The preparation of MnO2-doped NaNbO3-based lead-free ceramics with enhanced energy storage performance and attractive electrocaloric effect

Abstract

Abstract MnO2-doped 0.955NaNbO3-0.045La(Nb1/3Mg2/3)O3 ceramics were prepared through a conventional method. The effects of MnO2 amount on the dielectric property, and the phase transition behavior and energy storage performance were studied. The introduction of MnO2 can obviously improve sintering performance and effectively stabilize anti-ferroelectric phase, accompanied with the variation of phase transition temperature. An enhanced recoverable energy storage density of 2.63 J·cm−3 with efficiency of 66.8% was obtained at RT when 1.5% MnO2 was applied. This sample also demonstrated attractive thermal stability in energy storage from 30 °C–90 °C. In addition, the coexistence of positive and negative electrocaloric effect was observed due to the emergence of anti-ferroelectric phase. A further advantage of the thermal hysteresis phenomenon possesses abilities to enhance dielectric and energy storage properties. This will contribute to the promotion of NaNbO3-based lead-free dielectric capacitors.