• • Machine learning identified organic fillers with Eg ≈ 5.5 eV and Ea ≈ 4.5 eV, enabling deep electron traps while maintaining insulation, a combination previously unattainable.
• • Composite films achieved an energy density of 5.1 J cm−3 at 250 °C with 90% charge-discharge efficiency, far exceeding BOPP's operational limit of ~105 °C.
• • The fillers suppressed leakage current and delayed avalanche onset, directly improving breakdown strength under practical electrical stresses.
• • Roll-to-roll production yielded kilometer-scale composite films with uniform dispersion, demonstrating scalability for industrial capacitor manufacturing.