Lead-free relaxor-ferroelectric thin films for energy harvesting from low-grade waste-heat

Abstract

One of the ways to mitigate the world energy crisis is to harvest clean and green energy from waste-heat, which is abundant, ubiquitous, and free. Energy harvesting of this waste-heat is one of the most encouraging methods to capture freely accessible electrical energy. Ferroelectric materials can be used to harvest energy for low power electronic devices, as they exhibit switchable polarization, excellent piezoelectric and pyroelectric properties. The most important characteristic of ferroelectric materials, in the context of energy harvesting, is their ability to generate electric power from a time-dependent temperature change. In this work, we grew highly c-axis oriented heterostructures of BaZr0.2Ti0.8O3 (barium zirconium titanate, BZT)/Ba0.7Ca0.3TiO3 (barium calcium titanate, BCT) on SrRuO3 (strontium ruthenate, SRO) and deposited on SrTiO3 (strontium titanate, STO) single crystalline substrate using pulsed laser deposition (PLD) technique. We investigated the structural, electrical, dielectric, and pyroelectric properties of the above-mentioned fabricated heterostructures. The wide range of θ–2θ X-ray diffraction (XRD) patterns only shows (00l) reflection peaks of heterostructures and the substrate which confirmed that the films are highly c-axis oriented. We are also capable to convert the low-grade waste-heat into electrical energy by measuring various temperature-dependent ferroelectric hysteresis loops of our nanostructure films via pyroelectric Ericsson cycles and the structures show an energy conversion density ~ 10,970 kJ/m3 per cycle. These devices exhibit a large pyroelectric current density of ~ 25 mA/m2 with 11.8 °C of temperature fluctuation and the corresponding pyroelectric coefficient of 3425 μC/m2K. Our research findings suggest that these lead-free relaxor-ferroelectric heterostructures might be the potential candidates to harvest electrical energy from waste low-grade thermal energy.

Pyroelectric Nanogenerator Based on an SbSI–TiO2 Nanocomposite

“…A rectangular-shaped transient characteristic of pyroelectric current was observed ( Figure 5 b,d) when the triangular temperature waveform was applied to the SbSI–TiO 2 nanogenerator. Such behavior is well documented in the literature for other pyroelectric materials, e.g., PVDF–TiO 2 composite [ 45 ], PVDF–ZnO nanocomposite [ 63 ], Bi 0.5 Na 0.5 TiO 3 –P(VDF–TrFE) nanocomposite [ 64 ], P(VDF–TrFE) [ 65 ], PbTiO 3 –P(VDF–TrFE) [ 66 ], LiNbO 3 –polypropylene [ 67 ], CeO 2 -doped Na 0.5 Bi 0.5 TiO 3 ceramics [ 68 ], BaZr 0.2 Ti 0.8 O 3 /Ba 0.7 Ca 0.3 TiO 3 heterostructures [ 69 ], and CdS nanorods [ 47 ]. This proves that the measured electric response of the SbSI–TiO 2 nanocomposite was due to the true pyroelectric effect.…”

Energy Harvesting Technology by Converting Waste Heat Energy from Automobiles

“…According to the results of Amrit P. Sharma and his colleagues, these lead-free relaxor-ferroelectric hetero structures might be promising candidates for harvesting electrical energy from waste low-grade thermal energy [6]. HaicaiLv In comparison to other reported flexible TEDs, the proposed system that manufactured S-TED produces a high output power of 749.19 nW under a vertical gradient of 30 K using just three pairs of p-n couple, equal to a high output power of 416.22 nW cm-2.…”

“…This can be accomplished by making nanoscale highlights, for example, particles, wires, or interfaces in mass semiconductor materials. Notwithstanding, the assembling cycles of nanomaterials are as yet testing [6]. Figure 2 shows the proposed model of the project.…”

Energy Conversion from Heat to Electricity by Highly Reversible Phase-Transforming Ferroelectrics

“…As the nanofabrication technologies flourished, the Olsen cycles have been realized in thin-film devices [9][10][11][12]. The applied bias voltage between two isoelectric processes of the Ericsson cycle is reduced to 2 and 8 V for thin-film pyroelectric capacitors [12,13]. A main problem of these latest devices is the confusion regarding where the electricity comes from.…”

“…This is one of the obstacles preventing pyroelectric energy conversion from achieving broad commercialization. Recent advances in innovative thermal management [12,14] and exquisite nanodevices [10,13,15] have pushed the device performance toward its current limit, that is, up to several hundreds of nanoamperes [10][11][12][13]15]. However, the ambient thermal fluctuations in nature can never reach the heating and cooling frequencies modeled in some reported devices [12,13].…”