4-terminal Kelvin type connector battery holders for eis

4 Terminal Measurements for EIS of Batteries-Coin Cell & Cylindrical

Posted on October 2, 2014May 29, 2018 by Dr.Bob

Purpose of This Note
This application note discusses the differences between 2‑point and 4‑point measurements of batteries. These two typical setups are compared with Gamry’s battery holders for CR2032 coin cells and cylindrical 18650 batteries. Both holders allow direct‑contact Kelvin sensing.

EIS measurements are performed with two types of lithium‑ion batteries and different experimental setups. In addition, shorted lead measurements show the low‑impedance limits of Gamry’s 18650 and CR2032 battery holders.

Introduction
It is crucial to know the exact specifications when testing batteries or any other energy storage device. Many parameters affect the capability of a battery, e.g. electrolyte, electrode materials, and temperature.

Batteries have to pass different tests to check their capacity, voltage window, current rating, internal impedance, leakage current, cycle life, operational temperature range, as well as several impact tests.

In order to get correct, reliable, and reproducible results, researchers have to rely on their experimental setup. Wrong setups can heavily affect and falsify measurement results leading to inaccurate conclusions.

The following sections show by means of EIS experiments the influence of the setup on the actual result. Common battery setups are compared with Gamry’s direct‑contact 4‑terminal battery holders. Shorted lead measurements with dummy cells show the lower limits of Gamry’s battery holders.

Dual Cell CR2032 and 18650 Battery Holder
Figure 1 shows typical options to connect cylindrical batteries and coin cells. Some batteries can be purchased with soldered tabs on each electrode. They allow connecting alligator clips for measurements. If no tabs are available, simple battery holders with two contacts are often used.

Figure 1 – Selection of battery connectors for cylindrical batteries and coin cells.

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Gamry eQCM 10M Quartz Crystal Microbalance

Combined EQCM and Probe Beam Deflection in Deep Eutectic Solvents

Posted on September 22, 2014May 29, 2018 by Dr.Bob

Gamry Instruments is pleased to announce the publication of a manuscript highlighting the capabilities of the Gamry eQCM 10M. The project entitled “Application of the combined electrochemical quartz crystal microbalance and probe beam deflection technique in deep eutectic solvents” uses the EQCM/PBD method for the first time applying to metal deposition/dissolution processes in deep eutectic Read more about Combined EQCM and Probe Beam Deflection in Deep Eutectic Solvents[…]

Gamry Instruments to Exhibit at Eurocorr 2014

Posted on August 29, 2014May 29, 2018 by Dr.Bob

Gamry Instruments will be an exhibitor at The European Corrosion Congress in Pisa, Italy Gamry Instruments is proud to be an exhibitor at EUROCORR 2014, the annual event of the European Federation of Corrosion Philadelphia, PA Gamry Instruments, designer and manufacturer of electrochemical instruments, will be an exhibitor at EUROCORR 2014– September 8-12, 2014 in Read more about Gamry Instruments to Exhibit at Eurocorr 2014[…]

65th Annual ISE Meeting August 31 – September 5, 2014 Lausanne, Switzerland

Gamry Instruments to Attend 65th Annual ISE Meeting

Posted on August 26, 2014April 7, 2015 by Dr.Bob

Gamry Instruments will be an exhibitor at The International Society of Electrochemistry Meeting in Lausanne, Switzerland Gamry Instruments is proud to be an exhibitor at the 65th Annual Meeting of the International Society of Electrochemistry entitled Ubiquitous Electrochemistry Philadelphia, PA, Aug. 20, 2014 Gamry Instruments, designer and manufacturer of electrochemical instruments, will be an exhibitor Read more about Gamry Instruments to Attend 65th Annual ISE Meeting[…]

The 65th Annual ISE Meeting August 31 - September 5, 2014 Lausanne, Switzerland

International Society of Electrochemistry Annual Meeting

Posted on August 26, 2014May 29, 2018 by Dr.Bob

The 65th Annual ISE Meeting August 31 – September 5, 2014 Lausanne, Switzerland The meeting will be held in the Swiss Tech Convention Center (STCC) on the campus of the Ecole Polytechnique Fédérale de Lausanne (EPFL), which includes other architectural landmarks such as the Rolex Learning Center. Electrochemistry involves chemical phenomena associated with charge separation Read more about International Society of Electrochemistry Annual Meeting[…]

Handheld Electrochemical Sensor

Posted on August 26, 2014April 7, 2015 by Dr.Bob

Detects Diseases, Measures Biomarkers, Costs $25 In advanced industrialized nations most diagnostic tests that check body fluids for markers of disease make use of specialized sensors and devices that, although they deliver accurate results, can be very expensive. Now researchers at Harvard University have unveiled a new portable device that can perform a slew of Read more about Handheld Electrochemical Sensor[…]

Characterization of an Electroactive Polymer Film

Posted on August 26, 2014May 29, 2018 by Dr.Bob

EQCM Investigations

This Application Note is intended to provide the reader with a general framework for characterization of an electroactive polymer film. Electropolymerization is a convenient way to control film growth either through repeated cycling, potential steps, or current steps. Examination of the film redox behavior in monomer-free, fresh electrolyte provides insight on doping and dedoping of these polymer films.

