Magnetic resonance imaging techniques for lithium-ion batteries: Principles and applications

Operando monitoring of internal and local electrochemical processes within lithium-ion batteries (LIBs) is crucial, necessitating a range of non-invasive, real-time imaging characterization techniques including nuclear magnetic resonance (NMR) techniques. This review provides a comprehensive overview of the recent applications and advancements of non-invasive magnetic resonance imaging (MRI) techniques in LIBs. It initially introduces the principles and hardware of MRI, followed by a detailed summary and comparison of MRI techniques used for characterizing liquid/solid electrolytes, electrodes and commercial batteries. This encompasses the determination of electrolytes' transport properties, acquisition of ion distribution profile, and diagnosis of battery defects. By focusing on experimental parameters and optimization strategies, our goal is to explore MRI methods suitable to a variety of research subjects, aiming to enhance imaging quality across diverse scenarios and offer critical physical/chemical insights into the ongoing operation processes of LIBs.