An integrated synthesis strategy with dual-functional solvent for in situ N/O-doped carbon aerogels enabling high supercapacitor performance

The rational design of biomass-derived carbon aerogels is crucial for developing high-energy-density supercapacitors. Herein, we report a one-pot synthesis of in situ N/O dual-doped porous carbon aerogels from cotton fibers, utilizing a NaOH/urea aqueous system as a multifunctional solvent, followed by freeze-drying and carbonization. The optimized cotton fiber-derived carbon aerogel (HCFA-600) possesses a high specific surface area (398.4 m² g⁻¹), a honeycomb-like pore architecture, and significant heteroatom doping. When tested in a three-electrode system, the HCFA-600 electrode achieves a notable specific capacitance of 249 F g⁻¹ at 1 A g⁻¹. A symmetric coin-type supercapacitor (HCFA-600//HCFA-600) assembled using this material delivers a high energy density of 14.5 Wh kg⁻¹ at a power density of 500 W kg⁻¹, while retaining 75.58% of its initial capacitance after 5,000 cycles at 5 A g⁻¹. The proposed synthesis route, which enables in situ heteroatom doping of porous carbon aerogels from renewable cotton fibers, is not only simple, eco-friendly, and cost-effective but also holds promising potential for application in high-performance supercapacitors.