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

The MnO2-doped 0.955NaNbO3-0.045La(Nb1/3Mg2/3)O3 ceramics were prepared through conventional method, effects of MnO2 amount on dielectric property, phase transition behavior and energy storage performance were studied. The introduction of MnO2 could obviously improve sintering performance and effectively stabilize anti-ferroelectric phase, accompanying with the variation of phase transition temperature. An enhanced recoverable energy storage density of 2.63 J/cm3 with efficiency of 66.8% was obtained at room temperature when 1.5% MnO2 was applied. This specimen also demonstrated attractive thermal stability in energy storage during 30-90 oC. In addition, the coexistence of positive and negative electrocaloric effect was observed due to the emergence of anti-ferroelectric phase. And the thermal hysteresis phenomenon was attractive to enhance dielectric and energy storage properties. This will contribute to the promotion of NaNbO3-based lead-free dielectric capacitors.