On the moisture tolerance of LiFSI based lithium-ion batteries: A systematic study on NMC622/graphite full cells
Year: 2024
Type: article
Abstract: Lithium-ion battery (LIB) technology is state-of-the-art energy storage technology for portable electronics and electric vehicles (EVs). In this incumbent LIB technology, lithium hexafluorophosphate (LiPF 6 ) is the most widely used electrolyte salt to date. However, the challenges related to its chemical/thermal stability, sensitivity to moisture and the consequent formation of strong acids such as hydrogen fluoride (HF) need to be resolved with alternative salts. Due to its better chemical/thermal stability, resistance to moisture and HF formation, and better ionic conductivity, lithium bis(fluorosulfonyl)imide (LiFSI) has been considered as a promising alternative electrolyte salt to LiPF 6 . In this study, the effect of addition of 1000 ppm water on LiFSI based electrolytes was systematically investigated by testing NMC622/lithium and artificial graphite/lithium half and NMC622/graphite full cells in four LiFSI based electrolytes; plain LiFSI, LiFSI + 1000 ppm H 2 O, LiFSI + 10 wt% FEC, and LiFSI + 1000 ppm H 2 O + 10 wt% FEC. Post mortem characterization of selected electrodes was also conducted with SEM imaging and XPS to study the surface chemistry and morphology of cycled electrodes. Overall, this study shows that 1000 ppm water can slightly improve the electrochemical performance of NMC622/lithium half cells; however, the same amount of moisture severly degrades the graphite half and NMC622/graphite full cells.
Source: Electrochimica Acta
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,870
Funder: Norges Forskningsråd
OpenAlex ID: W4403266217