Polybithiophene films were assembled by cycling an Au-coated 10 MHz quartz crystal between 0 and 1.5 V in the presence of 1 mM bithiophene solution containing 100 mM tetrabutylammonium perchlorate (TBAP) in acetonitrile (MeCN). Potentials are reported against a Ag/Ag+ pseudo-reference electrode. The Teflon® cell was outfitted with a Teflon o-ring to prevent swelling from the acetonitrile and placed inside a VistaShield™. The cell was connected to an eQCM 10M™ which was coupled to a Reference 600™. Both instruments were connected to a computer running Resonator™ version 5.67. Bithiophene, electropolymerizes via a two-electron oxidation at potentials greater than ~1.25 V versus a Ag/Ag+ pseudo reference electrode.

Figure 1 shows two cycles of film growth. Cycle 1 (blue curve) shows only background (non-Faradaic) current until the potential is greater than 1.25 V. Cycle 2 shows additional Faradaic current beginning at approximately 0.75 V due to oxidation of the polymer film. Polymerization still happens at potentials greater than 1.25 V. The small spike at 1.1 V is related to an irreversible film rearrangement since subsequent cycles (seen when thicker films were prepared) show no current spike.

Figure 1: Electropolymerization of 1 mM bithiophene in 0.1 M TBAP/MeCN. Scan rate was 50 mV/s.

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The Battery Show Conference & Expo for Advanced Batteries

Posted on August 14, 2014June 26, 2015 by Dr.Bob

The Battery Show’ is being held September 16-18 2014 in Novi, Detroit Michigan. This will be the premier showcase of all the latest advanced battery technology and is an ideal venue for tech leaders, scientists, engineers, project leaders, buyers and executives concerned with advanced energy storage. The latest advanced battery solutions for electric & hybrid Read more about The Battery Show Conference & Expo for Advanced Batteries[…]

Porous Glass Frit Glass

Posted on August 12, 2014May 29, 2018 by Dr.Bob

Care of Porous Glass Frits

Porous Glass is often used at the end of a reference electrode or a bridge tube to allow electrical, ionic conductivity between the bulk of the solution and the internal filling solution, while preventing large scale convective mixing of the solutions. Porous Glass, or “thirsty glass” is a porous glass with a fairly low leak rate.

The Porous Glass frits, however, are not immortal!

To preserve their useful lifetime, they should be kept wet. If they are allowed to dry out, solid crystals can clog the narrow pores and increase the electrical resistance. In extreme cases, the Porous Glass can crack upon drying out.

When not in use, the reference electrode or bridge tube can be stored with the Porous Glass frit immersed in distilled water. Diffusion through the Porous Glass is fairly slow, and the internal filling solution will not be diluted, even upon a few weeks of storage.

An alternative is to replace the small plastic cap that was in place when the reference electrode was shipped.

Replacing a Porous Glass Frit

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orous Electrodes and the Nomenclature That Will Be Used in This Paper.

Transmission Lines

Posted on August 8, 2014May 29, 2018 by Dr.Bob

What Are They?

Why Are They Useful?

Introduction

Porous electrodes offer a high surface area to volume or weight ratio which is highly beneficial to a number of energy generation or storage devices. (e.g. Dye-Sensitized Solar Cells, Super-Capacitors, Fuel Cells, etc). Transmission lines are heavily used in modeling in Electrochemical Impedance Spectroscopy (EIS) experiments where porous systems are employed.

Though transmission lines are commonly used, an introductory paper was hard to find. This paper is intended to serve that purpose. It assumes basic knowledge of EIS and modeling using equivalent circuits as covered in our EIS application note.

Nomenclature and Notation

We will distinguish between the base electrode and the porous electrode and the various interfaces as shown in Figure 1.

Figure 1. Porous Electrodes and the Nomenclature That Will Be Used in This Paper.

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There is a description of potentiostat stability (written by DK Roe) in the Kissinger & Heineman book (

A Basic Understanding of iR Compensation

Posted on August 8, 2014May 29, 2018 by Dr.Bob

Some of the most common technical questions we hear have to do with iR compensation —

Where does uncompensated iR come from?
Do I need to use iR compensation with my experiment?
How should I set up the iR compensation parameters?
Why doesn’t iR compensation work on my system?

In this post we’ll attempt to answer these questions and to give you a basic understanding of iR compensation.

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ompliance voltage is the voltage available at the counter electrode that can be used to force current to flow and still maintain control of the working electrode voltage.

How to Speak Potentiostat Compliance

Posted on August 8, 2014May 29, 2018 by Dr.Bob

What’s important in the selection of a potentiostat? That depends greatly on its intended use. This page addresses an often misunderstood term.

Compliance voltage

Compliance voltage is the voltage available at the counter electrode that can be used to force current to flow and still maintain control of the working electrode voltage. The compliance should be specified in conjunction with a current value: “20V @ 250mA” or “20V @ full rated current”. An amplifier’s output voltage decreases at higher currents due to the output impedance of the amplifier.

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