Research On Coaxial Hybrid Nanogenerator And Harvesting Low Frequency Water Wave Energy

In recent years,triboelectric nanogenerators(TENG)have shown unique performance in harvesting low-frequency ocean wave energy into electrical energy,becoming a potential technology for developing new distributed sustainable energy sources.But,the output power of TENG is still low.In order to increase the power of the generator,TENG often use to build hybrid nanogenerator with electromagnetic generator(EMG).However,the working principles of TENG and EMG are different.TENG outputs high-voltage and lowcurrent signals at low frequencies.While,the EMG outputs low-voltage and high-current signals.How to take the advantages of both is the difficulty of building an electromagnetic-triboelectric nanogenerator.In this paper,the high voltage of TENG and the high current of EMG are simultaneously obtained through the same frequency and in-phase motion of TENG and EMG.Highvoltage-high-current electrical signals are obtained,which provides a new technology for the development of high-performance hybrid nanogenerators.The main research contents of this paper are as follows:(1)Based on the coaxial design,a hybrid triboelectric-electromagnetic nanogenerator which consists of multi-layer contact-separation TENG and EMG.Due to the coaxial swing arm,a high-voltage and high-current output could be achieved when the EMG and the TENG were connected in parallel after rectification and moved in the same phase.The effect of frequency on the performance of the device was tested.It was found that with the increase of frequency,the performance of the coaxial hybrid nanogenerator is increased.The open-circuit voltage is 178.4 V at 1.5 Hz,and the short-circuit current is 1.6 m A.When frequency of water wave is 1.0 Hz and the wave height is 20 cm,an opencircuit voltage of 189.07 V and a short-circuit current of 1.89 m A are obtained.(2)Six coaxial hybrid nanogenerators are used to form an array,and their properties and applications are explored.The TENGs is rectified and connected in parallel.The EMGs are connected in series and then rectified,and then connected in parallel with the TENGs.Under the excitation of water wave with the frequency of 0.8 Hz and wave height of 20 cm,the coaxial hybrid nanogenerators array outputs a peak voltage of 194.02 V and a peak current of2.59 m A.It charges a 2.2 m F capacitor for 300 s,and the voltage of the capacitor is 6.61 V.When charging a 13.2 m F capacitor for about 7.5 minutes,it can drive a thermo-hygrometer with a Bluetooth module.Charging the 22 m F capacitor for33 minutes can drive the RF module.After designing a suitable circuit,the 35 m Ah lithium battery can be charged.(3)The performance of the coaxial hybrid nanogenerator was further optimized.A foam layer is used to increase contact.After that,the number of the TENG is reduced to reduce the weight and increase the separation distance between the two dielectric materials in the TENG.The open-circuit voltage of the optimized device is increased to 351.23 V.Using the newly hybrid generator to form an array,under the same conditions,the open-circuit voltage is increased to392.34 V,the short-circuit current is 2.12 m A.Finally,charge the 2.2 m F capacitor for 300 s,and the voltage of the capacitor is increased to 8.02 V.Triggered by low-frequency motion,our proposed coaxial hybrid nanogenerator has excellent performance in energy harvesting.It can charge lithium batteries.It has broad prospects for self-driven sensors applied to the ocean.