Development Of Energy Generation And Storage Device Based On Textiles

With the development of science and technology,more and more wearable intelligent electronic products walk into people's daily life.However,the power sources as an indispensable part of these electronic products remain challenging and urgent task due to their flexibility and poor cruising ability.How to fabricate wearable energy devices becomes one of the important research areas in the field of intelligent materials.Although a great deal of research has been widely explored in recent years,include making people comfortable while wearing them and improving their performances,their practical applications still be limited because of some disadvantages including high production costs,poor flexibility,lower durability and environmental dependencies.To this end,it is critical to further enhance the performance of wearable energy devices by developing new materials and designing novel structures.Textile material is a natural wearable material,its remarkable properties such as wear comfortable,universality and mechanical stability make the textile material become the ideal substrates of the wearable power sources and attract many academic attentions.Up to now,the research of the triboelectric generators based on textiles is still at the initial stage and the most focus of the energy storage areas is active material rather than the textile substrate.More specifically,the substrate of the fiber-shaped energy devices cannot be prepared in large quantities at first,and the length of the fiber-shaped electrodes is very limited.Secondly,it is difficult to realize the high mass loadings in the planar supercapacitor electrode substrate and the porosity and pore configuration of the porous textile substrate also play significant impact on it,and it is necessary to understand their impact in order to obtain high electrochemical performances.Finally,how to integrate the energy producing devices and storage devices based on the textile and make the integrated device achieve self-powered are relatively rare mentioned.In this dissertation,the novel flexible triboelectric generator was fabricated base on commercially available spacer fabric as the energy conversion device,and then the 1D and 2D flexible supercapacitors were fabricated base on the common textile yarn and fabric as the energy storage device.The energy conversion device converts the mechanical energy into electrical energy and stores it in the prepared energy storage device,so as to realize the integrated self-powered wearable energy device.The main contents include the following aspects:?1?The spacer fabrics were selected as the substrate of the triboelectric generator,the lower layer of the fabric was bonded with poly?dimethylsiloxane??PDMS?.Under the action of external force,the PDMS and the PET fibers of the fabric can achieve effectively friction,the special structures of the spacer fabric can spontaneous elastic space for pressing and releasing and consequently separate the electric charge produced by friction on the top and bottom surfaces of the device and convert the mechanical energy into electric energy which do not require the springs or other hard spacers.In addition,the flexible carbon nanotube film was selected as the induced electrode instead of the metal or metal oxides which are generally rigid,stuffy and unsuitable for flexible and portable applications and realize the structural superiority of the whole device.The parameters of the spacer fabric during the preparation process and the conditions of the applied force in the testing process on final output performances of the devices were carefully investigated,and the working principle of the device was revealed.It was found that the output electrical signal of the device was increasing with the increase of the thickness,area of the spacer fabric and applied external force.However,the output electrical signal was decreasing with the increase of the applied force frequency due to the compression rebound hysteresis of the spacer fabric.Under the condition of pressure 400 N and friction frequency of 1 Hz,a peak power density can be achieved 153.8 mW m-2 combined with different resistance of the external load,the open-circuit voltage and current signal can up to 500 V and 20 ?A when the spacer fabric with a size of 5 cm×5 cm and thickness of 8 mm.The electric signals generated by the triboelectric generator device can be rectified and charged energy storage device,when the energy storage device was fully charged,it can be used to light a common micro-electronic components such as LCD and LED.?2?A strong interfacial adhesion is achieved between Polyimide?PI?filament and graphene coating.Alkali treatment with sodium hydroxide solution grants polyimide new functional groups,?i.e.,amide bond and carboxyl bond?,which can react with graphene oxide?GO?and the GO perfectly covers the surface of the PI filament,resulting in a good bonding after the GO reduction of HI.In the process of preparing composite conductive fiber,the effects of alkali treatment and dip coating process on final properties were explored.The results show that the alkali treatment time can effectively control the etching of the fiber surface and affect the amount and fastness of the adsorbed graphene oxide.The properties of the composite conductive fiber are the best when the treatment time is 30 min.Regulation the number of dip coating can effectively control the coating thickness and the final electronic conductivity and electrochemical properties of the conductive fiber.Consequently,a high conductivity of 1.02×103 S m-1 is realized when the number of dip coating is 12,which is also well maintained after a variety of deformation such as bending,twisting and washing.Furthermore,the resultant composite conductive fiber can be directly used as a conductor wire for its excellent conductive property and can be used as electrode material to assemble into a flexible fiber-shaped supercapacitor device.The one-dimensional fiber-shaped supercapacitor energy storage device has excellent electrochemical performance and the volumetric capacitance is increased when decreasing the length of fiber electrode which was investigated by electrochemical testing.In particular,the volumetric specific capacitance is 16.4,12.6,9.5 and 5.9 F cm-3 at current density of 90,180,360 and 720 mA cm-3,respectively.The specific capacitance of the fiber-shaped supercapacitor can be maintained even after 3000 charge and discharge cycles.?3?Polypyrrole?PPy?coated commercial cotton fabric obtained via in-situ chemical polymerization was used as electrode material of supercapacitor.As a porous structure substrate,the structure of the fabric directly affects the porosity and specific surface area of the fabric.The influence of the structure of fabric on the mass loading of final active material and load fastness was studied.It is found that the knitted structure is more suitable for the active material substrate under the same thickness condition compared with the woven and non-woven structure.The fabricated electrode base on the knitted structure has better performance of mass loading,load fastness,electrical and electrical properties which due to its proper porosity and compactness.The different mass loading of the fabric substrate was achieved by adjusting the concentration of chemical polymerization?the range of the concentration of pyrrole monomer was 0.04⁰.22 M?.For the knitted fabric,when the concentration of pyrrole monomer was 0.2 M,the mass loading reached a maximum at 12.3 mg cm^-2.The dependence of the surface resistivity,areal specific capacitance and gravimetric specific capacitance on the pyrrole concentration was then carefully investigated.The results show that the sheet resistance decreased with the increase of the PPy mass loading,when the mass loading exceeded 6 mg cm^-2,the sheet resistance was less than 50 ? ?-1,meanwhile the areal specific capacitances shows an increasing trend and the gravimetric specific capacitances was increased first and then slightly decreased.The PPy coated fabric based on knitted structure displayed the highest electrochemical performance and was assembled into two-dimensional planar supercapacitor which was carefully investigated further.After the electrochemical test,the areal specific capacitances were 4117,3553,2956,2516 and 2212 m F cm^-2 at the current density of 2,5,10,15 and 20 mA cm^-2,respectively.The prepared energy storage devices also exhibit good flexibility and stability,importantly,the specific capacitances remained almost unchanged even after bending or twisting 500 times.A red light-emitting-diode?LED?could be powered by three supercapacitors through a simple series.?4?In order to realize the preparation of self-powered integrated energy devices,the triboelectric generator was used as energy conversion part and the supercapacitors based on textile was worked as energy storage part.The results showed that the triboelectric generator device can effectively convert mechanical energy into the energy storage device which equivalent to charge the energy storage device,and the energy storage devices can be utilized to directly drive some micro-electronic components such as LCD display and LED Lamps.In summary,this work concentrates efforts on the development of textile-based energy generation and storage devices,including a flexible triboelectric generator,one-dimensional and two-dimensional supercapacitor.All the devices not only show their electronic performances but well retain the flexibility and wearability of traditional textiles.Finally,a self-powered energy device was obtained through simple assembly of the developed energy generation and storage units.With the device several application cases have been demonstrated.With the new design and fabrication concept provides by this work would be a significant step forward in promoting the development of wearable and smart electronics.