Constructing Topological Vortex Domains in Polar Nano‐Regions Enables High‐Capacitive Energy Storage

Overcoming the polarization-relaxor trade-off in dielectric capacitors remains a critical challenge for achieving simultaneous high energy density (W_rec) and efficiency (η). While conventional polar nano-regions (PNRs) enhance relaxor behavior, their limited dipole vector lengths inevitably suppress polarization strength. Here, the long-standing dilemma is resolved by constructing topological vortex domains (VDs) within PNRs (VPNR) through synergistic disorder engineering and grain size confinement in BiFeO₃-based thin films. Phase-field simulations reveal that the VPNR structure combines ultralow domain-switching energy barriers with minimally reduced polarization vectors under high electric fields, enabling concurrent optimization of relaxor dynamics and polarization strength. Experimental validations via multiscale characterization confirm that the engineered VPNR configuration exhibits balanced polarization characteristics of high maximum polarization and small remanent polarization. The optimized film achieves a breakthrough W_rec of 130 J cm^-3 and η of 80% at 4864 kV cm^-1, surpassing pristine BiFeO₃ by 545% and 400%, respectively. This work establishes a topology-driven paradigm for dielectric energy storage, demonstrating universal potential to decouple polarization-relaxor constraints in next-generation capacitive materials.