Hollow-structured materials for advanced energy storage and conversion: rational synthesis, multifunctional applications, and mechanism insights

Hollow-structured materials exhibit breakthrough potential in energy storage and conversion, leveraging unique advantages including high specific surface area, controllable cavity architecture, and short-range mass transfer pathways, alongside tunable functional properties. This review synthesizes recent progress, emphasizing the constitutive relationships governing material synthesis, structural engineering, and resultant performance. Key synthesis strategies including encompassing hard-templating, soft-templating, and template-free approaches are delineated with respect to their mechanisms and characteristics. Subsequently, cutting-edge applications in energy storage systems (e.g., lithium-ion batteries, supercapacitors), conversion systems (e.g., photoelectrocatalysis) and the application of partial in-situ testing technology for exploring the reaction mechanism are highlighted. The review concludes by outlining critical challenges and opportunities pertaining to scalable fabrication, structural stability, and device integration, providing a roadmap for the precise design and performance optimization of these materials.