Study of ferroelectric and piezoelectric response of heat-treated surfactant-based BaTiO₃ nanopowder for high energy capacitors

Barium titanate (BaTiO₃) nanopowder was synthesized by the alkoxide-hydroxide sol–gel process in an inert (N₂) atmosphere. The effect of surfactant sodium dodecyl sulfate (SDS) concentration on the dispersion of BaTiO₃ powder was studied at different sintering temperatures, under microwave heating. The phase and structural analysis revealed that the addition of surfactant did not affect the phase transformation of barium titanate. The best outcome was obtained in the case of 0.5 % surfactant-based BaTiO₃. At 1100 °C sintering temperature, 0.5 % surfactant-based BaTiO₃ exhibited a maximum density of 97.7 %, dielectric constant of 9488, the leading parameters of breakdown strength as 3.12 kV/cm, the figure of merit as 9.98 × 10³, and the piezoelectric constant (d₃₃) as 153 pC/N. Moreover, the energy density of 86 kJ/m³ with an energy efficiency of 27.43 % was attained at 1100 °C. For pure BaTiO₃ nanopowder, the energy density and the energy efficiency were found as 66.85 kJ/m³ and 50.42 % at 1250 °C, respectively.