DiffCapAnalyzer: A Python Package for Quantitative Analysis of Total Differential Capacity Data

Abstract

In order to study long-term degradation and charge storage mechanisms in batteries, researchers often cycle these electrochemical cells for hundreds or even thousands of charge and discharge cycles. The raw data produced during cycling can be interpreted via a variety of techniques that each highlight specific aspects of how the battery is functioning. Differential capacity (dQ/dV) analysis, one such technique, results in plots of the differential capacity-the charge introduced into the battery during a small change in voltage-vs. the voltage. Electrochemical reactions result in significant charge introduced into the cell across a small voltage window. In the differential capacity plot, this behavior results in a peak for each electrochemical reaction. Therefore, differential capacity plots are particularly useful for highlighting the various electrochemical events occurring within the cell, specific to each cycle (Aihara et al.