Optimizing the Structure/Texture Coupling of Carbon Xerogels for High‐Performance Anodes of Sodium‐Ion Batteries in Glyme‐Based Electrolytes

Carbon xerogels with a pore size of approximately 500 nm, synthesized through an energy‐efficient microwave‐assisted process and subsequently thermally treated at temperatures ranging from 1000°C to 2800°C, are investigated as anodes in sodium‐ion batteries using a glyme‐based electrolyte. The present study focuses on determining the optimal balance between the textural and structural properties of the resulting materials to enhance their electrochemical performance. Particular attention is paid to the material interlayer spacing and porosity, aiming to achieve a suitable compromise between ordered and disordered carbon structures. This balance is crucial to maximize the electrochemical storage of the Na + ions in the materials via surface adsorption (defects, pores), insertion/intercalation/co‐intercalation into the aromatic layers of graphitic domains, and/or nanopore filling mechanisms. Among the carbon xerogels studied, CX500‐1800 which features very low surface area, an almost negligible micropore volume, and an interlayer spacing of approximately 0.37 nm emerged as the most suitable candidate for this application. This material delivers a capacity of 233 mAh g⁻¹ after 200 cycles at 37.2 mA g⁻¹ with a coulombic efficiency of 94%. The enhanced performance of this carbon material suggests a synergistic effect of its optimized textural and structural properties. Specifically, the absence of microporosity minimizes irreversible sodium trapping, while the moderate increase in the structural order—achieved through thermal treatment at 1800°C—facilitates efficient Na⁺ ion transport and storage mainly through intercalation into the graphitic domains.