Dielectric, ferroelectric, and energy conversion properties of a KNN/P(VDF-TrFE) composite film

A (Ba0.94Ca0.06)(Ti0.95Zr0.05)O3 ceramic sheet doping to improve the inverse piezoelectric effect of the poly (vinylidene fluoride‐trifluoroethylene)‐based composite film

“…Besides, tan δ of composite increases first and then decreases with the increase of frequency. At low frequencies, tan δ depends on the conductance loss that decreases as frequency increases, while at high frequencies, tan δ mainly originates from the polarization loss that increases as frequency increases 41 …”

“…At low frequencies, tan δ depends on the conductance loss that decreases as frequency increases, while at high frequencies, tan δ mainly originates from the polarization loss that increases as frequency increases. 41 To clarify the piezoelectric effect of this BCTZ/P (VDF-TrFE) composite, inverse piezoelectric effect and electrostriction effect should be identified which independent of each other. Inverse piezoelectric effect is predominant in piezoelectric materials under relatively low electric field, and can be used to calculate the piezoelectric strain constant (d 33 ).…”

Graphene doping to enhance the mechanical energy conversion performances of GR/KNN/P(VDF-TrFE) flexible piezoelectric sensors

“…The KNN ceramic powder was synthesized using Na 2 CO 3 , K 2 CO 3 , and Nb 2 O 5 mixture in a muffle furnace at a high temperature, which referred to the traditional solid-state reaction method reported by our previous work. 10 Specifically, the three raw materials of K 2 CO 3 , Nb 2 O 5 , and Na 2 CO 3 in the oven were first dried to completely remove the moisture that was absorbed from the air and then weighed according to the chemical equation (K 2 CO 3 + Na 2 CO 3 + 2Na 2 O 5 → 4K 0.5 Na 0.5 NbO 3 + 2CO 2 ). The weighed raw materials were taken in a nylon ball mill jar equipped with zirconium balls, and then an appropriate amount of anhydrous ethanol was added as a ball milling medium, and ball milled for 24 h. Next, the obtained mixed slurry was dried, then heated to 950 °C at a constant ramp rate of 5 °C min −1 , and held at this temperature for 2 h. Finally, the steps of ball milling, mortar milling, and sieving (200 mesh) were performed to obtain finer KNN powder for use.…”

“…8 Nevertheless, the piezoelectric performance of pure P(VDF-TrFE) still suffers from the obvious deficiency, i.e., its d 33 (the d 33 of pure P(VDF-TrFE) is only 22 pC N À1 in our previous work) is generally lower than that of inorganic piezoelectric ceramics. 9,10 More recently, many researchers have made efforts to promote the piezoelectricity of the pure P(VDF-TrFE), and accordingly, some effective ways, including grafting, blending, compounding, etc., have been proposed. Among them, one of the widely used methods is to dope different kinds of functional fillers into the polymers to increase the b-phase content in the crystal region of P(VDF-TrFE).…”

“…, its d 33 (the d 33 of pure P(VDF-TrFE) is only 22 pC N −1 in our previous work) is generally lower than that of inorganic piezoelectric ceramics. 9,10…”