High-entropy strategy applied to dielectric energy storage

Electrostatic capacitors store electric energy through the separation of opposite charges by a layer of dielectric material sandwiched between a pair of metal electrodes. Such energy storage devices feature fast charge/discharge rates and high power densities, rendering them indispensable components in modern electronics and power apparatus, such as electric drive vehicles and pulsed power systems. One of the remaining technical bottleneck issues of electrostatic capacitors lies in the limited energy storage density that is usually orders of magnitude lower than the electrochemical counterparts, falling short of the need for compact-size electronics and electrical apparatus. For instance, electrostatic capacitors occupy $\sim 35$ vol% in the power control unit of electric drive vehicles, $\sim 40$ vol% in medical defibrillators, and $\sim 50$ vol% in power transmission converters.