Anisotropic Semicrystalline Homopolymer Dielectrics for High-Temperature Capacitive Energy Storage.

High-temperature dielectric polymers are in high demand for powering applications in extreme environments. Here, we have developed high-temperature homopolymer dielectrics with anisotropy by leveraging the hierarchical structure in semicrystalline polymers. The lamellae have been aligned parallel to the surface in the dielectric films. This structural arrangement resembles the horizontal alignment of nanosheet fillers in polymer nanocomposites and nanosheet-like lamellae in block copolymers, which has been proven to provide the optimal topological structure for electrical energy storage. The unique ordering of lamellae in our dielectric films endue a significantly increased breakdown strength and a reduced leakage current compared to amorphous films. This novel approach of enhancing the capacitive energy storage properties by controlled orientation of lamellae in homopolymer offers a new perspective for the design of high-temperature polymer dielectrics.