High-Entropy-Nanofibers Enhanced Polymer Nanocomposites for High-Performance Energy Storage

摘要

Polymer composite dielectrics capable of high energy density, high efficiency,and high-temperature stability are in high demand for application invarious electronic vehicles and power systems. A major challenge, however,is the reasonable design of high-performance nanofillers that are beneficialto the polarization and breakdown strength simultaneously. Here, highentropy-induced ceramic nanofibers with a stable Bi_2Ti_2O_7-type pyrochlorephase are developed as effective nanofillers to enhance the energy storageperformance of polyetherimide (PEI) composites. Benefiting from the linearpyrochlore phase, refined grain size, and increased amorphous fraction ofthe high-entropy nanofillers, the resultant PEI composites exhibit significantlyimproved energy storage performance over a wide temperature rangeof 25–150 ℃. Notably, a high energy density of 6.46 J cm~(?3) under an electricfield of 590 MV m~(?1) is achieved at 150 ℃, which outperforms most of thereported PEI composites. This study provides a guideline for the developmentof dielectric fillers with tunable dielectric properties and microstructures, thuspromoting the development of high-performance polymer composites.