One-pot synthesis of nitrogen-doped carbon aerogels derived from sodium lignosulfonate embedded in carrageenan for supercapacitor electrode materials

Abstract

Nitrogen doping of carbon materials can enhance the electrical conductivity, surface wettability, and introduce pseudocapacitance to improve the performance of supercapacitors. We propose a cost-effective and eco-friendly one-pot strategy to prepare high nitrogen-containing carbon aerogels from biomass, with soybean protein isolate as a nitrogen source, sodium lignin sulfonate as a carbon source, and carrageenan with thermal reversible gel properties as a gel skeleton. The surface morphology and porous structure of the carbon aerogel are analyzed by scanning electron microscopy (SEM) and nitrogen adsorption–desorption, which indicates the macro-, meso-, and microporous structure (hierarchical porous structure) of carbon aerogel. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), and Raman spectroscopy are used to analyze the functional groups and degree of graphitization of the material with a nitrogen content of 6.18 at.% from pyrrole, pyridine and graphite nitrogen. The specific capacitance of the carbon aerogel is up to 231.75 F/g at a current density of 0.5 A/g, and the capacitance retention reaches 85.7 % after 5000 cycles. This work provides a novel strategy to prepare high nitrogen-containing carbon aerogels from biomass for high-performance supercapacitors with the concept of utilizing renewable biomass efficiently and sustainably.