Entropy regulation enhanced superior energy storage density and high temperature stability in lead-free relaxors

The inferior energy storage capability and high temperature reliability of ceramic capacitors are a main factor restrict the further application. In this article, we propose to overcome the above issues through increasing the configuration entropy (triangle S-config). The novel high entropy ceramics (1-x) (Na0.5Bi0.47La0.03)(0.94)Ba0.06TiO3-xCa(0.7)La(0.2)Ti(0.85)Hf(0.15)O(3) were successfully designed and synthesized to enhance comprehensive performance. With the triangle S-config rises from 0.98 R to 1.54 R, the optimum composition exhibits outstanding recoverable energy storage density (W-rec) of 6.21 J/cm(3) under 420 kV/cm and dielectric high temperature stability (triangle C/C-25 degrees C <= +/- 15%, -59-372 degrees C) in accordance with X9R, which can be ascribed to refined grain size, improved bandgap width, inhibited leakage current and interfacial polarization and modified relaxor behavior caused by the improvement of triangle S-config. Interestingly, the high entropy composition was firstly tested fatigue endurance at 150 degrees C and 200 degrees C and shown prominent high temperature reliability. These results provide a new viewpoint for designing high temperature capacitors.