Potential Applications Of Carbon Nanotube Macrostructures In Energy And Sensing

Carbon nanotube?CNT?macroscturctures are assemblies with large amount of carbon nanotubes.They inherit outstanding properties of individual CNTs and can be handled easily.CNT macroscturctures show potential applications in many areas,especially in energy and sensing area.In this thesis,CNT macrostructures of continuous CNT film and carbon nanotube mesh?CNTM?are prepared.The CNT macrostructures are used to fabricate highly conductive CNT fibers,flexible supercapacitors and strain sensors.The work is meaningful for the industrial preparation and application of CNTs and can provide ways for wearable devices in energy supply and sensing signals acquisition.Firstly,continuous CNT film and CNTM are prepared by an improved chemical vapor deposition method.By modifying the experimental set-up,choosing proper carbon source and tuning the carrier gases,excellent CNT thin film can continuously grow and be collected.By using nickel gauze as substrate and feeding the carbon source slowly,CNTM with well-defined macroscopic grid structure can be prepeared.Then,desnse CNT fibers are fabricated from the continuous CNT films by drawing through diamond wire drawing dies and rolling by a roller.The electrical conductivity of the CNT fibers are improved significantl y by chemically doping with nitric acid and iodine,respectively.The CNT fiber showing outstanding electrical properties,with the best electrical conductivity of 9.44×10⁶ S/m and high current carrying capacity of 4.25×10⁵ A/cm²,respectively.All-solid-state,flexible supercapacitors basing on CNT-MnO_x composite films are fabricated by electrochemically deposit MnO₂ on CNT films.The supercapacitors basing on CNT-MnO_x composite films have outstanding capacitive properties,with a high specific capacitance of 73.4 F/g,energy density of 2.8⁶.2 Wh/kg and power density of 0.2¹.3 kW/kg.The supercapacitors showing good stability when bent to different angles,kneaded or cut into two pieces.All-solid-state,CNT-Polypyrrole?PPy?fiber supercapacitors are fabricated by electrochemically deposit pyrrole on CNT films and drawing the composite films through wire drawing dies.The specific capacitance,energy density and power density of the supercapacitors are 69 F/g,3.6⁴.7 Wh/kg and 0.4³.8 kW/kg,respectively.The fiber supercapacitor are stable when they are bent to different angles or twisted to different coils,or undergo static and dynamic stretching.The supercapacitors are also reliable in a wide temperature range of-27⁶1?.Finally,CNTM are used to prepare CNT-PPy mesh supercapacitors and strain sensors.The areal specific capacitance of the supercapacitor basing on CNT-PPy mesh is 5.11 mF/cm².Owing to the structure of the electrodes,the supercapacitors are stable when they are bent,stretched to large strain of 20%.The stretchable and the compressible strain sensors are constructed basing on the CNTM.The strain sensors can work in 1⁵0%strain range,showing good sensitivity,quick response and good reproducibility.The strain sensors basing on CNTM show potential applications in human healthcare monitoring and human motion activities detection.