Low-temperature Phase Boundary Dispersion Characteristics and Optimization of Electrical Performance in KNLNSx-BAZ Ceramics

Abstract

The piezoelectric properties of KNN-based ceramics have been significantly enhanced near room temperature through the successful construction of a polymorphic phase boundary (PPB). However, in practical applications such as aerospace, polar exploration, and low‑temperature electronic devices, piezoelectric ceramics are often required to maintain stable performance over a wide temperature range. Currently, research on KNN‑based ceramics remains largely focused on phase‑boundary regulation and performance optimization near room temperature, while systematic studies on the stability and electrical performance evolution mechanisms under low‑temperature conditions are still lacking. This gap severely limits the reliable application of these materials in extreme environments. In this work, a 0.96(K0_.48Na_0.52)_0.96Li_0.04(Nb_1-xSb_x)O₃-0.04(Bi_0.5Ag_0.5) ZrO₃ (KNLNS_x-BAZ) ceramic system was designed and fabricated by introducing Sb⁵⁺ ions to substitute the B‑site. The incorporation of Sb⁵⁺ is intended to further regulate phase transition behavior and broaden the phase transition temperature range, thereby constructing a low‑temperature multiphase coexistence structure characterized by a “diffuse phase boundary.” This diffuse phase boundary can effectively suppress abrupt phase structure changes induced by temperature fluctuations, leading to enhanced stability of piezoelectric and dielectric properties at low temperatures. The influence of Sb⁵⁺ doping on the phase structure and low‑temperature electrical properties of KNLNS_x-BAZ ceramics was systematically investigated, providing new insights and experimental foundations for the development of KNN‑based piezoelectric ceramics with excellent low‑temperature stability.