Preparation And Characterization Of Biomass-based Flexible Substrate And Carbonized Electrode Materials

The use of biomass materials and biomass industrial and agricultural residues to prepare flexible electronic substrate materials and supercapacitor carbon electrode materials is of great significance to promote the sustainable development of social economy and protect the ecological environment.In this paper,different concentrations of cellulose nanofibers(CNFs)and polyvinylpyrrolidone(PVP)were coated on ordinary cellulose fiber paper in order,and the effects of both on paper structure,transparency and other properties were studied.Carbonized acid residues of corn cob were carbonized under inert gas and activated with KOH to prepare carbon materials.A small amount of nickel cobaltate was loaded on the surface of the carbon material by in-situ synthesis of cobalt-based MOF,and then the electrochemical performance of the prepared carbon(composite)material was studied.Nitrogen-doped carbon materials were prepared using melamine as a nitrogen source and corncob acid hydrolysis residue as a carbon source.Nitrogen-doped carbon materials are loaded with nickel cobaltate on the surface of the materials through KOH activation and in-situ synthesis of MOFs to improve the electrochemical performance of nitrogen-doped carbon materials.Finally,the use of protein-rich lees as raw material,directly carbonized to prepare nitrogen-doped carbon materials.And the use of different concentrations of sodium periodate to oxidize the distillers grains and then carbonize,to improve the chemical properties of carbonized distillers grains.among them:When cellulose nanofibers and polyvinylpyrrolidone are used to coat cellulose fiber paper in sequence,the former can reduce the pore size of the cellulose fiber network,which helps the latter to fill the pores of the fiber network and further greatly improve the paper transparency.When the coating amount of CNFs is 3.93g/m~2 and the coating amount of PVP is 188.7g/m~2.The transmittance of the paper at 550 nm is close to 86%.The transparent paper made by this method shows high thermal stability,high tensile strength,high form stability and flexibility.When the corncob acid hydrolysis residue is used as a carbon source to prepare a carbon material by carbonization,a carbon material with a small specific surface area and a high degree of graphitization can be obtained.The use of KOH activation and in-situ synthesis of cobalt-based MOFs loaded with a small amount of nickel cobaltate can greatly.CCKA-MOFs activated by the two methods combined with KOH activated and loaded with a small amount of nickel cobaltate can have a specific capacitance of204.6 F/g at a constant current charge-discharge current density of 1A/g.And after cycling 5000 times under this current density,the capacitance value of the material still maintained 85.8%of the initial capacitance value.When melamine and corncob acid hydrolysis residue are carbonized together to prepare a nitrogen-doped carbon material,direct carbonization results in a nitrogen-doped carbon material with a small specific surface area and a high degree of graphitization.The carbon material has a specific capacitance of up to 136.6F/g at a current density of 1A/g.The composite carbon material N-CCKA-MOFs prepared by KOH activation and in-situ synthesis of cobalt-based MOFs loaded with a small amount of nickel cobaltate has a capacitance of up to 213.4F/g at a constant current charge and discharge current density of 1A/g.After cycling 5000 times at this current density,the capacitance value of the material still maintained 91.4%of the initial capacitance value.It shows that the material has stable physical and chemical properties and is a potential electrode material for electrochemical capacitors.When carbonization of lees is used to prepare nitrogen-doped carbon materials,the use of sodium periodate to oxidize lees before carbonization can not only save the KOH activation process,but also greatly increase the specific capacitance of the carbon material.When the periodate concentration is 10%,the carbon material obtained by oxidizing distillers grains has a capacitance of 189.4F/g when the current density is 0.5A/g.After 5000 cycles at this current density,the capacitance value of the material still maintained 88.3%of the initial capacitance value.It shows that the physical and chemical properties of the material are very stable.