Enhanced energy density at low operating field strength of laminated multicomponent polymer-based composites via regulation of electrical displacement

Dielectric polymer-based composites have demonstrated enormous promise in the applications of electrostatic film capacitors due to their exceptional insulating characteristics. However, the achievement of great energy-storage density (U _e) is always difficult in linear dielectric polymer-based composites for operation at weak field strength due to the low permittivity (ϵ _r) and electric displacement difference (D _max − D _rem) values. Here, a tri-layered configuration of multicomponent polymeric films is proposed. The outer layers of the tri-layered composite are linear dielectric polymethyl methacrylate (PMMA), and the inner layer is a nonlinear polymer incorporating a low number of polydopamine-modified barium titanate particles (BT@PDA). An increased ϵ _r of 8.9@1 kHz is achieved in the designed composite featuring only 2 wt% BT@PDA fillers, equivalent to 234% of the PMMA (∼3.8@1 kHz) matrix. An improved U _e of 9.3 J cm⁻³ at 340 MV m⁻¹ is endowed in the designed film, implying an enormous ∼343% increment of the energy storage compared to the benchmark biaxially oriented polypropylene (∼2.1 J cm⁻³ at 300 MV m⁻¹). All these advantages present a practical strategy for supplying linear dielectric polymer-based composites with anticipative capacitive energy-storage properties for operation at weak field strengths.