Repeating Chronopotentiometry

Introduction

Run a Repeating Chronopotentiometry test by selecting Experiment > Physical Electrochemistry > Repeating Chronopotentiometry on the Framework™ menu bar.

Repeating Chronopotentiometry is an extension of Gamry Instruments’ Chronopotentiometry script. It allows you to repeat a Chronopotentiometry test over multiple cycles. The number of cycles must be a positive integer.

This is a multipurpose test. Many uses involve modification of an electrode surface. If the applied currents are sufficient to form and then reduce an oxide layer on the electrode, repeated cycles usually roughen the electrode. Repeated plating and partial de-plating steps can create high-quality plated surfaces.

Setup Parameters

The setup window for Repeating Chronopotentiometry is identical to the setup for Chronopotentiometry, except for the addition of a Cycles parameter.

Each cycle generates m data points, where:

m = Step 1 Time / Sample Period + Step 2 Time / Sample Period

The total number of points in the data curve is Total Points:

Total Points = Cycles × m

Immediately after Setup, the number of points required for the test is compared to the maximum points allowed in a Chronopotentiometry curve. If you asked for more than the allowed number of points, an error window appears. Resolve the problem by:

When the test is run, all pre-step actions (Conditioning, Initial Delay, etc.) are performed once. The script then:

  1. Applies the Step 1 Voltage for the Step 1 time,
  2. Applies the Step 2 Voltage for the Step 2 time,
  3. Increments a completed Cycles counter,
  4. Stops the test if the completed Cycles counter exceeds the Cycles parameter
  5. Loops back to Step 1 if more Cycles are needed

Results

The result of the test is a curve containing current- and voltage-versus-time data points. All the steps are contained within one data curve.

You can open the data file in Gamry Instruments' Echem Analyst™ program.