High-entropy strategies boosting dielectric temperature stability in (Na_0.4K_0.1Bi_0.5)TiO₃ ceramics

Utilizing a high-entropy strategy, we propose a novel approach for synthesizing (Na_0.4K_0.1Bi_0.5)TiO₃ (NKBT)-based ceramics endowed with exceptional dielectric stability at elevated temperatures. The high-entropy effect induces a random tilt in the oxygen octahedra of NKBT ceramics, leading to a broad dielectric response characterized by diffuse phase transitions. By weakening the dielectric abnormal peak at T_s of BNT, the dielectric stability of high-entropy NKBT ceramics is significantly enhanced. Notably, at 100 kHz, the temperature stability range of (Na_0.4K_0.1Bi_0.5)(Ti_0.65Zr_0.1Sn_0.15Hf_0.1)O₃, synthesized through the traditional solid reaction method, reaches an impressive 311°C, surpassing undoped NKBT by 257%. This significant enhancement underscores the feasibility of our high-entropy strategy in improving dielectric performance. Our work demonstrates a straightforward and cost-effective method for significantly improving the dielectric temperature stability of NKBT ceramics.