0.9BaTiO3-0.1Bi(Mg1/2Ti1/2)O3 Ferroelectric Thin Films:Preparation and Energy Storage
Dielectric thin film,one of the materials of which storage energy in the form of electrostatic field via dielectric polarization,can be widely used in electric equipment,due to their high power density and high charge/discharge efficiency.Currently,the dielectric energy storage films perform lower energy density and weak temperature stability.In this work,0.9BaTiO3-0.1Bi(Mg1/2Ti1/2)O3(0.9BT-0.1BMT)ferroelectric thin films were prepared via a Sol-Gel method on Pt/Ti/SiO2/Si substrates and annealed in the range of 700-900℃to realize high energy storage density and wide-temperature stability by introducing BMT.The effect of annealing temperature on phase composition and microstructure was investigated.The results show that denseness of thin films reduce obviously when the annealing temperature is over 750℃and their grain size increases gradually with the increase of treatment temperature.Additionally,the thin films annealed at 750℃display optimized comprehensive feature:room-temperature dielectric constant of～399,loss tangent of～5.79%at 1 kHz,and ∆C/C25℃ratio only within±13.9%.Meanwhile,relaxor value,γ≈1.96 calculated according to Currie-Weiss law consolidates that the thin films possess obvious relaxor characteristics.Results of energy storage shows that the max value of Wrec is～51.9 J/cm3,and the τ0.9 is below 15 μs at pulse charge measure.Moreover,results of temperature stability measurement show Wrec>20 J/cm3,η>65%(1600 kV/cm)and τ0.9<7.2 μs from room temperature to 200℃,demonstrating that the film still exists high and stable energy storage under high temperature.Therefore,the ferroelectric thin film 0.9BT-0.1BMT prepared in this work has a promising applications in energy storage under high temperature environment.
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