Bottom‐Up Synthesis of Advanced Carbonaceous Anode Materials Containing Sulfur for Na‐Ion Batteries

Abstract The fabrication of sulfur‐containing carbonaceous anode materials (CS) that show exceptional activity as anode material in Na‐ions batteries is reported. To do so, a general and straightforward bottom‐up synthesis of CS materials with precise control over the sulfur content and functionality is introduced. The new synthetic path combined with a detailed structural analysis and electrochemical studies provide correlations between i) the sulfur content and chemical species and ii) the structural, electronic, and electrochemical performance of the associated materials. As a result, the new CS substances demonstrate excellent activity as Na‐ion battery anode materials, reaching capacity values above 500 mAh g⁻¹ at a current density of 0.1 A g⁻¹, as well as high reversible sodium storage capabilities and excellent cycling durability. The results reveal the underlying working principles of carbonaceous materials, alongside the storage mechanism of the Na⁺ ions in these advanced sodium‐ion battery anode materials and provide a new avenue for their practical realization.