Abstract:Dielectric capacitors have the advantages of high power density, fast charge and discharge speed, and long cycle life. Therefore, they have broad application prospects in pulse power weapon equipment, power transmission and transformation engineering, and 5G communications. Polypropylene (PP) is one of the most widely used dielectric materials in commercial applications at present, which has high breakdown strength, low dielectric loss and good processability. Nevertheless, its dielectric constant is relatively low, which makes it hard to increase the energy storage density. This disadvantage greatly limits the applications of PP. The composite or modification based on PP can effectively enhance the energy storage density, thus becoming a hot research topic. This paper reviews the classification and existing problems of dielectric composites in recent years, linking the two synthesis strategies of filler/polymer composites and all-organic composites with the improvement of the energy storage performance of PP, and focuses on the research progress of PP-based dielectric composites from the aspects of inorganic ceramic fillers/PP, conductive fillers/PP, core-shell structured fillers/PP, ternary composites, cross-linking, blending, design of multilayer structure, etc. Finally, the challenges for developing high-performance PP-based dielectric composites and the prospects for future research directions were summarized.

Key words: polypropylene; energy storage; dielectric composites