Flexible hybrid piezo/triboelectric energy harvester with high power density workable at elevated temperatures

Abstract

Eco-friendly energy harvesters with high output for effectively harvesting mechanical energy over a broad temperature range are highly desirable. Here, a lead-free, flexible, and efficient hybrid energy harvester was demonstrated by the combination of a single electrode triboelectric energy harvester (TEH) and an interdigital electrode piezoelectric energy harvester (PEH), which are based on a 0–3 composite of high temperature BiFeO₃–BaTiO₃ (BF–BT) piezoelectric ceramic particles and polyimide (PI) matrix. With an appropriate external connection, the hybrid piezo–triboelectric energy harvester (P–TEH) generates an open-circuit voltage and a short-circuit current of 175 V and 600 nA, respectively, together with high power density of 4.1 mW cm⁻³. This work demonstrates that the combination of the interdigital electrode PEH with TEH can enable high electrical output due to minimum internal interference between the two energy harvesting parts. Of particular significance is that the flexible P–TEH shows great high temperature stability up to 200 °C with an open-circuit voltage of 150 V and a short-circuit current of 560 nA, exhibiting excellent potential for using at high temperature.