Research On MEMS Triboelectric/Piezoelectric Hybrid Flexible And Wearable Energy Harvester

With the rapid development of Body Area Network(BAN),wearable/implantable wireless low-cost devices faced new challenges to their power supplying.Traditional wearable/implantable medical devices mainly used batteries as their electric power.Although there were several advantages in their power density and stability,batteries' changing limitless of life time still didn't satisfy more and more complicated environment application requirement.If it could scavenge energy from the circumstance of sensors converting to electricity persistently,for example the mechanical energy in the BAN,the self-powered system not only solve the problems from batteries,but also decrease the maintain cost of the net node.Thus,we proposed flexible triboelectric and piezoelectric hybrid energy harvesters,and applied them to wearable self-powered system.The mainly works are flowing:1.We established the theoretical model of parallel-plate contact-mode triboelectric generator and single-friction-surface triboelectric generator.Based on them,we proposed two triboelectric/piezoelectric hybrid generators,of which parallel-plate contact-mode and single-friction-surface mode,respectively.We designed and optimized structure of generator,and analyzed their working mechanism.2.We fabricated P(VDF-TrFE)nanowires by electrospinning process,and PDMS/MWCNT composite membrane.By SEM,XRD and FTIR,the morgraphy of P(VDF-TrFE)nanowire was shown diameter of 200 nm,distributed uniformly on the membrane,and consisted obviously piezoelectric ? crystalline phase.At the same time,thePDMS/MWCNT membrane consisted uniform pillars with 50 ?m height,well-dispositioned MWCNTs.3.The testing platform was designed.We analyzed the open/close-circuit triboelectric and piezoelectric performance under the circumstance of human finger pressing(about 5N pressure).The hybrid output performance was discussed,and the relationship between output voltage and finger pressure were tested as a pressure sensor.Meantime,in order to optimize the device performance,we proposed five different devices to compare their outputs4.The PDMS,AZO and P(VDF-TrFE)were chosen and fabricated a transparent single-friction-layer triboelectric and piezoelectric hybrid energy harvester.By SEM,XRD,FTIR,UV-Vis and tensile testing,the results shown that we obtained arrayed uniform pyramid structures,and P(VDF-TrFE)thin film consisted obviously ?piezoelectric phase.The device possessed 60.77% transparency in the visible vision,with good stretchability of 75.83%,and 2.68 MPa Yong's modulus.5.We studied and applied the flexible and wearable transparent single-friction triboelectric/piezoelectric hybrid generator.The platform was established,and the output performance was analyzed under hand force.The open/close-circuit triboelectric and piezoelectric performance was tested.The hybrid performance was measured and their charges were discussed respectively.Meantime,we attached the device on the neck,arm,finger and ankle to monitor the moving.We achieved the motion signals and analyzed their characters.