Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics

The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment. However, the need for high heat transfer rates in thermal harvesting systems is a longstanding obstacle for their practical application. In this work, we construct thermally conductive networks in Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(Zr95Ti5)1−yO3 (lead magnesium niobate–lead antimony–manganese–lead zirconate titanate: PMN–PMS–PZT) ceramics to improve heat transfer and enhance their ferroelectric properties by use of a thermally conductive AlN additive dispersed in the ceramic matrix. The ferroelectric properties, pyroelectric coefficient and thermal conductivity of the PMN–PMS–PZT: AlN composite materials are influenced by the AlN content as a result of the formation of random bridges or thermally conductive networks for phonon transfer in the ceramic matrix, thereby leading to high heat transfer. For a PMN–PMS–PZT composite with a 0.2 wt% AlN content, the ferroelectric properties, pyroelectric coefficient and thermal conductivity are shown to be enhanced owing to the improved crystallinity and density, and the relative permittivity is also reduced, which results in optimized pyroelectric figure of merits. This combination of materials property enhancements is shown to be beneficial for high performance pyroelectric materials in devices for energy harvesting applications.