Recycle and Reuse: Fabrication of carbon microtube derived from waste cardboard for solid-state supercapacitor device

Abstract

Background

The unending consumption of depleting fossil fuels has paved the way for renewable and circular technologies, and enormous effort has been put into garbage management to use them as carbon precursors.

Methods

This study reports the first-ever supercapacitive behavior of carbon microtubes synthesized from a well-known waste material, packaging cardboard, through thermal conversion, which has been introduced as electrode material without any chemical treatment as a green energy storage device.

Significant findings

FESEM and TEM imagining show the carbon microtube structure. The pore architectures, surface area, and chemical characteristics have been easily modified by adjusting the activation temperature. The thermal stability of the carbon microtube was tested by TGA analysis. Upon increasing the carbonization temperature from 400 °C to 900 °C, the specific surface area of the carbon material increased, whereas the contents of nitrogen and oxygen decreased notably, significantly impacting the electrochemical properties of the carbon-based supercapacitors. Excellent charge transfer characteristics of the thermally activated carbon microtube have been studied through EIS and CV analysis. The CV investigations show the electric double-layer capacitor (EDLC) for the 900CB electrode. Galvanostatic charge-discharge (GCD) calculations give a specific capacitance of 127 F g⁻¹ at 1 A g⁻¹. The constructed asymmetric solid-state capacitor shows an outstanding stability of 85% for 10,000 cycles at a current density of 1 A g^−1, unveiling a phenomenal power density of 125 W kg⁻¹ and an energy density of 36 Wh kg⁻¹.