Research On Charge Replenish Enhanced Triboelectric Nanogenerator And Its Application

As a new era of energy harvesting technology,triboelectric nanogenerators(TENGs)have been widely applied in different fields.At present,the reason that restricts the further commercialization of TENGs is its low surface charge density.Therefore,it is necessary to explore new methods to improve the surface charge density of TENG.As the driving motion for the flow of electrons in the external circuit,the amount of friction charges in the friction layer is vital to the TENG output performance,more friction charges will help to bring greater output power of TENG.In this thesis the existing methods to improve the surface charge density of friction layer are summarized.From the aspects of experimental design,structure optimization,mechanism exploration,output characteristics analysis and application development,according to the essence of improving the surface charge density of friction layer to promote the further optimization of TENG,a charge-replenish strategy is proposed and explored.Based on the idea of breaking the original charge loss equilibrium and establishing a new equilibrium,this scheme improves the output performance of TENG from a new perspective.(1)In this thesis,a charge-replenish enhanced TENG is proposed.The TENG can supplement electrons for the electronic donor layer of the TENG by absorbing electrons from the earth.The additional electronic replenishment will break the charge loss equilibrium in the original friction layer,and increase the maximum charge carrying capacity of the friction layer by establishing a new equilibrium,thus improving the output performance of the TENG.In this chapter,a composite electrode structure was designed in the experiment,the reasons for adding the dielectric layer and the optimization of the dielectric layer thickness of the composite electrode structure were investigated.The important effect of adding the dielectric layer on the charge replenish strategy was fully verified through the comparison experiment,and the optimal dielectric layer thickness value was given.Under the experimental conditions,the electrical signal of the TENG before and after the charge replenish strategy was increased by 2 times,and the output power was increased by 10 times.At the same time,the mechanism of charge replenish strategy to enhance the performance of TENG through the design of the experimental scheme were also explored.We confirmed that the electrons in the earth did flow into the TENG and the inflow of these tiny charges can cause a significant increase in TENG output.(2)In addition,this thesis analyzes the output characteristics of charge-replenish enhanced TENG,and sets a series of application scenarios according to its output characteristics.We focused on the influence of driving force and driving frequency on the experimental model,and proved that the influence of driving frequency on the model is different from that of traditional TENG.The increase of driving frequency will not only increase the separation rate of friction charges,but also increase the input rate of electrons from the ground end to the friction layer,which will play a dual role in improving the output of TENG.Therefore,we think this experimental model is more suitable for some high-frequency energy collection scenarios.In order to verify the improvement effect of the experimental model in the high-frequency scene,we tested its performance in the field of sound-wave energy collection,and explored the optimal experimental conditions under the condition of sound-wave driven.In the experiment,we invertigated the influence of these two factors on the electrical signal of the sound wave driven triboelectric nanogenerator(STNG)by controlling the loudness and frequency of the sound.The results show that the STNG reaches the maximum output at the sound frequency of 190 Hz and the loudness is positively correlated with the STNG electrical signal.Through the analysis of the experimental data,we found that the charge-changing rate caused by frequency is greater than that caused by other factors before and after the charge replenish,which shows the special role of frequency on this experimental model.When we use the optimal sound frequency and loudness conditions and adopting the charge-replenish strategy for subsequent experiments,the output electrical signal of the GSTNG increases by two times and the output power increases by 200 times after the adjustment of the chargereplenish strategy.(3)Based on the mechanism analysis and application exploration of the charge-replenish strategy,we developed and prepared a wind energy collection nanogenerator driven by the vortex-induced vibration effect(WTNG).In this chapter,the effectiveness of vortex-induced vibration and the effective parts were analyzed and verified.The friction layer materials and the parameters of the designed model are optimized for the experimental model,so as to obtain the best parameters suitable for this experimental model.On the basis of the optimal conditions of the experimental model and the charge-replenish strategy mentioned above,we build a WTNG with the charge-replenish strategy(GWTNG),and expect to transfer the electrons in the earth to the friction layer for charge supplement,in order to enhance the wind energy collection efficiency and improve the output power.After testing,the maximum power of the GWTNG is increased by 85 times after the charge-replenish strategy is adopted.In addition,a piezoelectric-triboelectric composite nanogenerator driven by vortex-induced vibration(HTNG)is designed to promote the wind energy collection,and the piezoelectric unit is used to supply the charge of the friction unit,so different charge-replenish methods are expanded.In this thesis,the feasibility of using piezoelectric unit to replenish charges for friction unit has been verified through the design of experiment,and it will pave the way for exploring more efficient charge-replenish methods.