Rational Design of N-Doped Carbon Aerogel with Well-Defined Micropore Structure to Adsorb Dye from Water for High-Performance Lithium-Ion Battery Cathodes

N-doped carbon aerogels have garnered increasing research interest in the field of energy and environment due to their unique structural features. Organic dyes, which contain redox-active sites and act as pollutants, are attractive candidates for cathode materials in Li-ion batteries but still suffer from poor cycle stability and rate performance. Therefore, there is still a lack of an easy and effective approach to rationally design the pore structure of N-doped carbon aerogels for efficiently and stably trapping dye molecules and converting them into high-performance cathode materials. Herein, we propose an innovative strategy for preparing nitrogen-doped carbon aerogels with a well-defined micropore structure (MNCAs) for efficient adsorption of dye molecules, subsequently converting them into high-performance lithium-ion battery cathode materials. MNCAs were synthesized via Schiff-based polymerization using polyhedral oligomeric silsesquioxane (POSS) as a template, resulting in a carbon framework with well-defined micropores. Benefiting from their high specific surface area and well-defined micropore structure, MNCAs exhibited a maximum adsorption capacity at equilibrium of 2273 mg g^-1 for indigo. Notably, the indigo@nitrogen-doped carbon aerogel composite (IDG@MNCAs) exhibits high specific capacity, outstanding cycling stability, and remarkable rate capability. The discharge specific capacity of IDG@MNCAs retains 89% of its capacity (120 mAh g^-1) after 200 cycles at 100 mA g^-1 and maintains 70% capacity retention after 1200 cycles at the higher current density of 1000 mA g^-1, surpassing many recently reported organic cathode materials.