Research On Thermoelectric And Sensing Properties Of Three-dimensional Graphene Aerogel And Its Composites

Thermoelectric material is a new type of energy functional material that realizes direct conversion of heat and electric energy by driving carrier directional movement through energy difference.It has many advantages that are incomparable to traditional energy production and utilization methods,so it is widely used in thermoelectric power generation and temperature-sensitive information transmission.At present,the research of thermoelectric materials has made great progress,but the following problems still exist:the existing thermoelectric materials have low ZT values and low thermoelectric conversion efficiency.Since thermoelectric materials have various excellent properties,they can be used as conversion elements for excellent temperature sensors.Thermoelectric temperature sensors usually have the following advantages:a wide measuring temperature range,and the sensitive components of the sensor are robust and durable.At the same time,there are problems such as complex signal conditioning,low precision,susceptibility to corrosion,and poor noise resistance.These problems limit the application of thermoelectric temperature sensors.Graphene is a two-dimensional carbon nanomaterial with a variety of excellent properties,As a macroscopic body of graphene,3D graphene aerogel not only inherits the excellent electrical properties of 2D graphene,but also has good thermal insulation properties.Theoretically,the 3D graphene aerogel and its composite materials have good thermoelectric properties and can be used as thermoelectric sensing materials with excellent properties.Therefore,this paper studied three preparation methods:template preparation,3D printing and doped printing,and obtained RGA,3DGA and its composite material with different microscopic morphological characteristics and different macroscopic properties.At the same time,the influence of preparation method,shape structure,doped phase relative thermoelectric properties of RGA,3DGA and its composite materials are analyzed,which provides theoretical basis and technical support for the research with thermoelectric and sensing properties of aerogel materials.The specific research content of this article is as follows:Firstly,three-dimensional reduced graphene aerogels(RGA)with different densities and microstructure characteristics were prepared by adjusting the process parameters of template method.Based on the 3D printing method,the controllable preparation of graphene aerogel(3DGA)and its composites(graphene/Bi₂Te₃)with different network structures was realized by adjusting the design network structure and the printing paste.By means of SEM,TEM,EDAX,XRD,FTIR and Raman,the microstructure?element distribution?bonding mode and phase composition of the three materials were tested and analyzed.Secondly,the thermoelectric properties of different preparation processes and phase composition of RGA,3DGA and its composites were explored by testing the Seebeck coefficient,electrical conductivity and thermal conductivity,so as to realize the regulation of unilateral properties of RGA,3DGA and its composites by changing the preparation methods and process parameters.The optimal ZT value was obtained by integrating relevant data,and the thermoelectric properties and thermoelectric conversion efficiency of RGA,3DGA and its composites were analyzed.Finally,the sensor model was designed to test the temperature rise sensing characteristics,repeatability and stability of the model.The thermoelectric sensing properties of RGA at different reduction temperatures were tested.The thermoelectric sensing characteristics of the model under different vacuum degrees were tested.The thermoelectric sensing characteristics of the model in different composite phases were tested.Design water temperature meter,thermometer and simulate test.