Research On Electrode Materials Of Flexible Supercapacitor Based On One-dimensional Textile Fibers

With the progress of human civilization and the development of science and technology,the non-renewable fossil fuels on the earth,including coal,oil and nature gas etc,has gradually been exhausted,thus leading to the imperative problem of energy.At the same time,the problems of global warming and environmental pollution caused by the consumption of fossil,have threatened the survival of all human beings and also attracted worldwide attention.Therefore,the development of environment-friendly and renewable new energy is urgent to prevail these non-renewable energy sources,and overcame the difficulty that all humans are facing together.With the rapid development of science and technology,scientists have carried out extensive research on electrochemical energy storage systems,especially in the fields of lithium ion batteries（LIBs）and supercapacitors（SCs）.These new energy storage systems are widely used in electronic products and new energy vehicles.However,with the progress of social demands and consumptions,wearable devices in flexible electronics have attracted considerable research attention in recent years.As a new type of energy storage device,fibrous flexible supercapacitor not only has the advantages of high power density,long cycle life,excellent rate performance significant environment profit and safety,but also has the characteristics of small volume,light weight,strong braidability,etc.With the rapid research progress in the field of portable portable and wearable electronic equipment more and more research interest about the electrodes of fibrous flexible supercapacitors,focuses on metal fibers,carbon-based fibers and so on,but less on textile fibers.As we all know,textiles are widely used in wearable fields.Hence,the fibrous flexible supercapacitor of aramid textile yarn is selected as the research object in this paper.The electrode materials and their properties of aramid textile fiber-like flexible supercapacitor were studied as follows:Conductive Nickel is deposited on the surface of one-dimensional textile yarn by chemical deposition method to improve the non-conductive characteristics of textile yarn.At the same time,electroless nickel layer can be used as electrode material.Through the research on its conductivity and electrochemical performance,we have obtained that the resistance of aramid fiber after nickel plating improvement is approximatlly 4.3Ω.At the scanning speed of 100 m V/s,the specific capacitance of a single nickel-plated aramid yarn is calculated to be 4.0 m F/cm.Through parallel testing of six nickel-plated yarns,the specific capacitance is increased to 6.8 m F/cm at the same scanning speed,thus providing a reference for the application of textile substrate materials in the field of flexible wear.Vulcanizing the one-dimensional fibrous nickel-plated yarn and growing in situ to obtain the aramid textile yarn of the one-dimensional nickel sulfide electrode material.The resistance value measured by a multimeter during digital display is about 1.0Ω,which greatly improves the conductivity of the insulated aramid yarn,thus further improving the specific capacitance of the electrode material based on textile fabric.Through electrochemical tests,we have obtained that the specific capacitance of a single nickel sulfide aramid fiber at 100 m V/s sweep rate is 13.3 m F/cm,and a specific capacitance of31.1 m F/cm is obtained by connecting 6 fibers in parallel.At the same time,the specific capacity of one-dimensional NiS electrode material is still 86%after 1500 cycles at a current density of 1 m A/cm.This performance can basically meet its application in the field of flexible intelligence.Based on the excellent conductivity of nickel sulfide electrode material,one-dimensional aramid textile fiber of NiS@MoS₂ electrode material was obtained by coating a layer of molybdenum disulfide nano sheet on NiS by hydrothermal synthesis method.The resistance is approximately 1.5Ω,and the specific capacitance at 100 m V/s is 18.5 m F/cm.The specific capacitance of nickel-plated aramid yarn is larger than nickel sulfide and nickel-plated aramid yarn.Although the resistance of aramid fiber slightly increased,the composite material system can form a uniform heterogeneous interface,which has a good synergistic effect with nanofibers and can ensure the enhancement of electrochemical activity of the active material in the circulation process.The formed composite system effectively increases its voltage window,which is conducive to improving the energy density of supercapacitors to a certain extent.