Development of lead-free materials for piezoelectric energy harvesting

Abstract

Mechanical energy harvesting from ambient vibrations is an attractive renewable source of energy for various applications. Prior research was solely based on lead-containing materials which are detrimental to the environment and health. Therefore, lead-free materials are becoming more attractive for harvesting applications. The present work is focused on the development of lead-free piezoelectric materials based on solid solution having composition (KNa)NbO 3 -xABO 3 , (where A = Li, and B = Nb; x = 0, 5, 5.5, 6, and 6.5 wt%). The solid solutions of the above ceramics were prepared by using solid-state reaction method. The X-ray diffraction spectra exhibited single phase formation and good crystallinity with LiNbO 3 addition up to x = 6.5 wt%. Dielectric studies reveal that the composition with LiNbO 3 = 6.5 wt% exhibits superior properties suitable for piezoelectric energy harvesting applications. The nanoscale piezoelectric data obtained with piezoresponse force microscopy provide a direct evidence of strong piezoelectricity with LN doping. The best piezoelectric properties are obtained for the composition K 0.5 Na 0.5 NbO 3 -6.5%LiNbO 3 .

Energy harvesting: an integrated view of materials, devices and applications

“…Since PZT contains lead that might have potential health issues, there is a strong drive to investigate alternative materials. Rai et al [95] discuss finding lead-free materials, with one example being shown in (figure 39). Attempts have been made to produce efficient lead-free piezoelectric materials.…”

“…Single-phase formation and good crystallinity with LiNbO 3 addition up to x = 6.5 wt% were reported. Dielectric studies reveal that the composition with LiNbO 3 = 6.5 wt% exhibits properties suitable for piezoelectric energy-harvesting applications [95].…”

Bulk micromachined energy harvesters employing (K, Na)NbO3thin film

“…However, this harvester was fabricated merely by cutting mechanically the Si wafer on which the KNN film was deposited. A practical application of the KNN film to the micromachined structure has not been reported yet [8,9]. In this study, a lead-free KNN-based energy harvester was fabricated using bulk micromachining and verified experimentally.…”

Micro-Energy Harvesters Integrated with a Quatrefoil-Shaped Proof Mass Suspended by Multiple (K,Na)NbO3Beams

“…18,19) However, a practical application of the KNN film to the micromachined structure has not been adequately reported. [18][19][20] In this study, a fully micromachined energy harvester employing the KNN film and nonlinear feature of the clamped-clamped beam was fabricated and evaluated.…”