Essential Potentiostats

VSP Potentiostat.

5 channels - A versatile, research grade, multichannel electrochemical workstation

EIS measurement from 10 µHz to 1 MHz, Current ranging from 10 μA up to 1 A

Built around a 5-channel modular chassis the VSP is a versatile, research-grade potentiostat.

This highly modular electrochemical-workstation can reply to the needs of all scientists with options for EIS capability, low current, high-current booster and additional potentiostat channels.

The internal 4 A option takes two slots in the VSP chassis and requires a potentiostat board. External boosters from 2 A up to 100 A can be used with each channel in the VSP.

General

General
Slots availableUp to 5
Electrodes connections2, 3, 4, 5
Compliance20 V adjustable from ± 10 V between [-20 ; 20] V
Acquisition time 20 µs with EC-Lab Express, 200 µs with EC-Lab.
Live processed data : 200 µs, independent of sampling rate (Q charge, Q discharge, Energy, Power...)
SoftwareEC-Lab, EC-Lab Express, EC-Lab developper package
Add-ons compatibilityYes
Dimension (W x D x H)435 x 335 x 95 mm
Weight8 kg
Power requirement300 W
InterfacesEthernet (Direct, LAN, Wifi), USB 2.0

Channel specifications

Control
Measurement
Voltage
RangesCustomizable ranges. Compliance of 20 V adjustable (example 0 - 20 V). Up to 60 V with FlexP-0060± 2,5 V, ± 5 V, ± 10 V. ± 10 V adjustable (example 0 - 20 V). Up to 60 V with FlexP0060/FlexP0160
Accuracy< 0.1 % FSR* (20 mV)< 0.1 % FSR* (20 mV)
Resolution5 µV to 305 µV76 µV below 10 V, 152 µV from 10 to 15 V, 305 µV from 15 to 20 V
Current
Ranges
± 10 µA to ± 1 A (6 ranges). Automatic current range available. Up to 800 A with four FlexP-0012.
Accuracy
< 0.1 % FSR* (min 20 nA)
Resolution
0.004 % of the range (min 760 pA)
EIS
EIS capability
1 MHz to 10 µHz
EIS quality indicators
Yes (with "e" type channel board)

*FSR = Full Scale Range

Advanced

Advanced
Floating optionsCE to ground
Permeation (WE to ground)No
Multi-electrode (CE to ground)Yes (with "e" type channel board)
FiltersSoftware
Input/ouput2x analog inputs
1x analog output
3x TTL (trigger input/output, and safety)
2x monitor outputs (current and voltage)
Stability control mode 7 bandwidths
CalibrationMore than 50 verified points.

What should I do if I have an issue?

In case of problems, information on your hardware and software configuration is necessary to analyze and finally solve the problem you encounter.

 

If you have any questions or if any problem occurs that is not mentioned in this document, please contact your local retailer. The highly-qualified staff will be glad to help you.

Please keep information on the following at hand:

  • Description of the error (the error message, mpr file, picture of setting or any other useful information) and of the context in which the error occurred. Try to remember all steps you had performed immediately before the error occurred. The more information on the actual situation you can provide, the easier it is to track the problem.
  • The serial number of the device located on the rear panel device.
  • The software and hardware version you are currently using. On the Help menu, click About. The displayed dialog box shows the version numbers.
  • The operating system on the connected computer.
  • The connection mode (Ethernet, LAN, USB) between computer and instrument.

Should I use Ethernet or USB?

While most BioLogic electrochemical workstations provide a choice of either USB or Ethernet communications, Ethernet is by far more reliable and at least an order of magnitude faster in data transfer speeds.

While USB is typically “plug and play” for connecting, the USB communications tend to be less reliable and “time out” on some PCs that may not be equipped with good USB chipsets designed for the continuous communications required by an electrochemical system. For those that experience USB time out issues, the use of an aftermarket USB hub (connected between computer and BioLogic device) has proven to increase the reliability of USB communications in most cases.

However, Ethernet is still the preferred communication, especially if it is a multi-channel system in use. For Ethernet connections, refer to the Installation and Configuration manual supplied with your BioLogic system, or the PDF version located in the Help menu of the software.

How can I validate that my potentiostat is working properly?

Thanks to the BioLogic instruments modularity, the user may add afterwards the channel(s) by themselves. The board installation can be validated in two steps:

  • Firstly, it is recommend to calibrate the channel with the calibration tool which is available in the “Tools” menu of EC-Lab®. The procedure is described at the end of the “Installation & configuration manual” and also in the Technical Note #18.
  • If a further check is needed, it is possible to validate the boards thanks to the dummy cells provided with the board(s).

How do I connect with Ethernet?

