The Cottrell Experiment and Diffusion Limitation 1/3 – Introduction

Electrochemically the Cottrell Experiment is very easy. It is easy to perform and the electrochemical process is easy to understand. However, the physical observations during the experiment are important for many electrochemical techniques and experiments. The importance of mass transport, especially diffusion, as a limitation for a flowing current and the additional current flowing due to charging of the electrochemical double layer are basic principles and influence almost every electrochemical experiment.

This series of articles aims to provide an introduction to electrochemical experiments. This series in particular deals with the Cottrell experiment and diffusion limitation, and includes an experiment (PDF) you can carry out yourself. 


The experiment and its discussion should teach:

  • What is capacitive current and what is its influence?
  • How does mass transport limit the current during electrochemical experiments?
  • What is the Cottrell equation?
  • How can a Cottrell experiment be used for analysis?

The Cottrell experiment and diffusion limitation

The following articles will give you the introduction to the Cottrell experiment and diffusion limitation, and finally a PDF of the experiment which you can print and perform yourself!

Please note that teachers can request the answers to the question in the instructions, using