Carbon Based Electrochemical Double Layer Capacitors of Low Internal Resistance

Yurii Maletin,Oleg Gozhenko,Sergey Zelinsky,Denis Gromadsky,Alexander B Rozhenko,Dmitry Drobny,Volodymyr Strelko,Natalia Stryzhakova,Vitaliy Volkov,Sergey Tychina

doi:10.5539/eer.v3n2p156

Abstract

Based on nanoporous carbon electrodes electrochemical double layer capacitors (EDLC), otherwise known as supercapacitors or ultracapacitors, are currently widely used in various energy storage technologies, wherein the EDLC low internal resistance and long cycle life are at an advantage. It is still a good challenge to further reduce the internal resistance of EDLC since this can result in higher power density and higher efficiency of these promising power supply units. In this work it has been found that the EDLC internal resistance depends strongly on the electrolyte diffusion in the carbon electrode nanopores, and two techniques to measure the in-pore diffusion coefficients, namely, those based on spin-echo NMR or cyclic voltammetry with the use of porous rotating disc electrode are described. Cyclic voltammetry, impedance spectroscopy and transmission electron microscopy have also been used to select the best EDLC components. As a result, EDLC devices of very low internal resistance and high power density have been developed.

Highlights

1.1 Why It Is of InterestThere is an obvious increasing interest in electrochemical double layer capacitor (EDLC) technology and application all over the world, in particular, in renewable energy and hybrid vehicle applications
In this work it has been found that the electrochemical double layer capacitors (EDLC) internal resistance depends strongly on the electrolyte diffusion in the carbon electrode nanopores, and two techniques to measure the in-pore diffusion coefficients, namely, those based on spin-echo NMR or cyclic voltammetry with the use of porous rotating disc electrode are described
Low internal resistance predetermines the effectiveness of EDLC application in combined power supply units, wherein an EDLC device is connected with a battery either in parallel or in series

Summary

Introduction

1.1 Why It Is of InterestThere is an obvious increasing interest in electrochemical double layer capacitor (EDLC) technology and application all over the world, in particular, in renewable energy and hybrid vehicle applications. EDLC devices can provide the key to a number of efficient power solutions that are mainly related with various backup systems to compensate short-term voltage surges or drops or with load leveling the batteries in various combined power sources. Low internal resistance can be one of key advantages of EDLC over all other types of energy storage devices since the round trip efficiency and power capability of the devices are inversely proportional to their internal resistance. This, accompanied by EDLC long life cycle and wide operation temperature range, can help them to clear their way to the market. EDLC devices must clearly demonstrate much higher power capability than Li-ion or any other type of batteries, but this is not always the case.

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Conclusion