Ultrahigh-rate supercapacitors based on eletrochemically reduced graphene oxide for ac line-filtering

TLDR

The rapid growth of multifunction portable electronics demands compact, efficient, and long‑lasting circuits, yet line‑powered devices rely on bulky aluminum electrolytic capacitors to filter AC ripples from DC buses. The study aims to replace these bulky capacitors with more compact alternatives to improve future electronic devices. The authors fabricated a double‑layer capacitor using three‑dimensional interpenetrating graphene electrodes produced by electrochemical reduction of graphene oxide (ErGO‑DLC). At 120 Hz, the ErGO‑DLC achieved a −84° phase angle, 283 µF cm⁻² specific capacitance, and a 1.35 ms RC time constant, demonstrating its suitability to replace AECs in 120‑Hz filtering.

Abstract

The recent boom in multifunction portable electronic equipments requires the development of compact and miniaturized electronic circuits with high efficiencies, low costs and long lasting time. For the operation of most line-powered electronics, alternating current (ac) line-filters are used to attenuate the leftover ac ripples on direct current (dc) voltage busses. Today, aluminum electrolytic capacitors (AECs) are widely applied for this purpose. However, they are usually the largest components in electronic circuits. Replacing AECs by more compact capacitors will have an immense impact on future electronic devices. Here, we report a double-layer capacitor based on three-dimensional (3D) interpenetrating graphene electrodes fabricated by electrochemical reduction of graphene oxide (ErGO-DLC). At 120-hertz, the ErGO-DLC exhibited a phase angle of −84 degrees, a specific capacitance of 283 microfaradays per centimeter square and a resistor-capacitor (RC) time constant of 1.35 milliseconds, making it capable of replacing AECs for the application of 120-hertz filtering.