Structural and dielectric performance study of microencapsulated graphene-reinforced silicone foam elastomer composites

Lightweight and flexible materials with high dielectric constant and low dielectric loss are highly desirable for capacitor energy storage applications. In this study, a new class of microencapsulated graphene-reinforced silicone elastomer foam composite with excellent dielectric properties is presented. The silicone elastomer/graphene composite was prepared through foaming. The interfacial compatibility between silicone elastomer and graphene was enhanced by microencapsulated graphene, with graphene as the core and MF as the shell, through in-situ grafting reactions. The best microencapsulated graphene with a “salt-like” substance was achieved at a dispersing power of 840 W, a ratio of graphene to emulsifier of 1:100, and a mass ratio of graphene to wall material MF of 1:10. The silicone elastomer foam composite with optimized microencapsulated graphene content displays a dielectric constant of 27.26 @1000 Hz ~ 10 MHz with a significantly improved dielectric loss of @1000 Hz ~ 10 MHz, which is 2.45 times greater than the dielectric constant of graphene/silicone elastomer composite. This performance originates from the synergistic effect of micropore and microencapsulated. This interaction reaches its peak when the content of microencapsulated graphene is increased to 2.0 wt%, resulting in a dielectric constant of 48.26. The optimization of high-electric-constant foam composite will have far-reaching impacts on the sustainable energy and will be an important research topic in the near future.