In Situ Magic-Angle Spinning 7Li NMR Analysis of a Full Electrochemical Lithium-Ion Battery Using a Jelly Roll Cell Design

A new in situ magic angle spinning (MAS) ⁷Li nuclear magnetic resonance (NMR) strategy allowing for the observation of a full lithium-ion cell is introduced. Increased spectral resolution is achieved through a novel jelly roll cell design, which allowed these studies to be performed for the first time under MAS conditions (MAS rate 10 kHz). The state of charge, metallic lithium plating and solid-electrolyte interface (SEI) formation was captured for the first charge/discharge cycle of a full electrochemical cell (LiCoO₂/graphite). This strategy can be used to monitor both anode and cathode electrodes concurrently, which is valuable for tracking the lithium distribution in a full cell in real time and may also enable identification of causes of capacity loss that are not readily available from bulk electrochemical analyses, or other post-mortem strategies.