Electrochemical characterization of lithium cobalt oxide within aqueous flow suspensions as an indicator of rate capability in lithium-ion battery electrodes

Rate capability is a critical metric for assessing lithium-ion battery materials, especially in the electric vehicle industry which requires high battery power density. The typical method for rate capability evaluation of battery materials involves electrode processing, battery assembly, and testing on a battery cycler with varying current rates. This method is very important in evaluating battery materials, however, it is time-consuming and depending on the cell type can take days to weeks. Rate capability can also be affected by other factors besides the active material properties including electrode slurry homogeneity, contact junctions formed during battery assembly, and the connectivity of the interfaces within the battery electrodes. Herein, we will describe the use of a technique termed dispersed particle resistance (DPR) to evaluate the battery cathode active material LiCoO2 (LCO), the first layered oxide evaluated using this method. This new technique works relatively fast, providing qualitative analysis within several minutes, and does not require electrode fabrication or additional materials in the system besides a carrier fluid for the electrolyte. While DPR does not explicitly give rate capability of the materials, DPR was successfully demonstrated to provide the relative rate capability for multiple different LCO samples, as supported by the results obtained from conventional rate capability testing using cycling data. Additionally, the physical properties of the material probed by the DPR were investigated by determining the lithium diffusivity in the crystal structure of the different LCO materials with galvanostatic intermittent titration technique. (c) 2018 Elsevier Ltd. All rights reserved.