Multicomponent BNT-Based Ceramics for Dielectric Energy Storage: A Review of Domain Engineering, Lattice-Distortion Regulation, and Processing Strategies

Bismuth sodium titanate (Bi 0.5 Na 0.5 TiO 3 , BNT) is a promising lead-free candidate for pulsed-power dielectric capacitors owing to its maximum polarization. However, its recoverable energy density and efficiency remain constrained by substantial polarization hysteresis, limited electric breakdown strength, and processing-induced defects. This review systematically evaluates multication BNT compositions within the comprehensive framework of multicomponent ceramics. Herein, ideal configurational entropy is treated as a compositional descriptor and an upper-bound estimate, rather than as definitive proof of entropy stabilization or an isolated performance-governing mechanism. The reported energy-storage enhancements are rationalized via experimentally accessible manifestations of compositional complexity: chemical short-range order, local electric and strain fields, lattice distortion, phase and domain heterogeneity, grain refinement, defect chemistry, and electrical homogeneity. Particular attention is devoted to domain engineering, lattice-distortion regulation, and advanced processing routes that synergistically optimize reversible polarization and breakdown strength. Furthermore, this review outlines key criteria required to distinguish genuine entropy-driven contributions from general multicomponent effects and proposes function-oriented, nonequimolar design strategies for future high-performance BNT-based dielectrics.