Post-mortem Untersuchung einer Lithium-Ionen-Batterie Pouch-Zelle basierend auf LiNi0.5Mn1.5O4/Graphit Elektroden

Abstract

This thesis investigates post-mortem characteristics of graphite anodes and LNMO cathodes in lithium-ion pouch cells through diverse analyses. After 175 cycles, both anode and cathode maintain stable crystal structures. XPS reveals transition metal dissolution, impacting material stability. Aged graphite anodes show increasing SEI layer thickness, notably inhomogeneous, with the middle sheet thicker. Electrochemical performance varies, with middle layer outperforming. Cathodes maintain ~95% capacity. Carbon component analysis of the SEI layer uncovers carbon oxide species, carbonates, and perfluorinated carbon. These findings enhance understanding of aging dynamics and emphasize the importance of SEI layer behaviour for cell longevity.