Configuration-entropy effects on BiFeO-BaTiO relaxor ferroelectric ceramics for high-density energy storage

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-05, Vol.12 (2), p.11995-128
• Main Authors: Montecillo, Rhys, Chen, Cheng-Sao, Feng, Kuei-Chih, Chien, R. R, Chen, Pin-Yi, Tu, Chi-Shun
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d4ta00921e

High energy-storage capability and electric breakdown strength are critical elements in next-generation pulse-power dielectric capacitors. In this report, perovskite (Bi 0.7 Ba 0.3 ) 1− x Na x (Fe 0.7 Ti 0.3 ) 1− x Ta x O 3 relaxor ferroelectric ceramics ( x = 0-0.3) were tailored in terms of configuration entropy from a medium entropy of 1.21 R to a high entropy of 2.07 R to improve energy storage. The integration of paraelectric NaTaO 3 into BiFeO 3 -BaTiO 3 results in breaking of the long-range order and formation of multiple lattice distortions toward relaxor ferroelectric characteristics. Excellent recoverable energy densities of 9.6 J cm −3 and 10.3 J cm −3 with efficiencies of 77% and 68% at 350 kV cm −1 and 550 kV cm −1 (at 10 Hz) were achieved for x = 0.15 and 0.20, respectively. Wide operating frequency (1-100 Hz) and temperature (25 °C-150 °C) stabilities were confirmed at 300 kV cm −1 . Grain boundaries and nanoclusters play critical roles as electric barriers to suppress charge mobility and increase electric breakdown strength. This study presents a promising scheme to utilize high-configuration entropy BiFeO 3 -BaTiO 3 -based ceramics for high energy-density electrostatic capacitors. A high-configuration entropy results in the formation of grain boundaries and nanoclusters, which act as barriers for enhancing breakdown strength and energy-storage capability.