Electric-Field-Enhanced Ultrafast Electrochemical Capacitors for Miniaturized Line Filtering

Line filtering plays a pivotal role in AC-DC conversion by exploiting capacitors' fast energy storage characteristics. Under the requirement of fast responses, line-filtering capacitors are currently mainly electrolytic capacitors. However, their low specific capacitance and cumbersome volume limit the circuit miniaturization.
Electrochemical capacitors theoretically possess 3 orders of magnitude higher specific capacitance than electrolytic capacitors. However, its slow ionic kinetics render the failure to respond to line power signals^1,2. Here, we propose an electric field enhancement strategy to promote ion migration³. The series resistance at 120 Hz is reduced to 39 mW cm², comparable to the electrolytic capacitors. Meanwhile, when the phase angle at 120 Hz is -80°, the areal specific capacitance reaches 5.2 mF cm^-2, two orders of magnitude higher than conventional electrolytic capacitors. This research sheds new light on the design of electrochemical capacitors for line filtering and promotes their practical application in integrated circuits.



References
1 Miller, J. R., Outlaw, R. A. & Holloway, B. C. Graphene Double-Layer Capacitor with ac Line-Filtering Performance. Science 329, 1637-1639 (2010).
2 Han, F. et al. Structurally integrated 3D carbon tube grid-based high-performance filter capacitor. Science 377, 1004-1007 (2022).
3 Hu, Y. et al. Ultralow-resistance electrochemical capacitor for integrable line filtering. Nature 624, 74-79 (2023).