Flexible Polyester Cellulose Paper Supercapacitor with a Gel Electrolyte

Abstract

A low-cost polyester cellulose paper has been used as a substrate for a flexible supercapacitor device that contains aqueous carbon nanotube ink as the electrodes and a polyvinyl alcohol (PVA)-based gel as the electrolyte. Gel electrolytes have attracted much interest due to their solvent-holding capacity and good film-forming capability. The electrodes are characterized for their conductivity and morphology. Because of its high conductivity, the conductive paper is studied in supercapacitor applications as active electrodes and as separators after coating with polyvinylidene fluoride. Carbon nanotubes deposited on porous paper are more accessible to ions in the electrolyte than those on flat substrates, which results in higher power density. A simple fabrication process is achieved and paper supercapacitors are tested for their performance in both aqueous and PVA gel electrolytes by using galvanostatic and cyclic voltammetry methods. A high specific capacitance of 270 F g(-1) and an energy density value of 37 W h kg(-1) are achieved for devices with PVA gel electrolytes. Furthermore, this device can maintain excellent specific capacitance even under high currents. This is also confirmed by another counter experiment with aqueous sulfuric acid as the electrolyte. The cycle life, one of the most critical parameters in supercapacitor operations, is found to be excellent (6000 cycles) and less than 0.5 % capacitance loss is observed. Moreover, the supercapacitor device is flexible and even after twisting does not show any cracks or evidence of breakage, and shows almost the same specific capacitance of 267 F g(-1) and energy density of 37 W h kg(-1) . This work suggests that a paper substrate can be a highly scalable and low-cost solution for high-performance supercapacitors.

High-performance supercapacitors based on the carbon nanotubes, graphene and graphite nanoparticles electrodes

“…In another study, the polyester paper supercapacitor has been investigated based on the CNTs electrode and PVA gel electrolyte by Karthika et al. [27]. They reported the specific capacitance of the paper supercapacitor was 276 F g − 1 at 5 mV/s.…”

Graphite nanoparticles paper supercapacitor based on gel electrolyte

“…In Ref. [32], a polyester paper supercapacitor based on the MWCNTs electrode and PVA electrolyte has been reported. At it is shown, the specific capacitance of the paper supercapacitor was 276 F g −1 in scan rate 5 mV s −1 .…”

Nanocellulose‐based polymer composites for energy applications—A review

“…In a similar way, flexible supercapacitors can be prepared by printing, filtration, or coating methods employing various either carbonaceous materials, conductive polymers or metal oxides. [78][79][80] Among these processing methods, conformal coating offers higher strength, flexibility, and mass loading as well. The conformally-coated pyrrole on cationic NC has displayed high normalized volumetric (122F/cm 3 ) and gravimetric (127 F/g) capacitances at 300 mA/cm 2.…”

“…It demonstrated higher capacitance compared with when PET was used as a substrate. In a similar way, flexible supercapacitors can be prepared by printing, filtration, or coating methods employing various either carbonaceous materials, conductive polymers or metal oxides . Among these processing methods, conformal coating offers higher strength, flexibility, and mass loading as well.…”