Peyghan Ali Ahmadi, Beheshtian Javad
Chemistry Department, Faculty of Sciences, Shahid Rajaee Teacher Training University, 16785-163, Tehran, Iran.
Chemistry Department, Faculty of Sciences, Shahid Rajaee Teacher Training University, 16785-163, Tehran, Iran.
J Mol Graph Model. 2020 Jul;98:107578. doi: 10.1016/j.jmgm.2020.107578. Epub 2020 Mar 13.
The effect of the Stone-Wales (SW) defect on the energetic, structural, electronic properties of Na/Na adsorption on the Hexa-peri-hexabenzocoronene (HBC) nanographene is investigated using density functional theory calculations. We showed that two kinds of SW defects can be generated in the structure of HBC, and the defected sheets are less stable than the intrinsic HBC by about 63.2-65.3 kcal/mol. The heptagonal ring of SW defect is the most favorable site for the Na and Na adsorption and the adsorption energies increase from -0.8 and -33.2 kcal/mol on the intrinsic HBC to -16.7 and -39.3 kcal/mol on the SW-HBC, respectively. The predicted energy barrier for an Na atom to move from a heptagonal ring to another one in the SW-HBC is about 4.9 kcal/mol, indicating a high ion mobility compared to the pristine HBC. The SW defect increases the Na diffusion coefficient from 3.46 × 10 to 2.83 × 10 cm/s. Although the SW defect increases the ion mobility, it has an undesirable effect on the cell voltage, if a HBC nanographene is used in the anode of Na-ion batteries.
利用密度泛函理论计算研究了斯通-威尔士（SW）缺陷对六重周边六苯并蔻（HBC）纳米石墨烯上钠/钠吸附的能量、结构和电子性质的影响。我们发现HBC结构中可产生两种SW缺陷，有缺陷的片层比本征HBC稳定性低约63.2 - 65.3千卡/摩尔。SW缺陷的七元环是钠和钠吸附的最有利位点，吸附能分别从本征HBC上的-0.8和-33.2千卡/摩尔增加到SW - HBC上的-16.7和-39.3千卡/摩尔。预测在SW - HBC中一个钠原子从一个七元环移动到另一个七元环的能垒约为4.9千卡/摩尔，表明与原始HBC相比具有较高的离子迁移率。SW缺陷使钠扩散系数从3.46×10增加到2.83×10厘米²/秒。虽然SW缺陷增加了离子迁移率，但如果将HBC纳米石墨烯用于钠离子电池的阳极，它会对电池电压产生不良影响。
