jats:titleAbstract</jats:title>jats:pDue to their diversity in the composition, lattice structures and physical/chemical properties, and various oxidation states (2+, 3+, 4+, and 5+), (Vjats:italicjats:subx</jats:sub></jats:italic>Ojats:italicjats:suby</jats:sub></jats:italic>) nanomaterials have attached much attention for developing new rechargeable batteries, including lithium‐ion batteries (LIBs), sodium‐ion batteries (NIBs), zinc‐ion batteries (ZIBs), and magnesium‐ion batteries (MIBs) as well as new energy storage concepts such as light‐rechargeable batteries. However, to further improve the electrochemical performance of Vjats:italicjats:subx</jats:sub></jats:italic>Ojats:italicjats:suby</jats:sub></jats:italic>‐based batteries, it is crucial to understand the various electrochemical mechanisms taking place in these materials for LIBs, NIBs, ZIBs, and MIBs. This review covers a systematical discussion of in situ and operando analysis methods carried out on Vjats:sub2</jats:sub>Ojats:sub5</jats:sub>, VOjats:sub2</jats:sub>, Lijats:italicjats:subx</jats:sub></jats:italic>Vjats:italicjats:suby</jats:sub></jats:italic>Ojats:italicjats:subz</jats:sub></jats:italic>, Najats:italicjats:subx</jats:sub></jats:italic>Vjats:italicjats:suby</jats:sub></jats:italic>Ojats:italicjats:subz</jats:sub></jats:italic>, Znjats:italicjats:subx</jats:sub></jats:italic>Vjats:italicjats:suby</jats:sub></jats:italic>Ojats:italicjats:subz</jats:sub></jats:italic>, and Mgjats:italicjats:subx</jats:sub></jats:italic>Vjats:italicjats:suby</jats:sub></jats:italic>Ojats:italicjats:subz</jats:sub></jats:italic> for LIBs, NIBs, ZIBs, and MIBs and the fundamental insights they have provided in the energy storage mechanisms in these batteries.</jats:p>