High-power density pyroelectric energy harvesters incorporating switchable liquid-based thermal interfaces

Pyroelectric thermal energy harvesters are intriguing alternatives to thermoelectric devices due to their high thermodynamic efficiency and reduced heat sink requirements. We report a concept for pyroelectric energy harvesters that utilize liquid-based switchable thermal interfaces to achieve thermodynamic cycling frequencies and hence high-power densities. Pyroelectric energy harvesting in thin films of 56/44 P(VDF-TrFE) copolymer is demonstrated at thermodynamic cycle frequencies of the order of 1 Hz and material-level power densities of the order of 100 mW/cm³. The present work demonstrates the viability of high-power density pyroelectric thermal energy harvesters based on liquid-based switchable interfaces and identifies a need for optimized electrode arrays to maximize their potential.