“…However, the mechanical properties, and especially the stiffness, of unfilled polysiloxanes are poor. In addition, as most polymers, polysiloxanes are characterized by a low dielectric permittivity [ 16 , 17 , 18 , 19 , 20 ], which is an advantage for some applications, such as insulators, but not for energy storage and energy conversion devices. Either dielectric fillers, such as barium titanate, lead magnesium niobate, lead titanate, zinc oxide and titanium dioxide, or conducting fillers, such as carbon black, carbon nanotubes and graphene oxide, have been tested to increase the dielectric permittivity of polysiloxanes [ 15 , 17 , 18 , 19 ].…”