Study On Polymer Gels And Their Applications For Energy Storage And Conversion

To fulfill the requirement of mass production and daily life convenience,the development of flexible,functional and high-performance energy storage and conversion system is to bring the future to present.Research work on energy conversion materials with high efficiency are the key to converting clear,sustainable energy in nature,such as solar energy,wind energy,geothermal energy and osmotic energy to controllable energy.Polymer gel materials are cross-linked polymers with both hydrophilic and hydrophobic unit,and a three dimension network is formed with the absorption of solvent.For its flexibility,hydrophilibility and adjustable swelling ratio,polymer gel materials can be manufactured with responses to light and heat and applied to photo-to-work conversion and thermal-to-work conversion.Beside,for its flexibility,high binding strength,ion conductivity and spontaneous porous structure,polymer gel materials are applicable for alkaline ion batteries and supercapacitors.With flexibility and high porosity,polymer gels are ideal materials for flexible or stretchable electrode materials;with high binding strength and ion conductivity,polymer gels can be made into binders and gel electrolytes.We have put our attention to theoretical and practical study on hydrogel and organo-gel.In Chapter one,according to previous reports,the application of polymer gel materials in energy storage and conversion is summarized from two aspects:material design and functional applications.Main topics:(1)physical and chemical properties and promising applications of polymer gels;(2)the energy storage mechanism and multifunctional applications of conducting polymer materials;(3)flexible batteries,stretchable supercapacitors,potassium ion batteries and organic polar materials,the application and improvement of gel electrolytes;(4)the classification and mechanism of stimulus response materials,focusing on the application of light sources.In Chapter two,we introduce the basic reagents used in our experiments,the involved basic experimental devices and characterization equipment.In Chapter three,we synthesized and characterized a programmable polymorphic polymer hydrogel membrane that responds to multiple stimuli.The hydrogel membrane can convert light energy,heat energy and osmotic energy into kinetic energy.The prepared multi-responsive membrane has different responses to different stimulus sources,and various appropriate applications have been developed according to the characteristics of the stimulus sources.For example:(1)for uniformly applied stimulus to heat,salt ion concentration and so on,we developed an actuator with overall deformation;(2)for uneven heat,salt concentration and local illumination,we developed writing and erasing functions,2D to 3D shape changes and carrying cargos.In Chapter four,a shape memory polymer hydrogel fiber has been prepared,which can change between multiple states in response to humidity,and has different mechanical properties in different states.In Chapter five,a conductive stretchable hydrogel electrode material with a bi-phase porous structure was prepared and applied to stretchable supercapacitors.Obtained supercapacitors have outstanding performance of high specific capacity,high energy density and high power density.The manufactured symmetric stretchable supercapacitor can provide energy supply under low temperature and repeated stretching conditions.In Chapter six,a hydrogel enabled self-standing polypyrrole potassium ion battery cathode material without adding conductive agents and binders has been prepared.And the following conclusions can be drawn:(1)The capacity of polypyrrole in a potassium ion battery is closely related to the type of dopants;(2)The dissolution process of the dopant can be alleviated by coating a layer of iron oxide on the separator;(3)The conducting polymers with high conductivity,self-standing capability,low temperature resistance,high theoretical specific capacity and cheap,accessible elements is an ideal material for potassium ion battery electrode materials.In Chapter seven,poly(butyl-methacrylate)nanospheres with fast organic absorption rate has been prepared and studied.After coated with a layer of conducting polymer,a high-performance gel material,namely PP nanospheres,with high ionic conductivity,high electronic conductivity and high viscosity is obtained.This material is utilized to synthesize potassium ion cathode material,Prussian blue analogues in situ.In the obtained composite material,Prussian blue nanoparticles are internally connected by PP nanospheres,so the prepared material exhibits excellent rate and cycle performance.In Chapter eight,conclusions have been drawn and prospects have been discussed regarding the work in this paper.