Topological Engineering of Filler Distributions in Dielectric Composites to Boost High‐Temperature Capacitive Energy Storage Performance

ABSTRACT Polymer dielectrics, essential for thin‐film capacitors, face challenges of excessive leakage current at elevated temperatures. By incorporating the fillers with high electron affinity, they can function as effective electron‐trapping centers; however, their spatial distribution also affects both electron transfer and breakdown pathways. Herein, we fabricate five‐layered composite films using poly(m‐phenylenetisophthalamide) (PMIA) as the matrix and ZrO ₂ as the filler. By optimizing the filler distribution as a Type ∇ pattern, with doping ratios of 1.0, 0.5, 0, 0.5, and 1.0 wt.% (totaling 0.6 wt.%) across five layers, a built‐in electric field ( E _built‐in ) forms between adjacent layers due to non‐uniform electric field distribution. In addition to the intrinsic trapping effect of fillers, this E _built‐in opposes the external electric field near the terminal electrodes, generating a repelling force that further inhibits electron transfer. Consequently, leakage current is reduced by two orders of magnitude compared to the PMIA film. The optimal layered film achieves a maximum discharge energy density ( U _max ) of 14.01 J cm ⁻³ at 150°C and 12.75 J cm ⁻³ at 200°C, while retaining 8.89 ⁻ and 5.68 J cm ⁻³ at 90% efficiency, respectively. This highlights a promising horizon for developing high‐temperature dielectric composites via topological engineering of filler distribution.