Preparation And Electrical/thermal Behavior Characterization Of Graphene-based Films

Graphene-based membranes are composite materials that combine the superior properties of graphene with those of other materials.These membranes possess high electrical conductivity,thermal conductivity,and surface area,making them significant materials in high-performance fields such as electromagnetic shielding and electric heating.However,graphene-based membranes still face some issues in areas such as electromagnetic shielding effectiveness（Shielding Efficiency,SE）and its relationship with membrane thickness,the impact of interfacial electrical behavior on electromagnetic shielding effectiveness and electric heating performance,the stability and response speed of electric heating performance,energy consumption,and preparation cost.Therefore,this paper studies the macroscopic preparation methods of Graphite Oxide（GO）,Reduced Graphite Oxide（RGO）,RGO/Manganese Ferrite（Mn Fe2O4）,and RGO/Nanocrystalline cellulose（NCC）composite films,and their applications in the fields of electromagnetic shielding,microwave absorption,and electric heating,while decoupling contact interface resistance.The main work is as follows:（1）The electromagnetic shielding performance of RGO and RGO/Mn Fe2O4composite membranes was investigated.The results demonstrate that for RGO membranes with a thickness ranging from approximately 0.1 to 0.8 mm,the SE value in the X-band is about 16-64 d B.RGO/Mn Fe2O4 membranes possess an SE value of 29 d B when subjected to a hot reduction temperature of 800℃.Furthermore,RGO/Mn Fe₂O₄membranes exhibit excellent absorption performance,with a reflection loss value（RL）of 43.2 d B at 14.1 GHz,a thickness of 3 mm,and an effective absorption bandwidth（EAB）of 10.5-16.2 GHz.（2）The contact interface electrical behavior of RGO,RGO/Mn Fe2O4,and RGO/NCC composite membranes was decoupled,and an equivalent circuit for decoupling the graphene-based membrane conductive behavior was established.Based on the equivalent circuit model,the resistance and conductivity of the graphene body and contact interface can be decoupled.By decoupling the contact resistance,the interference of the interface resistance and external conditions（such as pressure,temperature,and corrosion）can be excluded,reducing errors and providing valuable data for obtaining effective experimental results and conclusions.（3）The electrical and thermal behaviors of RGO film,RGO/Mn Fe2O4 composite film,and RGO/NCC composite film were provided.Under a current of 1 A,the RGO film reached a stable temperature of about 74.8℃within 15 s.The RGO/Mn Fe₂O₄ film could reach a saturation temperature of 100.2℃within 15 s under a current of 0.35 A.When it reached the stable temperature,itsΔR/R₀ value decreased by about 65%.In addition,the RGO/Mn Fe2O4 film also had a rapid de-icing response（its maximum de-icing rate under a 0.35 A DC current was about 0.032 g/s）.Compared with the RGO film,the RGO/Mn Fe₂O₄ film had faster heating performance（heating rate of 5.01℃/s）.The prepared RGO/NCC film also had fast electrical heating performance,and it could reach a high saturation temperature of 153℃in about 18 s under a current of 0.125 A（heating rate of 7.11℃/s）.Compared with the previous two,the RGO/NCC film had a higher saturation temperature and smaller energy consumption.At the same time,the RGO/NCC film also had good electrical resistance temperature sensitivity and could be used as a temperature sensing material.Overall,this study has significant scientific implications for the development and preparation of high-performance graphene-based macroscopic membrane materials.It can provide valuable material selection,preparation methods,and data references for the application of graphene-based macroscopic materials in electromagnetic shielding,microwave absorption,electric heating,and temperature sensing.Future research can further explore the continuous and controllable preparation of graphene-based macroscopic membranes,structural optimization and composite,and the construction of an effective structural network to achieve optimal three-dimensional space filling,improve its electrical and dielectric properties,and its applications in electromagnetic shielding,microwave absorption,electric heating,thermoelectricity,and sensing fields.