Nanofiber Cellulose‐Incorporated Nanomesh Graphene–Carbon Nanotube Buckypaper and Ionic Liquid‐Based Solid Polymer Electrolyte for Flexible Supercapacitors

Abstract

Flexible all‐solid‐state supercapacitors are actively investigated for their potential applications in flexible and wearable electronic devices. The important challenge in this field is to achieve a long‐term cycling stability under repeated bending and high energy. Herein, the design and synthesis of the following are reported: 1) nanofiber cellulose (NFC)‐incorporated nanomesh graphene–carbon nanotube (CNT) hybrid buckypaper electrodes with an excellent flexibility and a high specific capacitance and 2) an ionic liquid‐based solid polymer electrolyte with an excellent mechanical flexibility to realize the aims. Herein, the NFC is used to increase the packing density of the buckypaper through the hydrophobic interaction with CNTs, thereby improving the mechanical flexibility. As for the solid polymer electrolyte, the crosslinked structure is induced to provide the pathways for ion conduction and mechanical integrity even at a high ionic liquid content by chemically attaching triethoxysilane end groups to poly(ethylene oxide)‐poly(propylene oxide)‐poly(ethylene oxide) triblock copolymer. The sandwich structure of 1) and 2) exhibits an excellent cycling stability over 5000 bending cycles and high areal energy density (247 μWh cm−2), which are superior to those previously reported in flexible supercapacitors.

Porous Carbon Composite Generated from Silk Fibroins and Graphene for Supercapacitors

“…It has been regarded as an ideal negative electrode for a capacitor cell with a wide operating voltage range. − Carbon materials usually possess low capacitance and insufficient energy density due to their typical electric double-layer capacitor charge-storage mechanism. Most of the studies were devoted to the modification and exploration of hierarchical porous structures for carbon materials. − Active carbons possess highly porous surface areas consisting of different types of pores while having poor electrical conductivity and a relative high series resistance of the electrode [electron series resistance (ESR)] and low power density. Carbon nanotubes (CNTs) are well known for their excellent conductivity and good mechanical properties, but they have limited accessible surface area especially for the tightly bundled CNTs and multiwalled carbon nanotubes.…”

A Nanofibrillated Cellulose-Based Electrothermal Aerogel Constructed with Carbon Nanotubes and Graphene

“…Many studies have shown that NFC can be used as a dispersant to promote dispersion stability of hydrophobic CNTs and rGO in aqueous suspension [ 37 , 38 ]. Meanwhile, NFC can improve the mechanical properties of its composite [ 39 ]. For example, the mechanical strength of a CNFs/rGO film was significantly improved as compared with that of pure rGO film [ 40 ].…”