High specific surface area carbon aerogel derived from starch for methylene blue adsorption and supercapacitors.

Starch based carbon aerogel has attracted significant attention due to the wide source, environmental friendliness and low price of raw materials. Here, starch based carbon aerogel was fabricated by graft reaction and cross-linking reaction of starch. The network structure of starch hydrogel was optimized through graft and cross-linking reaction. After freeze drying and high temperature carbonization, the obtained carbon aerogel that carbonized at 800 °C showed a specific surface area of 1508 m2·g-1 without activation which is far higher than that of other unactivated carbon aerogels. The starch based carbon aerogel carbonized at 800 °C exhibited superior methylene blue adsorption ability with a maximum adsorption capacity of 963.5 mg·g-1 as a result of its rich surface functional groups, high specific surface area, and reasonable pore size distribution. Furthermore, the carbon aerogel carbonized at 700 °C exhibited excellent electrochemical performance with a specific capacitance of 180.1 F·g-1 at a current density of 1 A·g-1as electrode materials for supercapacitors. Overall, this work provides a new method to prepare high performance starch based carbon aerogel.

Starch-based carbon aerogels prepared by an innovative KOH activation method for supercapacitors.

Biomass-based carbon aerogels hold promising application prospect in the field of supercapacitors. In this research, starch was selected as a raw material for preparing carbon aerogels. The preparation process of starch hydrogels was simplified by using KOH, which can change starch suspension into hydrogels at room temperature. Moreover, the molecular mixing of KOH and starch was realized, so that KOH can be fully utilized in the activation process. The specific surface area of the starch-based carbon aerogels prepared by this method was 1349 m2/g, and the proportion of micropores was 43.7 %. Remarkably, as electrode materials for supercapacitors, the starch-based carbon aerogels exhibited outstanding electrochemical performance. In a three-electrode system, the carbon aerogels exhibited specific capacitance of 211.5 F/g at 0.5 A/g and 138.5 F/g at 10 A/g, suggesting their suitability for high-current applications. In a symmetrical supercapacitor configuration, the materials exhibited an energy density of 11.3 Wh/kg at a power density of 0.5 kW/kg and the specific capacitance can maintain 98.91 % after 10,000 cycles. Overall, this work provides a new method for mixing activators, which will foster potential advances in starch based carbon aerogels.