Space Charge‐Electron Transmission for Enhancing High‐Temperature Piezoelectricity in BF‐Based Ceramics

Abstract Bismuth ferrite (BF)‐based piezoceramics with enhanced high‐temperature piezoelectric performance are critical for next‐generation, environmentally benign electronic devices targeting applications in extreme environments. However, reconciling the inherent trade‐off between superior piezoelectric coefficients and thermal stability remains a fundamental challenge. In this study, a synergistic strategy combining space‐charge‐limited conduction and electron conduction (SCLC‐ELC) is developed, in which Ga 3+ (corresponding to ELC) is incorporated into a BF‐based matrix containing A‐site cation vacancies (corresponding to SCLC). Phase‐field simulations reveal that this transmission modulation enhances the polarization response by reducing the Landau barriers, while stabilising the coexistence of macro‐ and micro‐domains across a broad temperature range. Consequently, the resultant material demonstrates exceptional piezoelectric performance ( d 33 ∼ 205 pC/N) and thermal stability (310 ± 13% pC/N, 100−415 °C). Systematic characterisation of the domain structure confirms that the coexistence of the stabilised dual‐scale domain is the principal contributor to the enhanced piezoelectric response. In situ electric‐field crystal structure analysis reveals unidirectional evolution to a single phase, verifying the stable existence and irreversible formation of the polar configuration. This synergistic strategy represents a novel design paradigm for enhancing the high‐temperature piezoelectric performance of BF‐based ceramics.