Project 2-8

The project focusses on how impurities in liquid electrolytes affect the physico-chemical processes in lithium-ion batteries, with a particular focus on the solid electrolyte interphase (SEI). Impurities can be introduced directly during recycling (primary impurities) and may alter electrolyte stability, interfacial reactions, and overall cell performance – either directly or through decomposition into more harmful secondary species.

By studying both recycled and model systems, the project aims to determine impurity levels at which cells remain functional and to clarify under which conditions degraded materials can still be reused. The findings will contribute to defining tolerance thresholds and providing guidance for the integration of recycled components into new batteries, supporting more reliable and sustainable recycling strategies.

Specific objectives

• Investigating the influence of impurities on cell performance and changes of the SEI
• Applying electrochemical methods (cell cycling, EIS) together with surface analysis (XPS, FIB-SEM)
• Comparing worst-case contamination scenarios with industrially relevant impurity levels
• Identifying thresholds for impurity tolerance and implications for battery reuse

Expected outcome

• Improved understanding of impurity effects on the SEI
• Identification of impurity levels that still allow functional reuse of recycled materials
• Practical guidelines to support sustainable and efficient battery recycling