以棉秆为生物质源、KOH为活化剂、单质硫为储能物质,采用炭化-活化-高压3步法制备高性能碳硫复合材料,并探究KOH用量对活性碳结构以及复合材料电化学性能的影响。结果表明,KOH的活化促进了活性碳中10 nm以下孔的发育,碳碱质量比(棉秆碳化后的碳:KOH质量比)为1:4时活性碳的比表面积和孔体积达到最大,分别为3 068.15 m²/g和1.68 cm³/g。过量的KOH活化导致3~9 nm部分孔的坍塌,使得微孔/小介孔向大介孔或大孔转化,比表面积和孔体积缩小。复合材料的电化学性能和活性碳的孔体积呈正相关,碳碱质量比为1:4时制备的活性碳与硫进行复合的碳硫复合材料展现出最佳的电化学性能。在0.1 C的电流密度下经过100次循环之后,仍可保留787 mAh/g的放电容量;在2 C的电流密度下也可展现出582 mAh/g的高比容量。

Taking cotton stalk as a biomass source,KOH as an activator,and sulfur as an energy storage material,a high-performance carbon sulfur composite is prepared through a carbonization activation high-pressure three-step method.The effect of changes in KOH dosage on the structure of activated carbon and the electrochemical performance of the composite is investigated.It is indicated from the results that the KOH activation mainly promotes the development of pores with a size below 10 nm in activated carbon.Tthe specific surface area and pore volume of activated carbon reach their maximum,reaching 3 068.15 m²·g^-1 and 1.68 cm³·g^-1,respectively when the ratio of carbon to KOH is 1:4.Excessive KOH activation leads to the collapse of partial pores with a size of 3-9 nm,causing micropores/small mesopores to transform into large mesopores or macropores,further resulting in a reduction in specific surface area and pore volume.The electrochemical performance of the composite shows a positively correlation with the pore volume of activated carbon.The carbon sulfur composite prepared under a carbon/KOH ratio of 1:4 exhibits the best electrochemical performance.The composite can retain a discharge capacity of 787 mAh·g^-1 after it has been reused for 100 cycles at a current density of 0.1 C.At a current density of 2 C,the composite can deliver a high specific capacity of 582 mAh·g^-1.

蒲鹏(1997-),男,硕士生,研究方向为固废处理,ShzPuper@163.com;邓辉(1979-),女,博士,教授,研究方向为固体废弃物资源化利用,通讯联系人,denghky@126.com。