Advancing next-generation rechargeable batteries requires a precise understanding and control of nanostructural changes during

operation. Small-angle neutron scattering (SANS) has emerged as a powerful, non-destructive characterization technique 

that uniquely complements traditional methods such as TEM and SAXS. With high sensitivity to light elements (e.g., H, Li) 

and deep penetration into bulk materials, SANS enables quantitative analysis of pore morphology, interfacial structure, and 

phase behavior across length scales of 1–300 nm. This review presents a comprehensive overview of SANS applications 

in lithium-ion, lithium–sulfur, lithium–metal, all-solid-state, sodium-ion, and metal–air battery systems. We highlight how 

advanced modeling approaches—such as contrast variation, Teubner–Strey, Guinier–Porod, and DAB models—facilitate the 

interpretation of complex nanostructures. Particular emphasis is placed on operando SANS studies, which ofer real-time 

insight into dendrite formation, solid-electrolyte interphase evolution, and ion-storage dynamics, underscoring the growing 

importance of SANS in electrochemical energy research. This review aims to serve as a practical and conceptual guide for 

researchers seeking to apply SANS to battery systems, ofering key strategies and perspectives for future materials design 

and mechanistic studies.