Polymer Nanocomposites with Ultrahigh Energy Density and High Discharge Efficiency by Modulating their Nanostructures in Three Dimensions

Manipulating microstructures of composites in three dimensions has been a long standing challenge. An approach is proposed and demonstrated to fabricate artificial nanocomposites by controlling the 3D distribution and orientation of oxide nanoparticles in a polymer matrix. In addition to possessing much enhanced mechanical properties, these nanocomposites can sustain extremely high voltages up to ≈10 kV, exhibiting high dielectric breakdown strength and low leakage current. These nanocomposites show great promise in resolving the paradox between dielectric constant and breakdown strength, leading to ultrahigh electrical energy density (over 2000% higher than that of the bench‐mark polymer dielectrics) and discharge efficiency. This approach opens up a new avenue for the design and modulation of nanocomposites. It is adaptable to the roll‐to‐roll fabrication process and could be employed as a general technique for the mass production of composites with intricate nanostructures, which is otherwise not possible using conventional polymer processing techniques. Artificial nanocomposites fabricated by controlling the 3D distribution and orientation of oxide nanoparticles in a polymer matrix enable much enhanced mechanical and electrical properties along the out‐of‐plane direction, exhibiting high dielectric breakdown strength and low leakage current. These microstructured nanocomposites show great promise in resolving the paradox between dielectric constants and breakdown strength, leading to ultrahigh electrical energy density and discharge efficiency.