Thermally-stable high energy storage performances and large electrocaloric effect over a broad temperature span in lead-free BCZT ceramic

Abstract

Thermally-stable recovered energy density and significant electrocaloric temperature change over a broad temperature span in BCZT ceramic elaborated by low-temperature hydrothermal processing.

Thermal-stability of the enhanced piezoelectric, energy storage and electrocaloric properties of a lead-free BCZT ceramic

“…This nature can be related to the ferroelectric clusters or residual polar nanoregions (PNR), which can be attributed to relaxor behaviour. 11 Correspondingly, the temperature-dependence of the current density-electric eld (J-E) curves of BCZT ceramic are displayed in Fig. 3b.…”

“…27 On heating, their intensities steadily decrease, indicating the approach to the ferroelectric-to-paraelectric phase transition. 11,13,17 Above the Curie temperature, in the cubic paraelectric phase, they disappear and only two disorderactivated broad peaks centred at 260 and 514 cm À1 are observed. It is worth noting that the A 1g octahedral breathing mode at $800 cm À1 persisting in the whole range of the temperatures is not related with the structural distortion of the ferroelectric phase but results instead from the local distortions, caused either by the presence of B-sites occupied by cations of different sizes (Zr 4+ /Ti 4+ ) or from donor A-site substitutions.…”

“…Lead-based piezoceramics such as lead zirconium titanate (PbZr x Ti 1Àx O 3 , PZT) systems have aroused substantial interest due to their outstanding piezoelectric, electrocaloric and energy storage performances. [1][2][3][4] However, due to the environmental and human concerns caused by their toxicity, the integration of lead-based materials in future applications will be restricted. 3,5,6 In 2009, Liu and Ren reported a Ba 0.85 Ca 0.15 Zr 0.10 Ti 0.90 O 3 (BCZT) material with excellent electrical and piezoelectric properties as a revolutionary discovery in the eld of ferroelectrics, which can substitute the Pb-based materials.…”

“…3,10 For this purpose, BCZT ferroelectric relaxor can full this necessity due to its diffuse ferroelectric transition. [11][12][13] Hanani et al 11 reported the thermal-stability of the energy storage and electrocaloric properties of BCZT ceramic elaborated by low-temperature hydrothermal processing, and found a small energy storage variation (ESV) of 12.7% between 27 and 127 C, alongside with enhanced recovered energy storage (W rec ) of 414.1 mJ cm À3 at 107 C. In addition, Puli et al 14 investigated the energy storage performances in (1 À x)BZT-xBCT (x ¼ 0.10, 0.15, 0.20) system and observed improved W rec and high energy storage efficiency (h) of 680 mJ cm À3 and 72.8%, respectively, at x ¼ 0.15 under 170 kV cm À1 . Besides, Cai et al 15 studied the effect of grain size on the dielectric, ferroelectric, piezoelectric and energy storage performances, and observed that the piezoelectric coefficient (d 33 ) gradually increases with the grain size increasing, however, despite the enhanced h, low W rec and modest ESV were reported.…”

“…13,[16][17][18][19][20][21] Zhou et al 18 investigated the electrocaloric effect (ECE) in lead-free (1 À x)BZT-xBCT system under a moderate electric eld of 28 kV cm À1 and reported high ECE response of 0.56 K at x ¼ 0.6. In addition, Ben Abdessalem et al 22 studied the electrocaloric effect (ECE) in BCZT indirectly using Maxwell relation under 30 kV cm À1 and obtained DT ¼ 0.565 K around T C ¼ 119 C. Besides, Hanani et al 11 reported a signicant electrocaloric temperature change (DT) of 1.479 K with remarkable refrigerant capacity (RC) of 140.33 J kg À1 , and a high coefficient of performance (COP ¼ input power/output cooling power) 23 of 6.29 under 55 kV cm À1 .…”