Nanocellulose based nitrogen-doped carbon/Ni-Co layered double hydroxide composite aerogels for high-performance supercapacitor electrodes

To enhance the electrochemical performance of flexible electronic devices, it is crucial to develop electrode materials with high specific capacitance. The nitrogen-doped carbon aerogel (CA) was synthesized through freeze-drying and carbonization of TEMPO-oxidized cellulose nanofibril aerogel. Inspired by porous media interface strategies, a nitrogen-doped carbon/ nickel-cobalt (Ni-Co) layered double hydroxide composite aerogel (CA-N@LDH) with a hierarchical porous structure was fabricated using a solution deposition method with controlled precursor concentration. X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterization confirmed that the Ni-Co layered double hydroxides were uniformly loaded on the surface of the mesoporous carbon framework in a flower-like layered structure, achieving a specific surface area of 111.8 m²/g and pore size mainly of around 5 nm. When the addition of the precursor was 0.4 mmol, the composite exhibited a specific capacitance of 1892.7 F/g at a current density of 1 A/g, which represents a 6.7 times enhancement compared with pure nitrogen-doped (N-doped) carbon aerogel. X-ray photoelectron spectroscopy (XPS) analysis revealed the synergistic pseudocapacitive contributions from the Co²⁺/Co³ ⁺ and Ni²⁺/Ni³ ⁺ redox pairs, while the graphite-like N introduced by N doping reduced the charge transfer resistance by 42%. This study provides new insights into the design of composite electrodes with high specific capacitance and stability.