Preparation And Thermoelectric Properties Of Tellurium-based Inorganic Nanostructures/poly(3,4-ethylenedioxythiophene) Composites

Thermoelectric materials are a kind of functional materials that directly realize the mutual conversion of thermal energy and electrical energy through carrier transport within the material.With the increasing shortage of energy and the increasingly serious environmental pollution,thermoelectric materials are considered to be a promising energy alternative medium in the future and have broad application prospects.Although traditional inorganic thermoelectric materials have relatively high thermoelectric properties,their raw materials and processing equipment are expensive,heavy metal pollution and limited resources,etc.,which limit their wide application.In order to realize the practical use of thermoelectric materials,it is necessary to seek high-performance and low-cost thermoelectric materials.Conductive high molecular polymers and their derivatives have the advantages of low thermal conductivity,low price,light weight,easy synthesis and processing,and have gradually become the research focus of thermoelectric materials.Te is a narrow band gap semiconductor with a high Seebeck coefficient at room temperature.However,the conductivity of Te nanorods is very low and the environmental stability is poor,resulting in a low power factor,which hinders its application in thermoelectricity.Secondly,Te has a high thermal conductivity,which is not conducive to increasing the ZT value of thermoelectric materials.Because conductive polymers have many advantages such as low thermal conductivity,low price,light weight,easy processing and synthesis,etc.,new ideas for the development of traditional thermoelectric materials are provided.Poly 3,4-ethylenedioxythiophene(PEDOT),as a promising conductive polymer,has the advantages of high electrical conductivity,low density,low thermal conductivity and good thermal stability.However,due to the insolubility of PEDOT polymer,its application is limited.Usually,polystyrene sulfonic acid(PSS)with good water solubility is used as the counter ion to dope to improve its water solubility.However,PSS is an insulating phase and the doping process is complicated,which reduces the conductivity of PEDOT:PSS.Preparation of organic/inorganic nanostructured composite thermoelectric materials by appropriate methods will make it possible to exert their respective advantages and even produce synergistic effects,thereby improving the thermoelectric properties of the composite materials.First,PEDOT:PSS-coated Te nanorods(P-Te)were synthesized by in-situ polymerization.The prepared P-Te nanorods have good dispersion and stability in aqueous solution.The introduction of conductive polymer coating has greatly improved the thermoelectric performance of Te nanorods.The power factor is 22.93?W/m K²,which is nearly 13 times higher than that of pure Te nanorods.One-dimensional PEDOT nanowires(PEDOT NWs)were prepared by the micellar soft template method,and the conductivity was as high as 687.29 S/cm.They were combined with P-Te nanorods by vacuum filtration to prepare P-Te/PEDOT NWs composite film.Compared with P-Te nanorods and PEDOT NWs,the power factor of the composite film is improved,and the power factor is significantly improved to 47.18?W/m K².Then,the cotton fiber fabric is used as the substrate,and a simple dipping method is used to coat the cotton fiber with a P-Te solution with good water solubility as a P-type cotton fiber.The prepared single-walled carbon nanotube dispersion was coated on cotton fiber,and treated as N-type cotton fiber after being treated with polyethyleneimine(PEI)and sodium borohydride(Na BH₄).A flexible wearable thermoelectric power generation device based on ordinary cotton fiber is designed.The device will produce 14.8 m V output voltage when the temperature difference between the human arm and the environment is about 13.5 K,providing ideas for the application of thermoelectric materials in the field of flexibility and wearable.