Roll‐to‐Roll Production of High‐Performance All‐Organic Polymer Nanocomposites for High‐Temperature Capacitive Energy Storage

Abstract Dielectric materials with significant performance in high temperatures are highly desired, especially in harsh environments. However, the polymer‐based dielectric films have developed so far, the production scale remains at the state of the lab. Here, an all‐organic strategy is proposed by introducing phenyl‐acid‐based polymer nanodots (PAPD) into Polyetherimide (PEI), achieving high capacitive energy storage properties even at 200 °C and mass production by an industrial continuous roll‐to‐roll process. The abundant hydrogen bonding between PAPD and PEI chains ensures uniform distribution for the enhanced interaction between nanofillers and polymer matrix. Under UV irradiation, the electron‐affinity and band gap of the film are further extended, which impede charge transfer and reduction of conductive loss. A low loading (0.3 wt.%) of PAPD renders the membrane significant improvement in breakdown strength and charge–discharge efficiency. An ultrahigh energy storage density of 5.1 J cm⁻³ with a charge–discharge efficiency of over 90% and charge–discharge cycle stability up to 2 × 10⁴ cycles at 150 °C is observed. Furthermore, a 1000 m long roll of polymeric film is roll‐to‐roll fabricated on an industrial solution‐casting production line and the low cost makes practical commercial scale application possible. Considering the low loading and low cost of nanofiller, this all‐organic design strategy sheds light on the industrial application of high‐temperature dielectric materials.