Enhanced energy storage performance of BaTi0.97Ca0.03O2.97-based ceramics by doping high-entropy perovskite oxide

To improve the comprehensive energy storage performance of the BaTi 0.97 Ca 0.03 O 2.97 -based ceramics for pulse power capacitors, a typical bismuth-based high entropy compound, Bi(Li 0.2 Y 0.2 Mg 0.2 Ti 0.2 Ta 0.2 )O 3 (BLYMTT) was introduced into 0.9Ba(Ti 0.97 Ca 0.03 )O 3 -0.1Bi 0.55 Na 0.45 TiO 3 (0.9BTC-0.1BNT) matrix. The results indicate that the phase structure transforms from tetragonal phase to pseudo-cubic phase with increasing BLYMTT, and the relaxor ferroelectric behavior are also enhanced. The 0.91(0.9BTC-0.1BNT)-0.09BLYMTT ceramic simultaneously achieves a high energy storage density of 4.89 J/cm 3 and efficiency of 91.2% at electric field of 240 kV/cm. Moreover, the 0.91(0.9BTC-0.1BNT)-0.09BLYMTT ceramic also exhibits superior temperature (30–100 ℃) and frequency (1–100 Hz) stability, as well as the ultrahigh power density of P D ~66.01 MW/cm 3 and rapid discharge rate of t 0.9 ~97 ns at 140 kV/cm, which is of great potential for energy storage application. • HEC substitution improved the comprehensive energy storage performance. • The W rec and ƞ achieved 4.89 J/cm 3 and 91.2%, respectively at x = 0.09. • Tailing the phase structure proportion affects polarization.