The Effect of Battery Potential and Charge Rate on the Decomposition Reaction on the Anode Electrode of Lithium Ion Polymer Battery

The formation of the solid electrolyte interface (SEI) layer on the surface of the anode electrode prevents further electrolyte decomposition reaction.  However, certain battery operating parameters initiate electrolyte solvent and salts decomposition reaction with lithium on the surface to the anode electrode. This decomposition reaction results in the formation of an insoluble reaction products that is non-uniform, electronically insulating, and unstable on the surface of the graphite particles. The loss/consumption of recyclable lithium ions at the anode by this passivation layer is one of the causes of major reversible capacity loss in the lithium ion battery. Understanding the potential and the charge rate that initiates the formation of the surface film layer is critical to effectively controlling/limiting these operational parameters in order to extend the calendar life performance of the battery.  This paper seeks to investigate the effect of the state of charge and charge rate on the electrolyte decomposition reaction resulting in the formation of the surface film deposit. An image based quantitative analysis of the thickness of the surface film will be conducted to collaborate the observed changes in the electrochemical properties of the battery.