Connecting and communicating with Ethernet involves setting the computer’s Ethernet circuit to the proper static IP address to connect to the BioLogic instrument.  The instructions to do that are provided below and they assume that the instrument is set to the factory default IP Address of 192.109.209.128.  Once Ethernet communication is established, then the IP Address of the instrument may then be changed to then operate on a LAN if that is so desired.

  1. Select “PC Settings”
  2. Select “Control Panel”
  1. Set “View by:” to Small icons, and then select “Network and Sharing Center”
  2. Select “Change Adapter Settings”
  3. Select “Ethernet”
  4. Select “Properties”
  5. Scroll down and double-click “Internet Protocol Version 4”
  6. Set it to “Use the following IP address:” and set the IP address and Subnet mask as shown above. Once changed, select “OK” and exit back to Windows Desktop to launch EC-Lab and try to connect to the potentiostat via Ethernet connection.

What temperature control chambers can EC-Lab control?

EC-Lab can control through EXT APP technique the F4 & F4T ccontroller from Watlow. So to make sure that the climatic chamber can be controlled by EC-Lab®, check which controller is used.

How should I connect my cell cable leads to my cell?

According to the cell design, BioLogic electrochemical workstations allow the user to customize its setup to stress the cell and get the information of interest.

To understand how the connections affect the measurements, it is important to know how the instrument is working. This is described in the Application Note #4. Basically, in standard configuration, in potentiostatic mode, the instrument applies a voltage between the Working and the reference electrode and measures a current between the working and the counter electrode. In galvanostatic mode, the instrument applies a current between the working and the counter electrode and measures a voltage between the Working and the reference electrode.

 

The most typical connection modes are the 2-electrode, 3 electrode setup, kelvin probe connection and multielectrode…

There are some differences between the Essential and the Premium product ranges so please refer to the instrument’s manual and the videos available for more detailed information.

What are the temperature ranges of the cell cables?

The cell cables can be used between -20°c and 70°C. outside this range the lifetime of the cell cable will be impacted.

How do I know if my reference electrode is working properly?

There are two critical parameters that characterize a reference electrode: the voltage and its impedance. The voltage should be stable over time, it has to be checked periodically by perfomring an OCv measurment in two electrode setup using a “golden” reference electrode. The impedance of the reference electrode has to be below 1 kOhm. This values can be checked by running an EIS measurement in two electrode setup using a “golden” reference electrode.

What causes a “control amplifier overload?”

Any time there is a question or doubt regarding the proper operation of a potentiostat channel, one should utilize the dummy cell that ships with every electrochemical workstation and perform validation experiments as outlined in Bio-Logic Tech Note #36.  One such situation is when a “control amplifier overload” message occurs when running an experiment.  If the dummy cell tests result in a “control amplifier overloads,” this is a good indication that a hardware issue such as a malfunctioning cell cable (due to broken leads, contaminated connectors, or electronic component failure) or failed components on the potentiostat channel itself.  A Tools > Channel Calibration will be needed to help determine the possible component failures.

 

However, if the dummy cell experiment proceeds without a control amplifier overload, then it’s most likely an issue at the cell.  There are many things that can cause a control amplifier overload, but the most common reasons include:

 

If the message occurs at the beginning of the experiment…

 

  1. Leads not connected properly to the cell.
  2. Bent shields and/or pins on the potentiostat cell cable interface.  Inspect the potentiostat and cell cable interface connectors for anything that might appear bent or out of place.
  3. Wrong cable connected to cell when using a multi-channel (happens when a cable labelled “Channel 4” is connected to the cell and user has selected Ch4 in the software, but cable is actually connected to a different potentiostat channel than labelled on the cable).
  4. The cell is grounded (often from another instrument or probe being connected to it in addition to the potentiostat leads).
  5. Cell design with too much impedance between RE and CE, such that the total voltage between WE and RE and RE and CE exceeds the compliance voltage of the potentiostat at any applied voltage.
  6. Bubbles formed in the cell around the tip of reference electrode, breaking electrical continuity between the reference electrode and sample under test.
  7. Reference electrode frit/membrane became clogged resulting in instability of potential control > oscillation > power amplifier overload.
  8. Cell much more capacitive than resistive in nature, which makes it difficult for the potentiostat to maintain a DC voltage, which in turn could lead to an oscillation in the power amplifier.  In this case, setting the Bandwidth to a lower value (6 or 4, for example) could help that scenario.

