A novel lead-free NaNbO3-based relaxation ferroelectric ceramics for energy storage application

In order to stay away from fossil fuels and avoid the inherent unpredictability of clean energy, it is necessary to combine energy collection technology with energy storage equipment. In energy storage devices, batteries, electrochemical supercapacitors and electrostatic capacitors can be found everywhere. Currently, dielectric energy storage capacitors with high power density and high energy storage efficiency are required to meet the requirements of portable electronic devices. The materials used for dielectric energy storage capacitors mainly include ceramics, polymers, glass ceramics, ceramic/polymer composites and so on. Compared with other dielectric energy storage materials, dielectric ceramics have the advantages of large dielectric constant, low dielectric loss, medium breakdown electric field, good temperature stability, and good fatigue resistance. Therefore, dielectric energy storage ceramics have good application prospects. As a typical relaxation ferroelectric material in dielectric ceramic materials, it has the characteristics of electric field induced phase transition. It can be applied to portable electronic devices with high energy density and high power density. However, from the perspective of current technological development, it is still challenging to develop a lead-free relaxation ferroelectric material with appropriate power density and breakdown field strength. In this paper, based on the NaNbO3, (1-X)Na0.97Sm0.01NbO3-X(Sr0.6Na0.2Bi0.2)(Sn0.6Ti0.4)O-3 were prepared using traditional solid-state sintering. It can be observed that the surface grains of the materials are tightly arranged and have low porosity by SEM. At room temperature and at a frequency of 10 Hz, the hysteresis loops of different samples were measured by the ferroelectric tester. Adjust the external electric field to 410 kV/cm, When x=0.06, the component exhibits the maximum effective energy storage density W-rec is 2.62 J/cm(3) and the maximum energy storage efficiency n is 84.31% At a frequency of 10 Hz, adjust the temperature to 30-80 degrees C, test the corresponding bipolar P-E curves, the prepared relaxation ferroelectric ceramic materials still maintains a good and no obvious deformation hysteresis loop, and the energy storage efficiency fluctuates by less than 10%. At a temperature of 25 degrees C, adjust the frequencies to 10-250 Hz, test the corresponding bipolar P-E curves, the prepared relaxation ferroelectric ceramic materials still maintains a good hysteresis loop without obvious deformation, and the energy storage efficiency fluctuates by less than 6%, so the materials have good stability of temperature and frequency. As mentioned above, the prepared ceramics have good prospects in energy storage applications.