Huge Energy Storage Capacity Driven by Self-Assembling Insulated Networks through Layer Periodicity Modulation

To achieve further optimization of dielectric capacitors for modern advanced electronic devices and power systems, the overall improvement of the energy storage density and energy storage efficiency remains a great challenge. We implemented a strategy that leverages the self-assembled insulating network structures of the Bi-O layer unit to simultaneously optimize both the energy storage density and efficiency. Using the introduction of relaxation ferroelectric block of SrTiO₃ with trace Mn elements, the periodic tunability of the perovskite layer of the Bi₄Ti₃O₁₂ structure is realized through reducing the interlayer coupling force, from 3 to 8 layers, which induces the random distribution of the Bi-O layer, resulting in the insulating network structure. The structure of the Bi-O network was clearly observed using spherical aberration-corrected transmission electron microscope, which effectively improves the multidimensional insulating properties of the film, thus greatly improving the high voltage resistance, while maintaining high polarization disorder. The simultaneous enhancement of spontaneous polarization (80 μC·cm^-2) and breakdown strength (5.1 MV·cm^-1) in the present thin films leads to a <i>W</i>_rec of 140 Joules per cubic centimeter and efficiencies as high as ∼76%. The proposed strategy provides valuable design ideas for high-performance dielectrics.