UNCONVENTIONAL ADDITIVES FOR IMPROVING THE SOLID ELECTROLYTE INTERPHASE IN LI-ION BATTERIES

Abstract

Optimal formation of the solid electrolyte interphase (SEI) on the negative electrode of lithium-ion batteries (LIB) is related to improved performance, leading to increased capacity retention, lifetime, and safety. In this thesis, more unconventional methods of improving SEI formation are explored. By incorporating solid additives into active materials, utilizing a multifunctional binder additive, and using water as a beneficial electrolyte additive, this work aims to beneficially modify SEI formation for better Li-ion cell performance. LiF was found to be a good solid phase electrode additive in Si-Fe alloys that led to improved capacity retention. Synthesized poly-VC was explored as a binder additive to modify SEI formation in Si-Fe alloy electrodes. Water was introduced as an electrolyte solution additive that led to improved cycling in NMC/Si-alloy full cells. The goal of this work was to find alternatives to the expensive conventional additives currently implemented in LIBs.