Enhanced electrical and energy harvesting performances of lead-free BMT modified BNT piezoelectric ceramics

Figures & data

Figure 1. X-ray diffraction patterns of the mixed (1-x)BNT-xBMT calcined powders with 2θ = 20–80°.

Table 1. Physical property, Microstructure, and XRD parameters of the (1-x)BNT-xBMT ceramics analysis by SmartLab Studio II

x	Density (g/cm^3)	Grain size (µm)	Crystal system	Unit cell volume (Å^3)	a (Å)	rA (Å)	rB (Å)	Tolerance factor (t)
0	6.13	3.00	Rhombohedral	58.61	3.8844	1.3150	0.6050	0.9552
0.05	6.15	3.41	Rhombohedral	58.80	3.8886	1.3148	0.6079	0.9537
0.10	6.21	4.27	Rhombohedral	58.95	3.8919	1.3145	0.6108	0.9532
0.15	6.28	4.47	Cubic	59.24	3.8982	1.3143	0.6136	0.9509
0.20	6.30	5.28	Cubic	59.42	3.9022	1.3140	0.6165	0.9494

Figure 2. Plots of density value as a function of sintering temperature (1100–1200°C) of the (1-x)BNT-xBMT ceramics.

Figure 3. X-ray diffraction patterns of the (1-x)BNT-xBMT ceramics with 2θ = 20–80°.

Figure 4. X-ray diffraction patterns of the (1-x)BNT-xBMT ceramics where x = 0–0.20 with 2θ = 20–80°, 39–41°, and 2θ = 45–48°.

Figure 5. Plots of (a) unit cell volume and tolerance factor (t) values as a function of the BMT content, and (b) the r_A and r_B as a function of the BMT content of the (1-x)BNT-xBMT ceramics.

Figure 6. Raman spectra of the (1-x)BNT-xBMT ceramics measured at room temperature (RT) in the wavenumber range of 100–1400 cm⁻¹.

Table 2. Microstructure, dielectric, ferroelectric, and electric field-induced strain properties of the (1-x)BNT-xBMT ceramics

x	Tm (°C)	εmax (@1 kHz)	δA (K)	Pmax (µC/cm^2)	Pr (µC/cm^2)	Ec (kV/cm)	ΔP (µC/cm^2)	Smax (%)	Sneg (%)	d*33 (kV/cm)
0	328	3158	73.95	12.31	7.54	34.54	0.61	0.06	−0.020	86
0.05	341	2386	78.13	27.90	23.84	34.41	19.55	0.10	−0.005	143
0.10	347	2345	87.66	12.28	5.07	16.22	10.82	0.08	−0.004	114
0.15	349	1965	91.23	12.24	4.42	14.62	10.96	0.07	−0.003	100
0.20	354	2080	94.96	10.72	3.33	12.03	11.05	0.05	−0.003	72

Note: ΔP = P_max – P_r (@125°C and the maximum electric field)

Figure 7. SEM micrographs with as sintered surfaces of the (1-x)BNT-xBMT ceramics where (a) x = 0, (b) x = 0.05, (c) x = 0.10, (d) x = 0.15, (e) x = 0.20, and (f) grain size as a function of BMT content.

Figure 8. Temperature dependence of the dielectric constant (ε_r) and dielectric loss (tan δ) of the (1-x)BNT-xBMT ceramics measured at various frequencies from 1–500 kHz where (a) x = 0, (b) x = 0.05, (c) x = 0.10, (d) x = 0.15 (e) x = 0.20, and (f) plot of T_m and ε_max values as a function of BMT content (inset: δ_A as a function of the BMT content).

Figure 9. Polarization-electric field (P-E) hysteresis loop and current-electric field (I-E) data of the (1-x)BNT-xBMT ceramics, measured at 50 kV/cm and a frequency of 1 Hz where (a) x = 0, (b) x = 0.05, (c) x = 0.10,(d) x = 0.15, (e) x = 0.20, and (f) plot of P_r and E_c values as a function of BMT content.

Figure 10. Temperature dependence on polarization-electric field (P-E) hysteresis loops of the (1-x)BNT-xBMT ceramics where x = 0–0.20, measured under an electric field of 50 kV/cm and a frequency of 1 Hz.

Table 3. Energy storage density, piezoelectric, and energy harvesting properties of the (1-x)BNT-xBMT ceramics

x	W^a (J/cm^3)	η^a (%)	W^b (J/cm^3)	η^b (%)	W^c (J/cm^3)	η^c (%)	d33 (pC/N)	g33 (x10^−3 Vm/N)	FoM (pm^2/N)
0	0.07	4.36	0.09	10.23	0.13	12.11	89	13.82	1.23
0.05	0.11	8.52	0.24	21.54	0.37	25.79	159	26.29	4.18
0.10	0.13	33.51	0.18	57.54	0.30	54.89	115	20.23	2.33
0.15	0.14	41.10	0.19	62.11	0.31	53.87	98	18.42	1.80
0.20	0.15	47.63	0.20	63.92	0.30	53.21	83	16.44	1.37

^aThe data obtained at RT and electric field of 50 kV/cm.

^bThe data obtained at 125°C and electric field of 50 kV/cm.

^cThe data obtained at 125°C and the maximum electric field.

Figure 11. Plots of (a) W_rec as a function of temperature @ E = 50 kV, (b) η as a function of temperature @ E = 50 kV, (c) W_rec @ 125°C as a function of the electric field (until breakdown strength reached), and (d) W_rec @ 125°C as a function of BMT content and measured under E = 50 kV and E= E_max of the (1-x)BNT-xBMT ceramics.

Figure 12. Bipolar strain-electric field (S-E) data of the (1-x)BNT-xBMT ceramics, measured under electric field of 70 kV/cm and a frequency of 0.1 Hz where (a) x = 0, (b) x = 0.05, (c) x = 0.10,(d) x = 0.15, (e) x = 0.20, and (f) plot of S_max and d*₃₃ values as a function of BMT content.

Figure 13. Plots of low-field d₃₃ and g₃₃ values as a function of BMT content of the (1-x)BNT-xBMT ceramics (the inset shows: FoM as a function of BMT content).

Figure 14. Plots of magnetization (M) and magnetic field (H) of the (1-x)BNT-xBMT ceramics, measured at RT and under the magnetic field of −10 kOe ≤ H ≤ 10 kOe, where (a) x = 0, (b) x = 0.05, (c) x = 0.10,(d) x = 0.15, and (e) x = 0.20.