| With the advancement of science and technology,wearable devices have ushered in tremendous progress,and have gradually become an indispensable part of people’s lives.The reduction of the size of wearable devices and the integration of functions have brought great convenience to life,but the increase of functions requires more energy support,and the reduction of the size has brought restrictions on the design of energy storage systems,leading to the need for wearable devices.Frequent charging brings inconvenience in use.Vibration energy harvesting during human walking can convert walking vibration into electrical energy output,providing a rich source of energy for wearable devices.Considering the low frequency,broadband and multi-directional characteristics of walking vibration,this article abandons the traditional electromagnetic power generation method and chooses to use the friction nano power generation technology.Because its power generation characteristics are related to the polarization of the material medium,the friction nano power generator is used in It also has high-efficiency power generation characteristics at low frequencies.After discussing the possibility of using liquid as a friction material,this paper analyzes the sensitivity of liquid materials to vibration using the liquid surface wave height formula,and proves that using liquid metal as a friction material has a good response to the low-frequency characteristics of walking vibration.Therefore,the design concept not only utilizes the low-frequency characteristics of friction nano-power generation,but also brings better low-frequency response capabilities to the device due to the use of liquid substances as friction materials,which further meets the characteristics of human walking vibration.In the design part of the generator,this article has launched a research on the selection of friction materials.After a series of comparisons on the stability and power generation capacity of friction materials,the choice of liquid metal and solid friction materials was finally determined.In addition,the innovative proposal will use the freestanding power generation mode to further improve the power generation capacity of the equipment and reduce the complexity of the design.Based on the research results,this paper also intro-duces the bistable structural design on the basis of the design,hoping to further improve the low-frequency performance of the equipment,and conducts a bistable modeling anal-ysis combined with the design specifications to verify the bistable characteristics of the design,and Completed the complete assembly and initial experiments.On this basis,this paper proposes a new type of independent layered friction nanogenerator based on liquid metal.This article describes the experimental content in detail.In the multi-amplitude sweep frequency experiment,the working frequency band of the device can completely cover the range of 3-18Hz,and it has good broadband characteristics.In addition,under the condition that the peak-to-peak value of external excitation is 16mm,its peak output voltage and output current can reach 265.4V and 26.5μA.It is measured after the optimal load is connected,and the optimal power density of the device can be reached 33000m W/m~3.We also conducted a capacitor charging experiment,in which a 10μF capacitor can be charged to 6.46V in 60s.In the actual environment wear experiment,not only the influence of walking speed and device placement on the output performance is explored,but also100 small LED lights can be lit during normal walking.A liquid-metal-based freestanding triboelectric generator proposed in this paper can adapt to the vibration characteristics of walking vibration on the basis of wearable characteristics,and provides a new idea for energy harvesting of wearable devices. |
