High energy density and efficiency of laminated polymeric blend-based composites via introducing ultra-low content micrometer sheets

Polymeric blend-based composites are promising for dielectric capacitor due to the excellent dielectric and energy storage properties. However, the electric displacement difference (D_max-D_r) and dielectric constant (ε_r) of the polymeric blend-based composites are incompatible, which further limits the improvement of the available energy densities (U_e). In this study, we propose the solution-processable laminated polymeric blend-based composites to address this challenge. The concurrent enhancement in D_max-D_r, ε_r, U_e and charge-discharge efficiency (η) of designed composites is attributed to the synergistic interaction between macroscopic layered interfaces and microscopic interfaces. The laminated polymeric blend-based composites were fabricated by utilizing a blend of 50 wt% poly(vinylidene difluoride)-hexafluoropropylene (P(VDF-HFP)) and linear poly(methyl methacrylate) (PMMA) as the outer layer and P(VDF-HFP)/PMMA incorporated with an ultralow content alumina-modified strontium titanate plates (SrTiO₃@Al₂O₃) the inner layer. As a result, laminated polymeric blend-based composite with the optimized content (0.5 vol%) delivers a maximum U_e of 14.36 J/cm³ due to highest D_max-D_r of 7.96 μC/cm², ε_r of 6.12 (1 kHz), E_b of 400 MV/m, and η of 76.6 %, outperforms those of representative polymer blend-based composites. Specially, laminated polymeric blend-based composite also exhibits the excellent energy storage reliability of different areas. Therefore, this contribution provides a viable approach to promote polymeric blend-based composites for capacitive energy storage.