Preparation And Performance Of Biomass-based Flexible Electrode Materials

Flexible supercapacitor is a kind of energy storage device with a broad application prospect.However,the development of cost-efficient and high-performance flexible supercapacitor electrodes remains a big challenge today.For the preparation of flexible electrode materials with high supercapacitance performance,this dissertation adopted a new train of thought that combined different capacitance storage mechanisms and two kinds of high-performance flexible composite electrode materials were prepared by physical and chemical method,i.e.,cellulose nanofiber/cellulose-derived carbon sheet/polyaniline(CNF/CCS/PANI)and microfibrillated cellulose/chitosan-derived carbon sheer/polyaniline(MCF/CSC/PANI).(1)The sheet-like carbon material(CCS)prepared from cotton]inter was mixed with CNF suspension prepared from hardwood pulp,and then PANI was deposited on their surfaces by the in situ polymerization;finally,after the vacuum filtration and freeze-drying process,flexible supercapacitor electrode materials(CNF/CCS/PANI)with excellent electrochemical performance could be prepared.A relatively low CCS loading can produce a flexible electrode(CNF/CCS/PANI2:2:1)with an ultrahigh specific areal capacitance of 1838.5 mF cm-2(1 mA cm-2).while high CCS loading can produce a free-standing electrode(CNF/CCS/PANI2:4:1)with a higher specific areal capacitance of 3297.2 mF cm-2(1 mA cm-2).And as the current density increases from 1mA cm-2 to 20 nA cm-2,the specific arel capacitance of CNF/CCS/PANI2 21 decrease from 1838.5 mF cm-2 to 860 mF cm-2,indicating a good rate capability.Besides,the robust three-dimensional network guarantees good cycling stability of the nanocomposite electrode(more than 88%retention after 1500 cycles).(2)The sheet-like carbon material(CSC)prepared from chitosan was absorbed onto the flexible MCF aerogel prepared from hardwood pulp,and then PANI was deposited on their surfaces by the in situ polymerization;finally,after the tableting and drying process,foldable and flexible supercapacitor electrode materials(MCF/CSC/PANI)with excellent electrochemical perfornance could be prepared.MCF/CSC/PANI0.5 exhibits an ultrahigh specific capacitance high up to 1688.8 mF cm-2(1 mA cm-2)with a excellent cycling stability(94.8%retention after 1500 cycles).