Curved Architected Triboelectric Metamaterials: Auxeticity‐Enabled Enhanced Figure‐of‐Merit

Abstract

Triboelectric generators are integrated into curved architected materials to realize triboelectric metamaterials that simultaneously harvest electricity from wasted mechanical energy and perform mechanical energy absorption. Novel triboelectric mechanical metamaterials (TMMs) of distance‐changing, angle‐changing, and mixed modes are designed, fabricated, and tested under a cyclic compressive load. The open‐circuit voltage and short‐circuit current of lightweight TMMs are found to be as high as 40 V and 10 nA. The introduced TMMs can effectively harvest energy under loadings from two distinctive directions. A theoretical model for predicting the energy harvesting properties of TMMs is developed, and the role of auxeticity on the energy harvesting figure‐of‐merit (FOMes) is elicited. The introduced TMMs exhibit enhanced FOMes enabled by a decrease in their negative Poisson's ratio and an increase in their resilience. The FOMes of curved architected TMMs surpasses by more than 16 times the FOMes of triboelectric materials with conventional architectures (i.e., triangular, quadrilateral, and hexagonal cell topologies). An intelligent skateboard with integrated TMMs is fabricated as a proof of concept to demonstrate motion sensing, shock‐absorbing, and energy harvesting functionalities of multimodal triboelectric metamaterials. The introduced design strategy for triboelectric metamaterials unlocks their applications in self‐powered and self‐monitoring sports equipment, smart soft robots, and large‐scale energy harvesters.