Fast-response supercapacitors with graphitic ordered mesoporous carbons and carbon nanotubes for AC line filtering

Abstract

Replacing the bulky aluminum electrolytic capacitors (AECs) used extensively in AC line filtering with a compact supercapacitor would contribute greatly to the miniaturization of electronic devices. However, the supercapacitors developed for AC line filtering have limited application voltages of ≤∼20 V. To extend the range of application voltages, it is essential to design carbon electrode materials with a suitable pore structure. This paper reports that graphitic ordered mesoporous carbon (GOMC) can be used as an electrode material in supercapacitors for AC line filtering applications. By utilizing the open pore structure of GOMC, which is also known as CMK-3, a 2.5 V supercapacitor with a high areal capacitance (C_areal ∼ 560 μF cm⁻² at 120 Hz) and a fast frequency response (ϕ ∼ −80° at 120 Hz) was realized. Importantly, the addition of a small amount of CNTs to the CMK-3 results in the formation of an efficient electrical network between the individual CMK-3 particles. The successful conversion of a 60 Hz AC signal to a DC output was demonstrated using the supercapacitors. The advantages of the CMK-3/CNT supercapacitor over a commercial AEC can be extended to applications up to ∼40 V.