Galib Musanna, Hosen Mohammad Mozammal, Saha Joyanta K, Islam Md Mominul, Firoz Shakhawat H, Rahman Md Ashiqur
Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
Chemistry Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, Dhaka, 1000, Bangladesh.
J Mol Model. 2020 Aug 24;26(9):251. doi: 10.1007/s00894-020-04483-5.
In this study, molecular dynamics (MD) simulations have been performed to explore the variation of ion density and electric potential due to electrode surface modification. Two different surface morphologies, having planer and slit pore with different conditions of surface charge, have been studied for graphene-MnO surface using LAMMPS. For different pore widths, the concentration of ions in the double layer is observed to be very low when the surface of the graphene-MnO electrode is charged. With a view to identify the optimal pore size for the simulation domain considered, three different widths for the nano-slit type pores and the corresponding ion-ion interactions are examined. Though this effect is negligible for pores with 9.23 and 3.55 Å widths, a considerable increase in the ionic concentration within the 7.10 Å pores is observed when the electrode is kept neutral. The edge region of these nano-slit pores leads to effective energy storage by promoting ion separation and a significantly higher charge accumulation is found to occur on the edges compared to the basal planes. For the simulation domain of the present study, partition coefficient is maximum for a pore size of 7.10 Å, indicating that the ions' penetration and movement into nano-slit pores are most favorable for this optimum pore size for MnO-graphene electrodes with aqueous NaCl electrolyte. Graphical Abstract The importance of understanding the commercial feasibility of supercapacitor material has made qualitatively predicting the optimized electrode structure one of the main targets of energy related researches. While great progress has been made in recent years, a coherent theoretical picture of the optimized electrode structure remains elusive. This article discusses the most favorable design of supercapacitor electrode for ion-electrode interaction.
在本研究中，已进行分子动力学（MD）模拟，以探索由于电极表面改性导致的离子密度和电势变化。使用LAMMPS对具有不同表面电荷条件的平面和狭缝孔这两种不同表面形态的石墨烯 - 二氧化锰表面进行了研究。对于不同的孔径，当石墨烯 - 二氧化锰电极表面带电时，观察到双层中离子的浓度非常低。为了确定所考虑模拟域的最佳孔径，研究了三种不同宽度的纳米狭缝型孔及其相应的离子 - 离子相互作用。尽管对于宽度为9.23 Å和3.55 Å的孔，这种影响可以忽略不计，但当电极保持中性时，在宽度为7.10 Å的孔内观察到离子浓度有相当大的增加。这些纳米狭缝孔的边缘区域通过促进离子分离导致有效的能量存储，并且发现与基面相比，边缘上发生的电荷积累明显更高。对于本研究的模拟域，孔径为7.10 Å时分配系数最大，这表明对于含NaCl水溶液电解质的MnO - 石墨烯电极，离子渗透并进入纳米狭缝孔对于该最佳孔径最为有利。图形摘要了解超级电容器材料商业可行性的重要性使得定性预测优化的电极结构成为能源相关研究的主要目标之一。尽管近年来已经取得了很大进展，但优化电极结构的连贯理论图景仍然难以捉摸。本文讨论了用于离子 - 电极相互作用的超级电容器电极的最有利设计。
