Energy conversion from heat to electricity by highly reversible phase-transforming ferroelectrics

TL;DR

This paper introduces a reversible phase-transforming ferroelectric material capable of efficiently converting low-grade waste heat into electricity, demonstrating stable, cyclic energy harvesting suitable for practical applications like powering LEDs.

Contribution

The study presents a novel ferroelectric material with high reversibility, low hysteresis, and stable energy harvesting performance over many cycles, advancing heat-to-electricity conversion technology.

Findings

Stable electricity generation of 15μA in cycles

Consistent 6μA/cm² current density near 100°C

Device can power a LED directly from waste heat

Abstract

Searching for performant multiferroic materials attracts general research interests in energy science as they have been increasingly exploited as the conversion media among thermal, electric, magnetic and mechanical energies by using their temperature-dependent ferroic properties. Here we report a material development strategy that guides us to discover a reversible phase-transforming ferroelectric material exhibiting enduring energy harvesting from small temperature differences. The material satisfies the crystallographic compatibility condition between polar and nonpolar phases, which shows only 2.5C thermal hysteresis and high figure of merit. It stably generates 15uA electricity in consecutive thermodynamic cycles in absence of any bias fields. We demonstrate our device to consistently generate 6uA/cm2 current density near 100C over 540 complete phase transformation cycles without any electric and functional degradation. The energy conversion device can light up a LED directly without attaching an external power source. This promising material candidate brings the low-grade waste heat harvesting closer to a practical realization, e.g. small temperature fluctuations around the water boiling point can be considered as a clean energy source.