Supercapacitors

Gamry’s potentiostats are well suited for battery testing of materials to coin cells and all the way to large format cells.  We even have a system for stack testing.

Additionally, all of our potentisotats are electrically isolated from earth-ground (aka floating) so they are ideal for testing of grounded cells or working in conjunction with large DC power supplies.  

Our software has been optimized for battery testing needs.  We have many techniques available but the main selection of techniques for battery testing are revolve around electrochemical impedance spectroscopy, charging/discharging and pulsing techniques meant to mimic drive cycles, for example.  We also have ancillary techniques such as PITT/GITT.  

Gamry's EIS software also includes a powerful Autofit™ routine that takes the guesswork out of estimating initial parameter values in your battery model. You can view the video EIS of Lithium ion Battery.  This can be very valuable when processing EIS data. Gamry's multisine techniques called OptiEIS and CombiEIS are not your standard multisine technique.  Gamry's multisine technique contains two unique algorithims for improving signal to noise ratio.  

Supercaps provide a challenge to normal potentiostatic testing in that their response to a voltage step produces theoretically infinite current.  This causes most potentiostats to (however briefly) hit the current rail and stay there until the instrument comes into compliance.  Capacitors in general are also problematic for digital instruments when running, e.g. cyclic voltammetry—an excellent tool for supercap researchers. 

Gamry has tools to work through both problems.  PWR800 potentiostatic experiments (other than CV) operate in a special mode that records all current data, ensuring no fraction of the capacity is lost due to potential steps.  In cyclic voltammetry, Gamry’s surface mode preserves capacitance information (as well Faradaic current from bound species), allowing it to accurately measure supercaps.

Recommended Supercapacitor Systems

When testing materials and coin cells, the Interface 1010E is our recommended setup.  For increased capacities or current needs we recommend the Interface 5000P or 5000E or the Reference 3020.   For larger format cells we recommend the Reference 3020 or 3020AE in conjunction with our Reference 30K Booster.  When high-throughput battery test equipment is needed we recommend our multichannel setup.  Any of our potentiostats can be configured into a multichannel setup, giving you the greatest flexibility possible.

Gamry has also partnered with Kolibrik.net* to distributor their potentiostats in several territories through the world. Kolibrik provides instruments potentiostats/galvanostats of various capabilities, each including EIS. They are 5V/20A, 5V/50A, 5V/100A, 10V/20A, and 10V/50A. Kolibrik even has a MegaEIS system that can handle up to 1000V/2000A. Note though that the DC discharge must be larger than the AC amplitude for EIS using the MegaEIS. 

We also have several small accessories available that can be very useful.  For materials testing we have both the Lithium Ion Battery Materials Cell and the Dr. Bob's Electrochemical Cell.  We also have several very useful battery holders that utilize four-probe contacts to give the best impedance result possible.  Four-probe connections are necessary to eliminate the effect of contact resistance when connecting the sense leads to your cells.  Not utilizing four-probe connections can significantly affect your results.  Our battery holders have also been designed to reduce mutual inductance between the current-carrying cables and the sense cables. 

*Gamry distributes Kolibrik potentiostats in North America, China, Italy, Belgium, The Netherlands, Luxembourg, Slovakia, and Czech Republic. Contact your local distributor or Kolibrik directly for other territories.