Enhanced dielectric properties and energy storage performance of K0.5Na0.5NbO3-based lead-free ceramics via entropy modulation

This is the authors' abstract. We don't add key points for this paper.

Entropy modulation was introduced into K 0.5 Na 0.5 NbO 3 (KNN)-based ceramics to improve dielectric energy-storage performance under moderate electric fields. KNN-LCITT ceramics were prepared by a conventional solid-state reaction method, and their phase structure, microstructure, dielectric response, impedance behavior, and energy-storage properties were systematically investigated. Compositions with x ≤ 0.16 retained a predominantly KNN-based perovskite structure, whereas secondary phases emerged at x ≥ 0.24. Multicomponent modification reduced the average grain size to 0.34–0.44 μm and enhanced the grain-boundary blocking effect. The x = 0.16 composition exhibited ε r = 1275 and tanδ = 0.067 at 1 kHz with weak frequency dependence. At an applied electric field of 70 kV/cm, it achieved W rec = 0.63 J/cm³ and η = 59.33%, demonstrating the effectiveness of appropriate entropy-mediated compositional regulation in improving the dielectric and energy-storage performance of KNN-based ceramics.