Preparation And Performance Study Of Energy Harvesting Devices Based On Electrostatic Spinning Method

As wearable devices and small electronic devices continue to evolve,the size of these devices is continuously moving toward the micro-nanometer scale.The application demand for flexible and lightweight self-powered devices is increasing due to size and application scenarios.Triboelectric nanogenerator(TENG)is promising for powering small devices,but there are problems such as low output power and ineffective utilization of the generated power.In this paper,we focus on the effects of different doped particles on the electrical properties of electrostatic spinning TENG,and then we verify the practical application performance by forming a power supply and storage system with high performance supercapacitors,as follows.(1)MoS₂/CNT(carbon nanotube)nanopowder was prepared by hydrothermal method and doped in PVDF(polyvinylidene difluoride)and prepared electrostatic spinning as friction layer with nylon cladding as friction substrate to prepare TENG.The effects of spinning fiber thickness and Mo S₂/CNT doping concentration on the electrical output performance of TENG were first investigated.It was concluded that the best electrical output performance of TENG was obtained when the Mo S₂/CNT concentration was 0.3 wt%,and the electrical output was increasing with the increasing operating frequency and external shock,with V_oc up to 300 V and I_sc about 11.5?A.Then the TENG was placed on the human body to collect human mechanical energy to test the performance of practical applications,and the output power in the walking and running states was also in line with the results of the theoretical experiments.I_sc can be maintained at 12.5?A when the TENG is cycled for2000 s.Finally,when the TENG is tested after being left for 6 months,30%of the original performance can still be maintained.(2)The accordion-like MXene two-dimensional inorganic particles were obtained by directional etching of the Al atomic layer in Ti₃AlC₂ using hydrofluoric acid.MXene was added to PVDF to prepare electrostatic spun fibers,and there was a significant improvement of?-crystals in the obtained fibers.Then EC and PVP were mixed to prepare electrostatic spun fibers,and the EC/PVP filament formation was better compared to pure EC.The two electrostatic spinning were used as friction sub-preparation to prepare TENG to test the electrical properties.By changing the concentration of MXene in PVDF to seek the best electrical output performance when and corresponding to the MXene concentration,it was determined that TENG electrical best when the MXene concentration is 4 wt%,then we change the operating conditions to determine the best electrical output when the external force impact 20 N,operating frequency 1.6 Hz,V_oc can reach more than 300 V,Isc is about7?A.At an external load of about 10⁸?,the load power is about 0.83 m W.Finally,the cyclic stability of the TENG was verified,and the Isc was still stable above 10?A under the optimal operating conditions for 3000 s continuously.(3)In order to obtain a good performance of the supply and storage system,we chose carbon and nickel foam with good electrical conductivity to prepare the double-layer supercapacitor,and tested the cyclic voltammetric curve and constant current charge/discharge curve to verify the electrochemical performance of the supercapacitor.The peak shape of CV curves at different scan rates always remained constant;the specific capacitance was 46.5 m F·cm^-2 at a current density of 15 m A·cm^-2 and still possessed 89%of the initial capacity for 10,000 cycles at 15 m A·cm^-2,which proved the good charge/discharge performance of the supercapacitor.Finally,we connected the TENG with the prepared supercapacitor to form a supply and storage system,and proved that the TENG can fully charge the supercapacitor in about 300 s of operation by testing the OCPT curve,which proves that our supply and storage system has good performance.