Engineering metal–organic framework towards suppressed leakage current in polymer nanocomposites†

The development of high-performance power electronics is constrained by the lack of polymer dielectrics capable of operating under extreme conditions. Conventional dielectrics face significant challenges at high temperatures and electric fields due to increased leakage currents and dielectric loss. In this work, we introduce zeolitic imidazolate framework (ZIF-11) as a filler for polyetherimide (PEI), showcasing its dual functionality in suppressing both ionic and electronic conduction. The strong electrostatic interactions between ZIF-11 and the PEI matrix reduce free volume, inhibiting ionic species' mobility, while the high electron affinity of ZIF-11 introduces multiple traps for electronic charge carriers, significantly lowering electronic conduction. Leveraging these synergistic effects, the composite achieves an order-of-magnitude reduction in leakage current with ≤1 wt% ZIF-11. It maintains >80% efficiency at 625 MV m⁻¹ and 150 °C, achieving an energy density of 5.44 J cm⁻³—a 1.38-fold improvement over unfilled PEI and surpassing current dielectric polymers and polymer nanocomposites. This scalable strategy demonstrates the transformative potential of engineering MOF-based fillers in designing advanced polymer dielectrics for next-generation power electronics.