Supercapacitors with alternating current line-filtering performance

Doudou Zhao,Xiang Zhu,Jiantong Li,Sheng Han,Xiaodong Zhuang,Emmanuel Kymakis,Kaiyue Jiang,Changchun Ke

doi:10.1186/s42833-020-0009-z

Abstract

Alternating current (AC) line filters have been widely used to smooth the leftover AC ripples on direct current voltage. Currently available commercial aluminum electrolytic capacitors (AECs) are primarily used for this application. However, the bulky volume and low capacitance of AECs have become incompatible with the rapidly developed intelligent electronic devices and industry dynamics. Supercapacitors with high specific capacitance and AC line-filtering performance could become the next-generation candidates to replace AECs for smoothing leftover AC ripples. Thus, most conventional supercapacitors behave like a resistor and not a capacitor at 120 Hz mainly because complex pore structures of electrode materials prevent the diffusion of electrolyte ions. Various electrode materials have been reported to reveal supercapacitors with AC line-filtering performance; however, the balance of high specific capacitance and an excellent filtering efficiency is a prodigious challenge. This review summarizes recently reported supercapacitors based on different types of electrode materials with AC filtering performance and attempts to develop the relationship between different influencing factors and features of functional materials.

Highlights

Direct current (DC) and alternating current (AC) voltages are used for the conduction and transmission of electrical energy
Supercapacitors can be categorized into two types, namely electrical double-layer capacitors (EDLCs), where charge storage occurs through physical adsorption of ions, and pseudocapacitors (PCs), where the chemical adsorption of ions is attained through redox active materials, such as many metal oxides [8–11]
In this review, we summarized the research works in the field of supercapacitors with AC filtering performance

Summary

Introduction

Direct current (DC) and alternating current (AC) voltages are used for the conduction and transmission of electrical energy. Among various types of electrochemical energy storage devices, supercapacitors have received particular attention of scientific and industry communities in recent years because of excellent superior power density, rapid charge/discharge rate, and outstandingly long lifecycle [5–7]. Supercapacitors can be categorized into two types, namely electrical double-layer capacitors (EDLCs), where charge storage occurs through physical adsorption of ions, and pseudocapacitors (PCs), where the chemical adsorption of ions is attained through redox active materials, such as many metal oxides [8–11]. Because of a complex microporous structure in a carbon-based electrode, the EDLC-type supercapacitors conventionally exhibit large electrochemical resistance and can be rarely charged and discharged at a frequency higher than 1 Hz [12, 13]. For PCs, because of inherently low charge transfer on the electrolyte/electrode surface of the electrode material [15], capacitors behave like resistors and not capacitors in 120 Hz, which impedes their applications in AC line filtering [4, 16–18]

Objectives

Findings

Conclusion