Flexible piezoelectric energy harvester based on graphene macro-film electrode enabled by exploiting auxetic mechanical property

The flexible piezoelectric energy harvester (f-PEH) has attracted wide attention due to its potential use for autonomous wearable electronics. However, the amount of power from the existing f-PEH is insufficient for practical applications. Hence, this paper aims at developing a novel electrode material, i.e. graphene macro-films (GAMF), to improve the electrical output performance of the f-PEH. Theoretical results indicate that the f-PEH of GAMF with absolute value of greater negative Poisson's ratio (NPR) and a larger Young's modulus shows better electrical output performance. Demonstrative experiment shows that the voltage output performance of f-PEH can be significantly increased by improving its mechanical properties. The load characteristic test shows the maximum output power of the optimized sample is 296.86 nW. The feasibility of the sample in practical application is also verified by the stability test. In addition, the energy harvesting circuit is designed to demonstrate high efficiency of this novel f-PEH, which was able to lighten LEDs after the motivation of finger bending to charge the capacitor. This paper indicates that the f-PEH based on the NPR GAMF has great application potential in the wearable field.

Automated summary

This paper introduces a novel electrode material, graphene macro-films (GAMF), for improving the electrical output performance of the flexible piezoelectric energy harvester (f-PEH). The theoretical analysis and experimental results show that the f-PEH with GAMF having a greater negative Poisson's ratio and a larger Young's modulus exhibits better electrical output performance. The feasibility of the optimized sample in practical application is verified through load characteristic tests and stability tests.