Green Synthesis of Porous Honeycomblike Carbon Materials for Supercapacitor Electrodes

Gel precursors based on molecular-modification are becoming a promising strategy for the construction of functional carbon materials. In this paper, sodium alginate was used as a carbon precursor to get insoluble gels by introducing Ca2+, and then, 3-dimensional porous honeycomblike carbon materials were prepared by the following one-step carbonization process. The influence of the heating rate for the morphology, porous structure, and electrochemical performance of the sample was also discussed. The sample prepared at a heating rate of 6 °C/min possessed the ideal architecture and the best electrochemical performance. The honeycomblike framework consisted of many interconnected bubblelike units, being an open and unimpeded structure, which can reduce the migration resistance of electrolyte in the carbon materials. The capacitance of the sample prepared with a heating rate of 6 °C/min is 339 F/g at 1 A/g. It can also maintain almost 85% when the current density is up to 20 A/g, and the sample also exhibits a low diffusion resistance of electrolyte and excellent cycling stability. This research establishes new links among environmental improvement, biomass conversion, and renewable energy utilization.