Yingchun Su

1 Introduction Dielectric capacitors exhibit ultrahigh power density and ultrafast charge-discharge rates, playing an indispensable role in pulsed power technologies. Currently, BOPP polymer dielectrics represent the state-of-the-art in commercial high-energy-density capacitors.[1] They exhibit an exceptionally high breakdown strength (BDS) of up to 600 MV m−1, delivering a recoverable energy density (Wrec) of 3–5 J cm−3 and an efficiency (η) exceeding 95 % at room temperature.

1 Introduction The rapid development of emerging electronics (such as wearable electronics, the Internet of Things, and soft robotics) imposes the demand for efficient, lightweight, flexible, and portable power sources.[1, 2] Currently widely-used batteries are considered ineffective due to their bulky form factor and heavy weight, their need for frequent recharging/replacement and critical raw materials (such as Li and Co), and the increasing global concern of battery waste.