Irreversible Behaviors and Kinetics of Lithiated Products in SiOx Anodes with Inserting Li contents in Li Ion Batteries

Abstract

The irreversible behavior of SiOx anodes during cycling has been investigated by controlling the amount of Li inserted during lithiation. This study mainly focuses on evaluating the amount of irreversible capacity by varying the amount of Li inserted into the SiOx (0.1, 0.5, 1, 2, and 4 mol Li per mol of SiOx, the so called "mol rate'') and investigating the lithiated products using X-ray photoelectron spectroscopy (XPS) after various numbers of cycles were performed at a 0.1 mol rate. It is notified that the irreversible capacity of the SiOx anode increases with increasing lithiation mol rates, meaning that the reaction products (Li2O, Li15Si4, and Li-Si-O products) have different reaction kinetics during lithiation. In particular, the XPS investigations showed that the first reaction product is Li2O, the second reaction product is Li-Si alloy (Li15Si4), and the final reaction product is the Li-Si-O products. (C) 2013 The Japan Society of Applied Physics