Preparation Of Conductive Flexible-transparent Film And Electrode Material With Wood Cellulose Nanofibers As Matrix

In this research, waste wood powder was used as raw material to fabricate with high length to diameter ratio and high crystallinity of cellulose nanowhisker(CNW) and cellulose nanofiber(CNF),by the methods of acid hydrolysis and ultrasonification. This research demonstrated that CNW and CNF have an great potential applied in the fields of eco-friendly, flexible, transparent, conductive films and Biological carbon composite electrode materials. In the former field, the CNW and grapheme are assembled layer by layer to obtained multiply membranes composite then the structure, thermodynamic property, transparent property, conductive property of the composite were characterized. In the latter field, CNF as the carbon resource, while manganese acetate was used as the manganese resource, a 3D, high porous composite aerogel was obtained by freeze drying and high-temperature pyrolysis. Subsequently, the electrochemical property and structure of the aerogel were analysis. Conclusions are as follows:(1) CNW as the substrate which can overcome the freestanding of grapheme. we obtained a transparent, conductive, flexible, foldable, high modulus and thermostability composite films. The fabrication of the composite films based on a simple vacuum-filtration is simple, operable.With the amount of CNW and grapheme, the thickness, transmission of light, conductivity of the composite films can be adjusted. The transmission of light and resistance decreases, the conductivity increased while the addition of the grapheme. When the layer of the grapheme is three, the composite film has moderate conductivity(2.8 S/cm), light transmittance performance(53%), Young modulus(10.2 GPa), work of fracture (472.2 KJ/m2),favourable thermostability(under 280℃).(2) The mixture of CNF and manganese acetate solution is homogeneous while the addition of manganese dioxide powder cannot disperse well and aggregate easily.The MnOx/CNF aerogel obtained by freeze drying and high-temperature pyrolysis exhibit a 3-dimensional structure. The porosity of it can be adjusted by the concentrate of the mixture solution. High specific surface area and abundant pores provide the channel to electrolyte, makes the contact area of MnOx and the wettability increasing, the diffusion path of the electrolyte decreasing and the charge transfer impedance and the Warburg impedance reducing, thus achieve the goal of improve integrated capacitive performance. With the addition of the MnOx, the specific capacitance of the composite increased uniformly. When the amount of the manganese source is 40%, MnOx/CNF-4 shows the excellent comprehensive electrochemical properties, the specific capacitance (specific capacitance as high as 138.4 Fg-1 at 2 mVs-1) and rate capability is higher than others. The capacitance of composite material dampings 10% of the initial capacitance after 200 cycles and dampings 17% of the initial capacitance after 500 cycles of chatging/dischaiging at 1 Ag-1.With the increase of cycling times, reducing rate of specific capacitance slowls, showing the electrode material has good cycle stability.