The preparation of MnO <sub>2</sub> -doped NaNbO <sub>3</sub> -based lead-free ceramics with enhanced energy storage performance and attractive electrocaloric effect
Tao Zhang, Tomoaki Karaki, Tadashi Fujii
Abstract
Abstract MnO 2 -doped 0.955NaNbO 3 -0.045La(Nb 1/3 Mg 2/3 )O 3 ceramics were prepared through a conventional method. The effects of MnO 2 amount on the dielectric property, and the phase transition behavior and energy storage performance were studied. The introduction of MnO 2 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% MnO 2 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 NaNbO 3 -based lead-free dielectric capacitors.