Study On The Preparation And Performance Control Of Ceramic/Polymer Composite Materials For Energy Storage And Energy Harvesting Applications

With the development of electronic equipment in the direction of miniaturization,portability and flexibility,traditional dielectrics can no longer meet the needs of the industry.It is of great significance to develop ceramic/polymer composite dielectrics with high dielectric and high-voltage electrical properties in the fields of energy storage devices and self-driving systems.This thesis takes ceramic/polymer composite for dielectric energy storage and piezoelectric energy pickup applications as the research object,the composite are prepared by filling the polymer matrix with ceramic particles of different morphologies.The characteristics of dielectric energy storage and piezoelectric energy pickup of composite have been systematically studied,and the mechanism of performance enhancement and application prospects have been explored.The hydrothermal synthesis of barium titanate nanowires（BT NWs）with high aspect ratios was studied.By adjusting the growth process parameters,BT NWs with regular morphology,uniform particle size and tetragonal phase structure were prepared.Using it as a ceramic filler,a BT NWs/polyvinylidene fluoride（PVDF）nanocomposite was prepared,and its dielectric and energy storage properties were studied.The dielectric properties and energy storage characteristics of the composite filled with BT NWs have been significantly improved.At a frequency of 1 k Hz,the dielectric constant of 30 vol%BT NWs/PVDF composite material reaches 45,which is about 4 times higher than that of pure PVDF,and the dielectric loss is 0.017.The finite element simulation is used to study the mechanism of energy storage density increase of composite.The results show that nanowires have significant advantages over nanoparticles in increasing energy storage density,and can play a role in connecting highly polarized regions in composite.The composite material has broad application prospects in high energy storage density capacitors and other fields.The controllable preparation of BT sponge polymethyl methacrylate（PMMA）microsphere array template method,the controllable preparation of vacuum defoaming and capillary penetration of BT sponge/epoxy resin composite,and the controllable preparation of composite,and dielectric and energy storage characteristics have been studied.The results showed that a three-dimensional BT sponge with adjustable voids and uniform microstructure was successfully prepared.The composite material prepared with the filler has good filler-matrix compatibility.The BT sponge/epoxy resin composite material has significantly improved dielectric properties and energy storage characteristics,with a dielectric constant of332,and an energy storage density of 105×10^-3 J/cm³ under an electric field of 100 k V/cm.The results of finite element simulation and Kelvin probe microscan（SKPM）experimental observation revealed the internal mechanism of the composite material.The three-dimensional BT structure achieved a large value of local electric displacement,which improved the overall dielectric and energy storage characteristics of the composite material.The composite material has good application prospects in embedded capacitors and electrostatic energy storage devices.The hydrothermal synthesis of three-dimensional flower-like barium titanate（BTFs）ceramic particles,the filling of BTFs and carbon nanotubes（CNTs）in polydimethylsiloxane（PDMS）to form BTFs-CNTs/PDMS composite,and compression the preparation of electrical nanogenerator（PENG）and the piezoelectric energy pickup characteristics of PENG.The filling of BTFs realizes the improvement of the continuity of the filler in the composite material,thereby improving the electrical output performance of the composite material.When the filler content is 15 wt.%,the instantaneous output power of PENG is 1728μW,which is two orders of magnitude higher than that of polymer composites filled with BT nanoparticles（NPs）.PENG has shown good durability through the cycle test,and can drive low-power electronic devices and collect biological kinetic energy.In addition to the enhanced continuity of the filling body,the filling of BTFs also achieves high local stress at the petals,which makes the overall electrical output performance of PENG improved.The PENG has broad application prospects in the field of biological sports energy harvestingThe hydrothermal synthesis of three-dimensional flower-like lead titanate（PTFs）ceramic particles with high curie temperature was studied,and they were filled into high-temperature resistant polyimide（PI）,and PTFs/PI were prepared by in-situ polymerization.The morphology,structure,piezoelectric energy harvesting characteristics of PTFs/PI PENG and the application under high temperature environment are studied.The PENG exhibited good thermal stability in the cycle test from room temperature to 300°C,and successfully collected the vibration energy of the automobile engine.The results of XRD residual stress test and finite element simulation show that the mechanism of PENG output performance enhancement is the high local stress caused by the morphology of the flower-shaped filling body.The PENG shows good application prospects in high-temperature micro-energy collection.