Scalable Preparation\nand Precise Control of Carbon\nMaterials via Molten Salt Liquid Seal Strategy in Air

Revealing\nthe relations between the physical and chemical properties\nof carbon materials with defined composition and structure is an important\ntopic. However, traditional organic carbon precursor-derived carbon\nmaterials lack effective fine-tuning methods due to the uncontrollable\ntemperature changes. Herein, a novel strategy termed a “molten\nsalt liquid seal” is introduced to address this issue. Impressively,\nthe uppermost KBr layer in the provided configuration effectively\ncontains the release of carbon organic precursor at low temperatures\nand forms a protective barrier at high temperatures, thereby inhibiting\nthe oxidation of carbon materials in air. Furthermore, we propose\na corresponding “liquid seal” mechanism by monitoring\nthe temperature-dependent morphological evolution of molten salts\nand carbon materials. Remarkably, the heteroatoms, defects, etc.,\nin the carbon material can be precisely controlled within the range\nof 100 °C and 0.5 h per interval. Moreover, the carbonization\nyield is close to or even higher than that of the conventional process\nunder an Ar atmosphere. We also validate the advantages of the resultant\ncarbon materials as anodes in sodium-ion batteries. This innovative\napproach not only minimizes the reliance of inert atmospheres but\nalso enables the high-yield fabrication of carbon materials in air,\nsignificantly advancing the field toward more sustainable practices.