Excellent energy storage performance of multi-alternating-layer structured PMMA/PVDF dielectric composite at high-temperature

Polymer dielectric capacitors have high power density and are an integral component of electronic and power device. Currently, the limited energy density restricts their further application. In this research, a novel method was designed to optimize performance of PMMA/PVDF composite via an alternating stacked multi-layer structure. And, the five-alternating-layer of PVDF-PMMA-PVDF-PMMA-PVDF (F-A-F-A-F) composite has excellent dielectric properties, for instance, a better dielectric constant (4.52@1 kHz) and a low dielectric loss (0.034@1 kHz). The discharge energy density (U_e) of it is significantly larger than that of PMMA and PVDF. Particularly, the U_e of F-A-F-A-F composite is increased by 83.0 % (from 4.71 J/cm³ to 8.62 J/cm³) with charging-discharging efficiency of 60 % at 80 °C. Moreover, the F-A-F-A-F composite achieves an excellent stability after 40,000 cycles. This composite has a wide range of potential applications in the field of traditional dielectric capacitor due to its good energy storage performance and cycle stability.