Design,Fabrication And Test On Piezoelectric And Triboelectric Energy Harvester

Recently,wireless sensor networks,wearable devices and implantable devices have been developed.However,there is still a problem which is efficiently appling energy for these devices.At the moment,they are usually integrated with a chemical battery.Although their energy density and working life have been improved,these chemical batteries will still exhauste.In consideration of the extreme environment of wireless electronic devices,it is impossible to replace the chemical batteries.If we could harvest energy from the outside environment,energy supply for these wireless electronic devices will not be a problem.As a result,energy harvesting technology has attarct attention from researchers from all of the world.In this paper,we have proposed a MEMS based piezoelectric energy harvester.Its working mechanism is based on piezoelectric effect of piezoelectrical materials.Under outside vibration sources,the stress and strain will lead to the polarization phenomenon in the piezoelectric materials.And positive and negative charges will appear on the up and bottom electrodes.With the development of integrated circuit and miniaturizaiton of electronic devices,MEMS technology is widely applied to fabricate energy harvesters.Energy harvesters fabricated by MEMS have advantages such as simple structure,high output energy density and mature fabrication technology.The piezoelectric energy harvester proposed here has 9.2 V output voltage and 57.6 ?W output power under 1 g acceleration of vibration source and 5.32 V output voltage and 20.2 ?W output power under 0.5 g acceleration of vibration source.In this paper,we have proposed a PDMS and PDMS/MWCNT based triboelectric nanogenerator.Triboelectric nanogenerator is based on coupled triboelectrificaiton and electricstatic induction.In the internal part,electrons will transfer from one tribological material to another triboligical material due to their different charge affinities.In the outside part,free electrons will flow between the up and bottom electrodes under electrical potentials.The 10wt% fabricated triboelectric nanogenerator has 130 ?W maximum output power while the 2wt% fabricated triboelectric nanogenerator has 120 ?W maximum output power.The internal impedance are 6 M? and 8.5 M?,respectively.It is concluded that the 10wt% triboelectric nanogenerator has improved output performance compared to the 2wt% triboelectric nanogenerator.In this paper,we also have proposed an integrated flexible harvester coupled triboelectric and piezoelectric mechanisms using PDMS/MWCNT and PVDF.This energy harvester has good flexibility,biocompatibility.The peak-peak voltages of triboelectric and piezoelectric device are 30 V and 6 V at the frequency of 5 Hz under the tapping force of 5 N,respectively.The maximum powers of triboelectric and piezoelectric are about 3.4 ?W at the optimized loading resistance of 15 M? and 0.12 ?W at 1 M? external loads,respectively.