• A comprehensive dataset of hard carbon anodes for sodium-ion batteries is presented, including electrochemical performance and structural characterization.
• SAXS fitting provides detailed structural parameters that correlate with electrochemical performance, enabling microstructure analysis of closed pores and carbon layers.
• The dataset enables comparative analysis of structure-performance relationships, facilitating optimization of hard carbon materials for sodium-ion batteries.
• Data includes capacity performance, structural data, and SAXS fitting results, with raw and analyzed formats accessible for further studies.