Taffit: An Algorithm for Fitting Tafel Data

Abstract

Tafel analysis is widely used to characterize electrochemical kinetics and assess the properties of electrocatalysts for use in fuel cells, electrolyzers, and other applications. This method is limited in part by the subjective determination of linearity, as the kinetic parameters obtained by the regression may vary significantly depending on the chosen linear region. In an effort to increase measurement quality and decrease subjectivity, an algorithm has been developed in Microsoft® Excel® that generates a Tafel plot from an LSV and determines the exchange current density j 0, charge transfer coefficient α, and Tafel slope of closest fit. Comparisons of kinetic parameters between conventional and algorithmic Tafel analysis are made for the hydrogen evolution reaction (HER, 2H+ + 2e- ⇌ H2) for different electrodes. The algorithmic parameters correlate well with conventional methods and show increased measurement precision. Similar agreement is observed between literature and algorithmic fits of representative Tafel plots. The developed algorithm allows for straightforward, rapid, and user bias limited Tafel analysis and can be used to increase measurement quality.