Ultralight, High Capacitance, Mechanically Strong Graphene-Cellulose Aerogels.

Xiuya Wang,Pengbo Xie,Ke Wan,Zhenbo Liu,Yuanyuan Miao

doi:10.3390/molecules26164891

Xiuya Wang, Pengbo Xie + Show 3 more

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https://doi.org/10.3390/molecules26164891

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Abstract

With increasing energy demand driving the need for eco-friendly and efficient energy storage technology, supercapacitors are becoming increasingly prevalent in wearable devices because of their portability and stability. The performance of these supercapacitors is highly dependent on the choice of electrode material. The high capacitance and mechanical properties needed for these materials can be achieved by combining graphene’s stable electrical properties with renewable cellulose’s excellent mechanical properties into porous aerogels. In this study, graphene-cellulose hydrogels were prepared by a one-step hydrothermal method, with porous, ultra-light, and mechanically strong graphene-cellulose aerogels then prepared by freeze-drying. These composite aerogels possess excellent mechanical strength and high specific capacitance, capable of bearing about 1095 times the pressure of their own weight. Electrochemical tests show the specific capacitance of these composite aerogels can reach 202 F/g at a scanning rate of 5 mA/cm2. In view of their high surface area and fast charge transport provided by their 3D porous structure, graphene-cellulose aerogels have great potential as sustainable supercapacitor electrodes.

Highlights

Supercapacitors are an increasingly prevalent type of energy storage device, characterized by fast charge/discharge rates, long cycle life, high power density, and wide operating temperature range
Graphene-cellulose hydrogels were prepared by one-step hydrothermal method, and freeze-dried to prepare graphene-cellulose aerogels
The surface morphology, internal composition, mechanical and electrical properties of the composite aerogels were obtained by scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), FTIR, BET, mechanical property test, and electrical property test

Summary

Introduction

Supercapacitors are an increasingly prevalent type of energy storage device, characterized by fast charge/discharge rates, long cycle life, high power density, and wide operating temperature range. They have established applications in numerous fields, including national defense, railways, new energy vehicles, electronics, communications, and aerospace [1,2,3]. Graphene is an ideal electrode material for capacitor because of its large specific surface area, more energy storage per unit mass, fast charge-discharge, and theoretical capacitance of 550 F/g [6,7,8,9]. Agglomeration is the primary technical barrier for the application of graphene materials in supercapacitors

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