Solid‐State NMR and EPR Characterization of Transition‐Metal Oxides for Electrochemical Energy Storage

Transition-metal oxides are important cathode materials for rechargeable lithium-ion batteries. During the lithiation and de-lithiation processes, even though the long-range structure is largely maintained to ensure the reversibility and long-term cyclability, the short-range structure evolves in conjunction with changes in oxidation states of transition metals and in many cases the oxygen anions. Magnetic resonance techniques, including solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR), are powerful to track these changes and correlate them with battery performance. This chapter introduces essential NMR and EPR techniques and their applications for characterizing transition-metal oxides used for electrochemical energy storage.