Probing the Electrode-Electrolyte Interface in Rechargeable Batteries by Solid State NMR

Reactions at the electrode-electrolyte interface in lithium ion batteries play a key role in the battery’s performance and are one of the main causes for cell failure. These reactions, which lead to the formation of the solid electrolyte interphase (SEI), ultimately control the reversibility of the cell’s Li chemistry and its kinetics. Thus an important part in the development of new high energy storage materials is control over their interfacial chemistry and reactivity with the electrolyte. Nuclear magnetic resonance (NMR) spectroscopy is an excellent approach for following the formation of interfacial layers as it can detect disordered and heterogeneous phases, providing information on their chemical composition, structure and dynamic properties. Its main disadvantage is its low sensitivity which is often a limiting factor when probing the SEI. Here I’ll describe approaches to overcome this sensitivity limitation by isotope enrichment as well as the potential of new hyperpolarization techniques which can provide detailed molecular level insight into the chemistry of the SEI.