| Triboelectric nanogenerator is a small power generation device that uses triboelectricity and electrostatic induction.It can collect environment mechanical energy and take advantage of it for power micro-nano devices.Since the invention of triboelectric nanogenerators,it has received great attention due to its high output,simple structure and low cost.In the actual working process of the triboelectric nanogenerator,the source of external mechanical energy is constantly changing,and its frequency and amplitude will change within a certain range with time,which leads to the working state change of the triboelectric nanogenerator in practical applications.The systematic study of the performance changes of triboelectric nanogenerators under different working conditions is of great significance to the design and application of triboelectric nanogenerators.However,the research in this area is still on the changes of the output current and output voltage of the triboelectric nanogenerator with the working state until now.And the charge accumulation,the output change under different load states and the load matching situation of the triboelectric nanogenerator have not been studied.In this paper,two structures commonly used in triboelectric nanogenerators are used: contact-separation triboelectric nanogenerators and rotating-disk triboelectric nanogenerators.The relationship between the working frequency and performance of triboelectric nanogenerators is systematically studied.The research results show that:1.The output voltage and output current of the triboelectric nanogenerator both increase with the increase of the working frequency,but the effect of frequency on the output current is higher than that on the output voltage;2.The transfer charge density of the triboelectric nanogenerator is only slightly increased at different frequencies,indicating that increasing the frequency can slightly increase the charge density on the surface of the friction layer when the friction reaches equilibrium,but the effect is small;3.In the early working stage of the triboelectric nanogenerator,as the working frequency increases,the charge accumulation speed becomes faster,but the amount of charge generated by each friction of the triboelectric nanogenerator does not change significantly;4.For different loads,the output power of the triboelectric nanogenerator increases with the increasing of frequency.At the same time,the optimal load also changes with the frequency.The higher the operating frequency of the triboelectric nanogenerator,the smaller the optimal load.The response and recovery process of the self-powered sensor based on triboelectric nanogenerators is also the process of rebalancing the surface charge density on the friction layer.Therefore,the response and recovery speed of selfpowered sensor based on triboelectric nanogenerators is closely related to the charge accumulation speed of the triboelectric nanogenerator.We obtained the relationship between the working frequency of the triboelectric nanogenerator and its performance.By increasing the working frequency of the triboelectric nanogenerator-based selfpowered sensor,we succeeded increasing its response and recovery speed.The experimental results show that for the self-powered ammonia sensor using silver and nylon as the friction layer,when the working frequency is increased from 3.6 to 10.1Hz,the response time is reduced from 31.5 seconds to 12.2 seconds,and the recovery time is reduced from 29.7 seconds to 12.8 seconds.Second.At the same time,the working frequency of the device has little effect on its sensitivity.The relationship between the working frequency of the triboelectric nanogenerator and its performance obtained in this work can supply guidance for the design and different application of triboelectric nanogenerators in the future,and supply a feasible solution for improving the response and recovery time of self-powered sensors based on triboelectric nanogenerators. |
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