The need for efficient energy utilization is driving research into ways to harvest ubiquitous waste heat. Here, we explore pyroelectric energy conversion from low-grade thermal sources that exploits strong field- and temperature-induced polarization susceptibilities in the relaxor ferroelectric 0.68Pb(Mg_1/3Nb_2/3)O₃–0.32PbTiO₃. Electric-field-driven enhancement of the pyroelectric response (as large as −550 μC m⁻² K⁻¹) and suppression of the dielectric response (by 72%) yield substantial figures of merit for pyroelectric energy conversion. Field- and temperature-dependent pyroelectric measurements highlight the role of polarization rotation and field-induced polarization in mediating these effects. Solid-state, thin-film devices that convert low-grade heat into electrical energy are demonstrated using pyroelectric Ericsson cycles, and optimized to yield maximum energy density, power density and efficiency of 1.06 J cm⁻³, 526 W cm⁻³ and 19% of Carnot, respectively; the highest values reported to date and equivalent to the performance of a thermoelectric with an effective ZT ≈ 1.16 for a temperature change of 10 K. Our findings suggest that pyroelectric devices may be competitive with thermoelectric devices for low-grade thermal harvesting.

对有效能源利用的需求正在推动对收集无处不在的废热的方法的研究。在这里，我们研究了低级热源的热电能量转换，该热源利用了弛豫铁电0.68Pb（Mg _1/3 Nb _2/3）O ₃ –0.32PbTiO _3中强磁场和温度引起的极化磁化率。电场驱动的增强热电响应的（大至-550  μ C M ^-2  ķ ^-1）和介电响应的抑制（降低72％）可为热电能量转换带来可观的品质因数。与场和温度有关的热电测量结果突出了极化旋转和场感应极化在介导这些效应中的作用。固态，薄膜器件，其将低等级的热量转化为电能的使用热电爱立信周期证实的，和优化以获得最大的能量密度，功率密度和1.06Ĵ厘米效率^-3，526W¯¯厘米^-3和19卡诺的百分比分别；最高值报告的日期，并等同于有效ZT热电性能 ≈ 1.16对于10 K的温度变化。我们的发现表明，热电设备在低等级热收集方面可能与热电设备竞争。