Flexible high-entropy functional ceramics

Functional ceramics, once integrated with flexibility, hold great promise for cutting-edge electronic devices. Unfortunately, functionality and flexibility are inherently exclusive in ceramics: the long-range order of ionic lattices bestows polarization-like properties that accompany brittleness, whereas disorder tolerates bond rotation to generate flexibility with significant loss of performance. Implanting ordered functional motifs within amorphous ceramics, though challenging, may balance this trade-off. Here, the challenge is met through a high-entropy strategy, which allows the initial crystallization of randomly dispersed nanocrystals followed by controlled amorphization of high-entropy compositions to attain a crystalline/amorphous microstructure, yielding a Bi4Ti3O12-based film that can withstand ~180° folding with a bending strain and tensile elongation up to 4.80% and 5.29%, respectively. The crystalline/amorphous structure enables the production of a flexible dielectric capacitor with high permittivity (~35), good temperature stability and durability. This strategy offers research prototypes for customizing the microstructures of functional ceramics, advancing next-generation ceramics with flexibility.