We demonstrate a capacitor with high energy densities, low energy losses, fast discharge times, and high temperature stabilities, based on Pb(0.97)Y(0.02)[(Zr(0.6)Sn(0.4))(0.925)Ti(0.075)]O3 (PYZST) antiferroelectric thin-films. PYZST thin-films exhibited a high recoverable energy density of U(reco) = 21.0 J/cm(3) with a high energy-storage efficiency of η = 91.9% under an electric field of 1300 kV/cm, providing faster microsecond discharge times than those of commercial polypropylene capacitors. Moreover, PYZST thin-films exhibited high temperature stabilities with regard to their energy-storage properties over temperatures ranging from room temperature to 100 °C and also exhibited strong charge-discharge fatigue endurance up to 1 × 10(7) cycles.

Lead-free Mn-doped (K0.5, Na0.5)NbO3 (KNN) thin films were fabricated by the chemical solution deposition method. The addition of small concentration of Mn dopant effectively reduced the leakage current density and enhanced the piezoelectric properties of the films. The leakage current density of 0.5 mol. % Mn-doped KNN film showed the lowest value of ∼10-7 A/cm2 at 10 V compared to the films with other doping concentrations and the piezoelectric d33 and e31 coefficients of this film were ∼90 pm/V and −8.5 C/m2, respectively. The maximum power and power density of the lead-free thin film-based vibrational energy harvesting device were 3.62 μW and 1800 μW/cm3 at the resonance frequency of 132 Hz and the acceleration of 1.0 G. The results prove that the 0.5 mol. % Mn-doped KNN film is an attractive candidate transducer layer for the piezoelectric MEMS energy harvesting device applications with a small volume and a long-lasting power source.

No abstract