Evaluating the Effect of Electrolyte Additive Functionalities on NMC622/Si Cell Performance
Document Type
Article
Date of Original Version
7-1-2022
Abstract
Unstable electrode/electrolyte interface is the major cause of degradation for silicon (Si)-based anodes for lithium (Li)-ion batteries. Development of functional electrolyte additives can provide a viable path toward stabilizing the dynamic Si/electrolyte interface, which will benefit the development of high energy density Li-ion batteries. Here, we evaluate polymerizable electrolyte additives with varying functional groups (fluorocarbon, thiophosphate, and fluorophosphazene). The additives are examined using LiNi0.6Mn0.2Co0.2O2/Si full cells where the cycle performance and impedance are measured. Electrochemical tests show that the fluorine-containing additives provide better passivation at the Si electrode, leading to enhanced full cell performance. Among the three additives examined, best electrochemical performance is observed from the fluorocarbon-containing compound, followed by fluorophosphazene- and thiophosphate-containing compounds. Characterization of the solid electrolyte interphase (SEI) on cycled electrodes using Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) reveal that higher concentration of fluorine and lithium oxide, and lower concentration of carbonate and organic species correlate with enhanced electrochemical performance.
Publication Title, e.g., Journal
Journal of the Electrochemical Society
Volume
169
Issue
7
Citation/Publisher Attribution
Ha, Yeyoung, Trevor R. Martin, Sarah Frisco, Leah Rynearson, Maxwell C. Schulze, Sang Don Han, Stephen E. Trask, Brett L. Lucht, Glenn Teeter, and Nathan R. Neale. "Evaluating the Effect of Electrolyte Additive Functionalities on NMC622/Si Cell Performance." Journal of the Electrochemical Society 169, 7 (2022). doi: 10.1149/1945-7111/ac7e75.