Ultrahigh current density and fatigue stability in flexible energy harvester by designing delivery paths

Abstract

Flexible piezoelectric energy harvesters that efficiently convert mechanical energy into electrical energy have been extensively studied due to their great application potential in low-power wearable electronics and self-powered sensors. However, the low current output and poor thermal fatigue resistance severely restrict their practical applications. Here, we propose a new strategy to simultaneously improve the current density and thermal conductivity of the flexible piezocomposites (PCs) by designing delivery paths. High-quality (Ba0·85Ca0.15) (Ti0·90Zr0.10)O3/copper nanorods/polydimethylsiloxane (BCZT/Cu NRs/PDMS) PCs with a novel co-chained structure prepared using a well-suited technique of dielectrophoresis were reported for the first time. The BCZT particles and Cu NRs aligned in same chains throughout PDMS matrix results in an efficient delivery path both for induced charge transfer and heat dissipation, thus leading to ultrahigh current density (4.7 μA/cm2) and thermal conductivity (0.31 W/(m · K)). Further, a faster charging speed and a dramatically fatigue stability were realized in the co-chained PCs. Our work is expected to provide a potential solution for simultaneously enhancing current density and heat dissipation for a variety of composites in the field of flexible energy harvesting.