Abstract:

Activated carbons prepared by conventional processes have sufficient micropores but lack medium and large pore contents, resulting in low levels of electrochemical performance when used as electrode materials for supercapacitors. To solve this problem, hydrochloric acid was used to pretreat the enteromorpha raw material before charring. The acid treatment removed most of the impurity metals from the raw material, in which calcium alginate reacted chemically with hydrochloric acid to form eggshell initial pores and acid-soluble alkali metal ions reacted with hydrochloric acid to form irregular initial pores, significantly increasing the mesoporous content of the activated carbon. The experimental results showed that the specific surface area of activated carbon increased significantly after hydrochloric acid pretreatment from 2273m²/g to 3166m²/g and the pore volume increased from 2.10cm³/g to 3.82cm³/g. The mesoporosity increased significantly, improving the connectivity of the pore structure and promoting the diffusion of electrolyte ions within the material. When the current density was 0.1A/g, the specific capacitance of the acid-washed activated carbon was as high as 359F/g, an increase of 23% over the 293F/g specific capacitance of the as-built activated carbon, and the capacitor equivalent series resistance was very small, showing excellent electrochemical performance.

Key words: biomass, activated carbon, supercapacitor, hydrochloric acid pretreatment, electrochemical performance

摘要：

传统工艺制备的活性炭微孔足够，但中孔、大孔含量缺乏，导致其用作超级电容器电极材料时电化学性能水平较低。为解决这一问题，采用盐酸对炭化前浒苔原料进行预处理。酸处理去除了原料中大部分的杂质金属，其中，海藻酸钙与盐酸发生化学反应形成了蛋壳初始孔，酸溶性碱金属离子与盐酸发生置换反应形成了无规则初始孔隙，明显增加了活性炭的中孔含量。实验结果表明：盐酸预处理后的活性炭比表面积明显增加，由2273m²/g增至3166m²/g，孔容由2.10cm³/g增至3.82cm³/g，中孔率显著提高，改善了孔结构的连通性，促进了电解质离子在材料内部的扩散；当电流密度为0.1A/g时，经过酸洗处理的活性炭比电容高达359F/g，比原样活性炭比电容的293F/g增长了23%，超级电容器等效串联电阻很小，表现出良好的电化学性能。

关键词: 生物质, 活性炭, 超级电容器, 盐酸预处理, 电化学性能