Hierarchical flaky porous carbon derived from waste polyimide film for high‐performance aqueous supercapacitor electrodes

Abstract

The development of electric vehicles is increasing the demand for supercapacitors, for which carbon materials can make excellent electrodes. In this study, waste scraps of polyimide (PI) film were used to fabricate several flaky porous carbon materials for use as supercapacitor electrodes. The pore structure and functional groups of the porous carbons were tailored by KOH activation. The relationships between pore structure, the carbon matrix, functional groups, and electrochemical performance were investigated via N 2 adsorption, XRD, Raman spectroscopy, FT-IR, XPS, and electrochemical measurements.The flaky porous carbon materials have a graded distribution of hierarchical pore structures and are rich in O/N functional groups. They have an outstanding capacitance retention rate and a high specific capacitance of 482 F g À1 , which is higher than those of PI film-based porous carbons prepared by physical activation and of commercial activated carbon electrodes. Their flaky structure endows them with lower impedance than commercial AC. The materials were used to fabricate electrodes for symmetrical supercapacitors, which displayed high energy densities and excellent cycling stability. This work provides an environmentally benign strategy for the re-use of waste PI film.

Polyacrylonitrile-Derived N-Doped Nanoporous Carbon Fibers for CO2 Adsorption

“…To confirm this, its phase structure was characterized by powder X-ray diffraction (XRD), as shown in Figure f. It has been seen that this porous carbon fiber presents two typical broad peaks located at 2θ values of 24 and 43°, which were assigned to C(002) and C(100) diffraction planes of amorphous carbons, respectively …”

“…It has been seen that this porous carbon fiber presents two typical broad peaks located at 2θ values of 24 and 43°, which were assigned to C(002) and C(100) diffraction planes of amorphous carbons, respectively. 44 From the elemental analysis results, this series of nanoporous carbon fiber samples have nitrogen contents ranging from 14.36 to 2.92 wt %, as shown in Table 1. The N content of the as-prepared materials decreased as the activating temperature and KOH/PF mass ratio was increased.…”

The synthesis of Ni/Mn hexacyanoferrate microcubes and nanorods for high‐performance asymmetric supercapacitor in neutral electrolyte

“…Electrodes for supercapacitor can be classified as capacitive‐type electrodes and battery‐type electrodes. For capacitive‐type electrodes, which are usually based on carbon materials, the charges are stored in the double layer at the electrode/electrolyte interface 3 . For battery‐type electrodes, the energy storage is attributed to the charge transfer during the redox reaction of the electrode materials.…”

“…For capacitive-type electrodes, which are usually based on carbon materials, the charges are stored in the double layer at the electrode/electrolyte interface. 3 For batterytype electrodes, the energy storage is attributed to the charge transfer during the redox reaction of the electrode materials. In comparison to capacitive-type electrodes, battery-type electrodes exhibit much higher specific capacity but suffer shorter cycling life.…”

Discarded Polyimide Film-Derived Hierarchical Porous Carbon Boosting the Energy Density of Supercapacitors in Na2SO4 and Spiro-(1,1′)-bipyrrolidinium Tetrafluoroborate Electrolytes

“…In our previous work, we have demonstrated that the discarded polyimide (PI) film, which came from the processing of flexible printed circuit, is an excellent precursor for electrode materials . Herein, the architecture and surface properties of the porous carbon derived from PI films was designed with the micropores concentrated at 0.7–1 nm and wide micro–mesopore distribution to better match with Na 2 SO 4 and SBPBF 4 electrolytes for enhancing the energy density.…”