Research On The Preparation And Application Of Bacterial Cellulose-based Conductive Materials

Flexible conductive materials are widely used in the field of electrochemistry.Currently,In order to solve the problem of low conductivity of cellulose-based flexible conductive materials,nanoscale materials are used to increase the specific surface area of the material.Bacterial cellulose(BC)has three-dimensional and nano-scale porous structure.BC presents the attractive features including high specific surface area,high crystallinity and good mechanical properties.It is widely available and inexpensive.Due to these properties,BC has been an excellent template to synthesize conductive composites.Polypyrrole(PPy)is one of most potential conducting polymer for its high electrical conductivity,reversible redox properties and easy synthesis.Carbon nanotubes(CNTs)exhibit high electrical conductivity,good mechanical strength and large specific surface area.It can enhancing the energy conversion and storage performance of conductive materials.In this paper,BC slurry was used as a template to prepare conductive materials by oxidizing and polymerizing of pyrrole and doping with CNTs.The main research contents and results were as follows:(1)BC@PPy conductive paste with a core-shell structure was obtained by beating the bacterial cellulose into a fiber slurry and chemically oxidizing polypyrrole.The preparation conditions of BC@PPy were optimized by a series of single factor tests and response surface tests.According to the response surface test,the conductivity can be optimized when the content of pyrrole monomer is 0.33 mL,the molar ratio of oxidant FeCl3 to pyrrole is 1.3,the molar ratio of hydrochloric acid to pyrrole is 25 and the reaction time is 180 min.(2)Bacterial cellulose @ polypyrrole-single-walled carbon nanotube(BC@PPy-SWCNTs)conductive film was obtained after adding a single-walled carbon nanotube dispersion into BC@PPy conductive paste.The structural morphology was characterized by scanning electron microscope(SEM),Fourier infrared spectroscopy(FTIR)and Raman spectroscopy.Then apply the film into symmetrical supercapacitors.The experiments show that the conductivity of BC@PPy-SWCNTs film can reach 7.379 S·cm-1,and the maximum area specific capacitance of the obtained supercapacitor was 0.605 F·cm-2.At the current density of 1 mA·cm-2,the energy density was 0.0392 mWh·cm-2 and the power density was 0.342 mW·cm-2.(3)A multi-walled carbon nanotube dispersion was added to BC@PPy conductive paste,and bacterial cellulose @ polypyrrole-multi walled carbon nanotube(BC@PPy-MWCNTs)conductive film was prepared.The structural morphology was characterized by SEM,FTIR and Raman spectroscopy.Then apply the film into symmetrical supercapacitors.The experimental results show that the conductivity of BC@PPy-MWCNTs film was 1.595 S·cm-1,and the maximum area ratio capacitance can reach 0.565 F·cm-2.At the current density of 3 mA·cm-2,the power density was 1.020 mW·cm-2,the energy density can reach 0.0363 mWh·cm-2.The above results show that the synergistic effect of polypyrrole and carbon nanotubes can effectively improve the conductivity and electrochemical properties of bacterial cellulose.This study broadens the idea for the development and application of bacterial cellulose-based conductive materials in supercapacitors.