 

If the message occurs during the experiment…

 

  1. Again, cell design with too much impedance between RE and CE, such that the total voltage between WE and RE and RE and CE exceeds the compliance voltage of the potentiostat at some point during a voltage scan. An “H-cell” is a good example.
  2. Bubbles formed in the cell and broke electrical continuity between the reference electrode and sample under test.
  3. Reference electrode frit/membrane became clogged during test, resulting in instability of potential control > oscillation > power amplifier overload.
  4. Cell changed during the experiment becoming far more capacitive than resistive in nature, which makes it difficult for the potentiostat to maintain a DC voltage, which in turn could lead to an oscillation in the power amplifier.  In this case, setting the Bandwidth to a lower value (6 or 4, for example) could help that scenario.
  5. Cell cable lead came loose from the cell during an experiment (which would break the circuit of current flow), caused by vibrations or other movements of the cell cables during experiment.

 

What is the Bandwidth variable in my technique settings?

To state it simply, the bandwidth is dealing with how fast the instrument is able to react. This is the regulation loop of the instrument, specifically the regulation loop of the control amplifier (CA). More info in AN4 and TN 35.

Which GCPL technique should I use?

To meet the need of most of the battery test protocols, several GCPL (GCPL means Galvanostatic Cycling with Potential Limitation) techniques are available in EC-Lab®. Each technique was designed to perform specific measurements.

Why does my data appear noisy?

“Noisy data” (aka, fluctuations in the current and/or voltage data) is most often due to the cell and/or its surroundings.  Determining the source of the noise is best done with the use of a “dummy cell” consisting of resistors and capacitors.  With every system we sell, we ship along with it a dummy cell that is an excellent tool to help trouble-shoot a system.  BioLogic Tech Note #36 describes using this dummy cell.  If the noise is in the nA or lower range, then you might need to secure a larger resistor in the Mohm range to test out the system.  If you connect the potentiostat/galvanostat up to the appropriate dummy cell and the noise goes away (or is at least “normal”), then the source of the noise is most likely cell related.  If the noise is still present, then it could be environmental related, or an issue with the electrochemical system.  Here are some possible sources of noise in electrochemical measurements:

 

  1. A grounded cell can cause noise issues.  A “very grounded” cell would cause a power amplifier overload, but a somewhat or slightly grounded cell (a few oms of resistance between the cell and ground) would cause noise in the data.  A cell that is grounded should ideally be ran with a system that has “floating” capability like our SP-200/300 systems. In some cases, one might be able to use BioLogic’s “CE to ground” mode (a selection in the Advanced Settings tab, as well as different lead connections to the electrodes), but this depends on the severity of the ground.
  2. A bad reference electrode or bridge tube (aka, luggin), one with too high of impedance across its frit can cause noisy data.  This can typically be determined by replace the standard RE with a Pt wire.  While the data might not be valid with the Pt wire as the RE, if the noise is gone, then the RE is the likely culprit.
  3. A flow cell can be a tricky cell to work with, and proper design and good flow are critical.  Flow cells where the RE is upstream from the WE is an example, as these rarely work well.
  4. A capacitive sample/working electrode can result in noisy data.  You can reduce the noise some by selecting a Bandwidth that is slower (lower number in our parameter settings), but you can never get rid of all the noise.  Only a true analog potentiostat can scan a capacitor with low noise (like our analog ramp generator option for our SP-200/300 systems).
  5. Operating at the limits of resolution and/or accuracy can appear as noise in the system, so make sure the magnitudes and pk-pk values are within the specifications of the system in use.
  6. Environmental sources of noise include:
    1. Magnetic stirrers
    2. Mechanical stirring that is turbulent
    3. Cell cables laying near any other current-carrying leads, power cords being the most often issue (laying the cell cable near or across a power cord or power strip).  While our cables and leads are shield, that does not make them 100% resistant to the effects of strong electrical fields.
    4. Any other electrical devices near the cell that could be putting out significant EMFs

 

It is highly recommended to use a Faraday cage if environmental noise is the source, such as our FC-45 Faraday Cage.

What is the difference between accuracy and resolution?

More information about the difference between accuracy and resolution can be found inside the following topic:

TOPIC: Resolution, Precision, Accuracy, Temperature stability and Time base:  the five to watch 

How can I export my data?

There are different methods to export the data. The export can be done on-line (see EC-Lab user’s manual), off-line and from the graph using the copy data (EC-Lab Analysis & Process data manual).

Why is my coulombic efficiency > 100 % ?

The coulombic efficieny (CE) is the ratio of the input charge and the ouput charge. If the charge is not completed (the first cycle for example), the value of the CE will be overestimated and lead to a value higher than 100%. So make sure that the charge and the discharge are perfomred in the exact same conditions (same starting and same final voltage cutoff limits).

Accessories

You may want to complete your set-up with.

The following accessories are relevant to the VSP potentiostat

Increased Scope. Greater flexibility. Other products

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