Estimating lithium-ion battery behavior from half-cell data

Abstract

The electrochemical behavior of lithium-ion battery electrode materials is often studied in the so-called ‘lithium half-cell configuration’, in which the electrode is tested in an electrochemical cell with a lithium metal electrode acting as both counter and reference electrode. However, the performance of lithium-ion batteries is affected by the electrochemical behavior of the two electrodes composing the battery. Therefore, in order to understand the behavior of battery materials under conditions representative of commercial applications, it is necessary to perform electrochemical measurements in the so-called ‘full-cell configuration’, in which a cathode (e.g. lithium iron phosphate or LFP) and an anode (e.g. graphite) are combined in an appropriate capacity ratio. In this work, we provide further understanding of how the behavior of the electrodes in half-cell configuration affects the electrochemical response of the full cell. For that, we characterize two commercially relevant battery materials, LFP and graphite, in lithium half-cells, and also combined in a LFP vs graphite full-cell. Additionally, we employ the electrochemical response of the LFP and graphite electrodes in lithium-half cells to predict the electrochemical response of the LFP vs graphite full-cell, and the results of our calculations are in very good agreement with the experimental measurements.

Keywords

• Lithium ion
• Battery
• Half-cell
• Full-cell