Preparation,Regulation And Multifunctional Application Of Flexible Carbon-Based Conductive Materials

In recent years,carbon-based materials such as graphene,carbon nanotubes,and carbon fibers have been widely used in the field of wearable flexible electronics due to their excellent electrical conductivity,flexibility,light weight,and low cost,which has become potential substitutes for metal materials.Starting from the shielding module of the flexible anti-electromagnetic interference system,the antenna module of the flexible signal transceiver system,and the electrode module of the flexible energy conversion or storage system,this article explores the practical significance of conductive carbon-based materials in the above fields.The specific research is as follows:（1）In this paper,graphene（RGO）synthesized by wet method is used as raw material to prepare flexible graphene conductive film and graphene-based composite conductive film,applying them in the field of electromagnetic shielding.The conductivity and surface roughness of the self-supporting graphene film can be adjusted by changing the temperature,pressure in the thermal reduction process;Aiming at the shortcomings of self-supporting graphene conductive films,such as poor intrinsic conductivity,weaken instability in mechanical properties,and difficulty in large-scale preparation,this paper proposes a simple and green process to prepare large-scale,highly conductive graphene-based films.By introducing CNT@Epoxy,Ag NW nano materials to configure graphene-based conductive ink with good dispersibility to be coated on a flexible PET substrate to form a film.Two-dimensional RGO sheets,one-dimensional CNT and Ag NW can be mutually constructed with a three-dimensional network structure inside the film.This network structure can not only increase the transmission path of electrons,but also its"physical confinement"effect can effectively prevent the self-aggregation phenomenon of the RGO sheet with high surface energy.By tuning the filler ratio of each nano-component in the ink,the surface resistance of the graphene-based composite film can easily be as low as 1.94±0.63Ω/sq;In combination with the promotion of scientific research institutes brought by the interdisciplinary,the corresponding relationship between the electrical properties of the film and the shielding performance is established in advance using CST electromagnetic simulation software,and the desired electrical parameters of the film can be obtained before the material preparation experiment,which made material preparation more goal-oriented.The measured results show that the flexible graphene-based film exhibits an EMI SE performance of no less than 35 d B in the frequency range of 2.6-40 GHz,which is basically consistent with the simulation results.This work provides a technical simplification strategy for the rational design of flexible,large-area EMI shielding film,and expands its application in the field of wearable flexible electromagnetic shielding.（2）The flexible antenna is prepared based on the graphene-based ink optimized in the previous period of this paper,and the structure of the small flexible graphene-based antenna is reasonably designed according to the matching principle between the various parts of the antenna.By adding an ultra-thin smooth PET film on the surface of the fabric,the problem that graphene-based ink is not easy to coat on the surface of the fabric is solved.Subsequently,the radiation performance of the preset flexible antenna was evaluated through HFSS simulation.The simulation results showed that the flexible graphene-based antenna can exhibit a radiation performance of-19.7 d B at an operating frequency of 0.9 GHz.The actual measurement results show that although the antenna has a certain frequency deviation and radiation attenuation,which can still meet the needs of near-field RFID and provide a new strategy for the rational design and preparation of fabric antenna.（3）In this paper,waste cotton fabrics are recycled into flexible electrodes of carbonized cotton fabric and used in the field of flexible energy conversion or storage.Specifically,the waste cotton fabric is carbonized under the protection of inert gas at a high temperature to obtain conductive carbonized cotton that retains the characteristics of the fabric.The sheet resistance of CC-800 carbonized at 800℃can reach 32.9Ω/sq.It still maintains stable resistance even under the bending deformation of curvature,which can be used as the base material of flexible electrode.Aiming at the problem that the carbonized cotton fabric has a relatively smooth fiber surface and poor wettability,which is not conducive to the loading of electrochemically active materials,the surface of the fiber is modified by thermal oxidation.After 300℃thermal oxygen treatment,OXCC-300 with both conductivity and lyophilicity can be obtained.Fe（acac）₃/PVP nanofibers obtained by electrospinning technology are used as iron sources.N-type semiconductorα-Fe₂O₃ crystals are loaded on the surface of carbonized cotton fibers by a simple one-step hydrothermal method to prepare flexibleα-Fe₂O₃@OXCC composite photoanode.The effects of the wettability,conductivity,and crystal loading of the flexible electrode on the photoelectric performance have been specifically studied.The research shows that theα-Fe₂O₃@OXCC-64 flexible electrode can achieve a crystal loading density of 0.66mg/cm² and 0.4 m A/cm².Moreover,the flexible composite photoanode exhibits higher photoelectric performance than theα-Fe₂O₃@FTO electrode with the same crystal mass load density,which becomes a potential material to replace the traditional rigid FTO substrate.