High-temperature and high-dielectric capacitor material in ultra-wide stable temperature zone and preparation method thereof

The invention discloses a high-temperature and high-dielectric capacitor material in an ultra-wide stable temperature zone and a preparation method thereof. The chemical composition of the capacitor material is 0.99[(1-x)Bi0.5Na0.5TiO3-xNaNbO3]-0.01Sr0.8Na0.4Nb2O6, and x is equal to 0.25. The preparation process of the capacitor material comprises the following steps of firstly drying original powder, and then weighing the original powder, and performing primary ball milling on the original material, pre-sintering, performing secondary ball milling, performing isostatic compaction, and finally sintering in a high-temperature furnace in an air atmosphere. The dielectric constant epsilon' of the capacitor material at the room temperature is 1250, and with the dielectric constant at the room temperature as the reference, the temperature zone corresponding to the fluctuation of 15% of the dielectric constant on the reference is -90 DEG C to 383 DEG C, and the temperature zone corresponding to the dielectric loss