▎ 摘　　要

Rapid advances in flexible and wearable electronics have enhanced demand for electrochemical capacitors (ECs) with fast frequency responses and supernal electrochemical supercapacitive properties. Here, we report the development of a fiber-shaped supercapacitor device based on Ar plasma-treated, highly electrically conductive reduced graphene oxide (rGO) fibers. Typical rGO-based, fiber-shaped ECs exhibit ultrafast frequency responses (phase angle = -81.1 degrees), a short resistor-capacitor (RC) time constant (0.471 ms at 120 Hz), and excellent cycle stability. The superior performance of our device relative to most advanced carbon-based ECs is promising for alternating current line filtering performance.