Achieving High Dielectric Constant, High Breakdown Strength, and High Efficiency in a Linear Polymethyl Methacrylate Composite for Energy Storage

Electrostatic capacitors are widely used due to their relatively high voltage, high power density, and high reliability. However, its energy density is very low and unable to meet the growing demand. Moreover, it is usually difficult for a single material to satisfy high dielectric constant, high breakdown strength, and high efficiency simultaneously. Herein, we reported an all-organic composite by using linear polymethyl methacrylate (PMMA) as the matrix. The film was fabricated through a scalable solution casting method for industrial application. Due to good compatibility between the PMMA matrix and poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)), the composite exhibit improved high dielectric constant, enhanced breakdown strength, and maintain excellent energy storage efficiency. After introducing a proper proportion of ferroelectric P(VDF-HFP), a high energy density of 4.43 J/cm3 could be reached, while that of pristine PMMA is only 1.82 J/cm3. Moreover, the efficiency of P-15 is still maintained at 83.4% even under 4500 kV/cm, and the decline of efficiency is very low (5.3% from 500 kV/cm to 4500 kV/cm). This work provides a case to enhance the energy density of PMMA based all-organic polymer composite.