Characterization of Surface Free Energy of Composite Electrodes for Lithium-Ion Batteries

One critical step in lithium-ion battery manufacturing process is the electrolyte wetting step, which usually takes up to several days at elevated temperatures, posing a distinctive bottleneck in the manufacturing process especially for large-size cells. The electrode wettability depends on both the surface tension of electrolyte and the surface free energy of electrodes. This work reports a systematic study on the characterization of surface free energy of battery electrodes and the correlation between surface free energy and electrode processing. It shows that, when switching manufacturing from conventional solvent based processing to aqueous processing, the polar component of surface free energy increases 74.1% for NMC532 electrodes and 48.2% for Al2 graphite electrodes. The results provide valuable guidance for electrode processing to optimize the electrolyte wetting process, helping lower processing costs and enable higher product quality and throughput. (C) 2018 The Electrochemical Society.