共价有机骨架/碳纳米管复合材料中锂离子吸附与传输特性的分子模拟

Adsorption and transport properties of the lithium ion in a covalent organic framework/carbon nanotube composite by molecular simulation

利用分子模拟方法对共价有机骨架(covalent organic framework,COF)/碳纳米管(carbon nanotube,CNT)复合材料COF@CNT中锂离子(Li^(+))的吸附与传输特性开展研究,明确了Li^(+)的吸附位点与吸附顺序,得到了相应的吸附能,并观察COF@CNT的表观形貌变化.当达到饱和吸附状态时,COF@CNT的体积变化率仅为0.25,平均电压保持在2.00 V以上,而理论容量则高达1402.47 mAh/g.此外,Li^(+)在COF@CNT内部的电导率大于其在单纯CNT中电导率的实测值.模拟结果可为此类体系的实际应用提供理论基础.

In this study,the adsorption and transport properties of the lithium ion(Li+)in a covalent organic framework/carbon nanotube composite(COF@CNT)are investigated through molecular simulation.The adsorption sites and sequence of Li^(+)are defined and the corresponding adsorption energy is obtained.In addition,apparent change in the morphology of the COF@CNT is identified.When saturated adsorption is reached,the volumetric change rate of the COF@CNT is only 0.25.Simultaneously,the average voltage is maintained at greater than 2.00 V,and the theoretical capacity reaches as high as 1402.47 mAh/g.Finally,the electronic conductivity of Li+inside the COF@CNT exceeds that in a pure CNT.The results of this study can provide a theoretical basis for the practical application of these systems.