Research On Structure Control And Energy Storage Properties Of PbZrO₃ Based Antiferroelectric Thin Films

Nowadays,the iterative development of high-tech electronic products is changing with each passing day,which also drives the demand for smaller and lighter energy storage components.As a kind of electrical energy storage and conversion device with fast charging and discharging speed and long life,dielectric energy storage capacitors have attracted the attention of researchers,but there are still some problems to be solved in their further development.For example,the high cost of preparation,certain self-discharge rate and low energy storage density and efficiency values have seriously limited the development of dielectric capacitors.It has been shown that improving the breakdown strength and polarization regulation are essential for the improvement of capacitor energy storage performance.In this thesis,Pb Zr O₃（PZO）based antiferroelectric films with typical field-induced phase transition properties are modified by introducing insulating layers to build composite films and ion modification to investigate the effects of different structures and ion doping concentrations on the film performance.The films with optimal performance components were further regulated by annealing temperature to achieve high energy storage performance by adjusting their polarization behavior.Firstly,PZO/MgO composite films and Pb(Zr_（1-x）Li_x)O₃ films were prepared by sol-gel method by selecting MgO and Li⁺as the insulating layer and dopant ion,respectively.It was found that the best performance of the PMP-1 component in the composite films was achieved,and the addition of the insulating layer not only improved the breakdown field strength of the films but also played a role in regulating the polarization behavior,and the P-E loops of the films showed a ferroelectric state transition.Although the breakdown field strength and energy storage density of the film were improved,the efficiency was only 44.01%at the maximum breakdown field strength due to the high polarization loss.On the other hand,the Pb(Zr_0.92Li_0.08)O₃ film with 8%Li⁺concentration has the best performance with improved energy storage density and efficiency,but the breakdown strength is almost unchanged compared to the pure PZO film.To further optimize the breakdown field strength and efficiency of the films,the annealing temperature was chosen to be regulated during the preparation of the films.The results show that the low-temperature annealing introduces the pyrochlore phase,which plays a role in refining the grains and greatly suppresses the polarization loss of the films.the best performance of the PMP-1 composite films and Pb(Zr_0.92Li_0.08)O₃ films was achieved when the annealing temperature was adjusted to550°C.The former obtained an energy storage density of 17.27 J/cm³ and an efficiency of 75.53%in an electric field of 3100 k V/cm,while the latter achieved a breakdown field of 4000 k V/cm and obtained an energy storage density of 29.53 J/cm³ while maintaining a high efficiency of 82.38%.It is worth mentioning that the above films have shown good stability after charge/discharge cycle tests,which also provides a reference for their application in the working environment.