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Publication

Identifying Degradation Mechanisms In Lithium-ion Batteries with Coating Defects at the Cathode

Publication Type
Journal
Journal Name
Applied Energy
Publication Date
Page Numbers
446 to 455
Volume
231

Understanding the effect of electrode manufacturing defects on lithium-ion battery (LIB) performance is vital to the quality control process and key to reduce the scrap rate during cell manufacturing. In this regard, it is necessary to quantify the impact of various defects that are generated during the electrode coating process. To this end, we have tested large 0.5 Ah LiNi0.5Mn0.3Co0.2O2/graphite pouch cells with defects intentionally introduced into the cathode coating. Different types of coating defects were tested including agglomerates, pinholes, and non-uniform coating. Electrodes with larger coated/non-coated interfaces had greater capacity fade than baseline electrodes at high current densities, while pinholes and agglomerates did not affect the performance adversely. Visual examination of the harvested electrodes after cycling showed that the anode facing the defective region in the cathode was clearly impacted by the defect. Post cycle analysis of electrodes using Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction provides evidence for a proposed mechanism for material degradation related to the most detrimental type of coating defect.