An ionic protector to proactively mitigate interfacial degradation induced by electrolyte decomposition in lithium-ion batteries

Abstract

Tetrabutylammonium nonafluorobutanesulfonate (TBNF) is introduced as a capacitive protection electrolyte additive to enhance the performance of high-voltage nickel–cobalt–manganese (NCM) batteries. During charging, the voltage of the positive electrode increases, whereas that of the negative electrode decreases, leading to the migration of cations to the negative electrode and anions to the positive electrode. Based on this principle, an ionic additive for NCM batteries is designed to protect electrodes through capacitive behavior. TBNF suppresses both cathodic and anodic electrolytic decomposition through its extended alkyl chain on the cation and the perfluorinated sulfonate anion. This mitigates the formation of a solid–electrolyte interphase and surface film deposition during cycling. This protection mechanism significantly improves cycling performance, especially under high voltage and temperature conditions. Furthermore, the additive preserves the nominal voltage of the cell, which is essential for energy retention and practical applications. This novel approach can address key challenges in battery design, facilitating the development of more reliable and efficient energy storage systems.