Enhanced Energy Storage Performances of Ceramics Enabled by Local Lattice Disorder Based on High‐Entropy Strategy

ABSTRACT With the depletion of energy resources and the vigorous development of renewable energy technologies, the demand for efficient energy storage technologies has become increasingly urgent. Dielectric ceramics feature ultrafast charge–discharge speed, but low energy density and inferior efficiency hinder device miniaturization. This work adopted a high‐entropy strategy to optimize the energy storage performance of 0.5(Bi 0.5 Na 0.5 ). This work adopts TiO 3 ‐0.5(La 0.1 Mg 0.2 Sr 0.6 )TiO 3 ‐based ceramics. The x = 0.17 sample achieves an ultrahigh breakdown strength of 650 kV/cm and a large energy density of 9.42 J cm −3 , whereas the x = 0.19 ceramic delivers an energy efficiency of ∼85%. Heterovalent ion doping disrupts long‐range ferroelectric ordering and generates disordered lattice structures with varied octahedral tilting and polarization states, thereby promoting polar nanoregions (PNRs) and reducing remnant polarization. Transmission electron microscopy (TEM) and piezoresponse force microscope (PFM) verify the existence of PNRs and local lattice disorder regions (LDRs), and phase‐field simulations confirm that abundant grain boundaries suppress electric breakdown propagation. This work offers a reliable strategy to design dielectrics with superior energy density and breakdown resistance.