Ag@Activated Carbon Felt Composite as Electrode for Supercapacitors and a Study of Three Different Aqueous Electrolytes

Aline Castilho Rodrigues,Jorge Tadao Matsushima,Jossano Saldanha Marcuzzo,Andrés Cuña,Mauricio Ribeiro Baldan,Elen Leal Da Silva,Emerson Sarmento Gonçalves,Sandro Fonseca Quirino

doi:10.1590/1980-5373-mr-2018-0530

Abstract

The main challenge for the development of a high efficiency supercapacitor is the electrode material. Developing electrode materials with high specific electrical capacitance and low electrical resistance enables an increase in the energy accumulated in the device. In addition, it is expected that the electrode material presents a simple procedure for preparation having low production cost and being environmentally friendly. This work is based on the deposition of silver nanoparticles on activated carbon felt (Ag@ACF) as a supercapacitor electrode. The samples were characterized by field emission gun scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and textural analysis. Supercapacitor behavior was evaluated by galvanostatic charge-discharge curves, cyclic voltammetry and electrochemical impedance spectroscopy using a symmetrical two-electrode Swagelok type cell, and three different aqueous solution electrolytes: 2 M H2SO4, 6 M KOH and 1 M Na2SO4. Ag@ACF presented a high specific capacitance in KOH, about 170 F g-1, which makes it an interesting material for supercapacitor electrodes and it showed good specific electrical capacitance, low resistance and high cyclability.

Highlights

Nowadays, there is a great interest in renewable and clean energy sources due to energy demand related to the technological development as well as the preoccupation with the exhaustion of the natural resources
The surface micrographs of activated carbon felt (ACF) and Ag@ACF are illustrated in Figure 1a and 1b, respectively
It is observed that in specific regions there is a formation of silver clusters on ACF surface

Summary

Introduction

There is a great interest in renewable and clean energy sources due to energy demand related to the technological development as well as the preoccupation with the exhaustion of the natural resources. Based on these considerations, the development of electrochemical supercapacitors (ES), is the focus of the technological research areas for energy demand regarding energy storage and conversion. Since the WS of ESs depends on the capacitance (C) and square of the cell voltage (V), increasing either or both the C and V becomes an effective way to increase WS. Electrode materials with high capacitance, electrolytes with large working potential windows and integrated systems with a new and optimized structure have been explored.[3,4]

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Conclusion