基于振动波调制的低频段高效摩擦纳米发电机的机理及制备研究

Triboelectric nanogenerator (TENG) becomes the promising candidate of power supply for mobile devices, owing to the simple preparation, high instantaneous power, as well as easily multi-layer integration. Accompanying the reducing of vibration frequency, the reported TENGs have the problem of output performance degradation when harvesting the vibration energy under 5 Hz. In this project, Maxwell’s displacement current and V-Q-x physical model are employed for deducing the optimal parameters of vibration energy, with which the output performance of TENG does not decline with the decreasing of vibration frequency. The low-frequency vibration energy with irregular frequency and amplitude will be modulated with optimal parameters based on the deduced results. The optimized TENG with Silk-fibroin friction layer will have a stable and high output performance when harvesting the modulated low-frequency vibration energy. Consequently, the high-efficiency TENG without the low frequency restriction can be fabricated. In addition, the triboelectric effect applied in high sensitivity self-powered acceleration sensor will be studied based on the deduced relationship between vibration acceleration and output voltage. The project will effectively enhance the output performance when TENG harvests the low-frequency vibration energy, and accelerate the application of TENG in the supply of new electronic devices and self-driven system.

摩擦纳米发电机以制备简便、高瞬时功率、便于多层集成等优势，成为快速发展的移动电子设备的备用供电技术。已报道的摩擦纳米发电机在采集5 Hz以下的振动能量时，输出性能存在着随振动频率降低而下降的问题。为了解决低频段的输出性能瓶颈，本项目根据麦克斯韦位移电流原理和V-Q-x物理模型，理论推导输出性能不随振动频率降低而下降的振动波最优参数。并根据推导结果，将环境中频幅无规则的振动波调制成具有或接近最优参数的振动能量。采用优化的Silk-fibroin摩擦层摩擦纳米发电机采集经过调制的振动能量时，具有稳定的高输出性能，进而实现突破低频制约的高效摩擦纳米发电机的制备。另外，根据理论推导振动加速度与输出电压的对应关系，提出了摩擦起电效应在高灵敏度自供电加速度传感器方面的应用研究。项目的开展将有效提高摩擦纳米发电机采集低频振动能量的输出性能，加快其在新型电子器件供电及自供电系统中的应用进程。

摩擦纳米发电机（TENG）以高瞬时功率、能量采集范围广、造价低廉等诸多显著优势，自提出以来，在环境能量采集、自供电传感等应用领域发展迅速。本项目针对摩擦发电机采集超低频（<5 Hz）振动能量时，输出性能随振动频率降低而下降的难题，开展基于振动波调制的低频段高效摩擦纳米发电机的机理及制备研究。首先根据麦克斯韦位移电流原理和V-Q-x 物理模型分析低频段输出性能下降的根本原因，并建立TENG采集低频振动能量的理论模型，分析获得TENG输出性能下降的根本原因是摩擦层接触-分离时间τ，而不是振动波形的频率。并以此设计了一种带有振动波调制的摩擦纳米发电机，通过优化振动波调制装置结构和摩擦层材料，TENG在采集0.1 ~ 10 Hz的环境振动能量时，输出电压峰值始终保持在230 V左右，从理论和实验角度，实现了TENG对低频振动能量的高效稳定地采集。同时，本项目在固液TENG能量采集方面的研究，实现了液滴表面能和重力势能的采集。. 在自供电传感技术方面，首先理论推导了振动加速度与输出电压的对应关系，提出了TENG自供电加速度传感器的电压-电荷-加速度（V-Q-a）理论模型，并将其应用范围扩展到自由落体、正弦运动等多种应用场景。以此理论为指导，研制的自供电加速度传感器灵敏度高达20.4 V/(m/s2)，瞬时输出功率371.8 mW/m2，在可穿戴式人体运动监测、物体振动强度检测等方面具有潜在的应用前景。另外，本项目申请获得的“一种低阻尼电容式加速度传感器及其制备方法”专利，并将其成功转化到相关芯片企业，促进了低阻尼高性能加速度传感器的应用进程。