolyte gel, with specific capacitances of 256 mF cm(-2) and 603 F g(-1), energy and power densities of 24.03 mu Wh cm(-2) and 2.16 mW cm(-2), respectively. Additionally, the CNT incorporation on the MLG electrodes and the plasma treatment were important factors to produce flexible supercapacitors fashion. The MLG + MWCNT pure and plasma treated appeared as remarkable material for flexible high-performance energy storage devices.

Automated summary

This study presented an innovative method for preparing low-cost ionic gel and superficial CO2 plasma treatment to modify electrodes based on multiwall carbon nanotubes and multilayer graphene, resulting in flexible supercapacitors with excellent electrochemical performance.