Research progress in polymer-ceramic nanocomposites for dielectric energy storage applications

Owing to the feature of ultrahigh power density, the dielectric capacitors play an increasingly important role in the field of industrial production, basic scientific research, aerospace, and military industry in recent years. However, the relatively low energy storage density of the dielectric capacitors generally leads to their big sizes, which is difficult to meet the miniaturization requirements of future devices. Polymer-ceramic nanocomposites can combine high permittivity of the ceramic fillers and the excellent breakdown strength of the polymer matrix, thus achieving excellent energy storage performance. At present, developing the polymer-ceramic nanocomposites with high energy storage density is the key to realize the miniaturization goal of dielectric capacitors in the future. The current research progress of polymer-ceramic nanocomposites for energy storage capacitor applications from three perspectives was systematically summarized, including regulation of the nanofillers, optimization of the interfaces, and design of the multilayer composite structure. Notably, the influences of the dimension, size, species, hierarchical structure of the nanofillers, interface optimization methods such as surface modification and core-shell structure construction, as well as multilayer structure design such as sandwich structure and gradient structure on the permittivity, breakdown strength and the energy storage density of the nanocomposites were introduced in detail. Meanwhile, the structure-activity relationships between the microstructure of nanocomposites and their energy storage properties were further analyzed and discussed. Finally, based on the challenges and shortcomings of the current research, the important development directions of this field in the future were proposed, including selecting the new 2D nanofillers, enhancing the energy storage efficiency, employing multimode combined optimization strategy, and constructing the corresponding dielectric capacitors.