All-organic siloxane-strengthening polymer dielectrics for high-temperature capacitive energy storage in harsh-environment electronics†

Dielectric polymer films often suffer from poor energy-storage levels in harsh-environment electronic devices, circuits and systems. In this work, a molecular engineering strategy is described to synergistically achieve high mechanical strength (321 MPa), breakdown strength (726 MV m⁻¹) and energy density/efficiency (6.5 J cm⁻³ at η = 90%) at 150 °C in fabricated all-organic siloxane-strengthening polyamide films, whose comprehensive performances present obvious preponderance in the existing polymer dielectrics. It is demonstrated that the coexistence of a strong hydrogen bond, large energy gap and siloxane unit, which specifically reduces interchain interactions in constraint space rather than causing traditionally limitless reduction, synergistically strengthens energy-storage and mechanical performances. Meanwhile, upon confronting harsher partial corona discharge in some particular application scenarios, the copolymerized siloxane unit can generate a SiO₂-like structure in situ to effectively resist direct and persistent corona discharge, thereby maintaining high energy-storage levels. This work explores a valuable all-organic design route to synergistically enhance the high-temperature energy storage performance, mechanical strength and partial corona discharge resistance ability of polymer dielectrics, which also presents large-scale production superiority in fabricating high-quality polymer dielectrics for harsh-environment applications in electronics.