Kondrat Svyatoslav, Vasilyev Oleg A, Kornyshev Alexei A
Department of Complex Systems , Institute of Physical Chemistry, PAS , Kasprzaka 44/52 , 01-224 Warsaw , Poland.
Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany.
J Phys Chem Lett. 2019 Aug 15;10(16):4523-4527. doi: 10.1021/acs.jpclett.9b01623. Epub 2019 Jul 29.
Progress in low-dimensional carbon materials has intensified research on supercapacitors with nanostructured/nanoporous electrodes. The theoretical and simulation work so far has focused on charging single nanopores or nanoporous networks and the effects due to ionic interactions inside the pores, while the effect of interpore ion-ion correlations has received less attention. Herein, we study how the interactions between the ions in the neighboring pores across the pore walls affect capacitive energy storage. We develop a simple lattice model for the ions in a stack of parallel-aligned nanotubes, solve it by using the perturbation and "semi-mean-field" theories, and test the results by Monte Carlo simulations. We demonstrate that the interpore ionic interactions can have a profound effect on charge storage; in particular, such interactions can enhance or diminish the stored energy density, depending on the sign of like-charge interactions. We also find that charging can proceed either continuously or via a phase transition. Our results call for more detailed investigations of the properties of carbon pore walls and suggest that tuning their electrostatic response may be promising for the rational design of an optimal supercapacitor.
低维碳材料的进展加强了对具有纳米结构/纳米多孔电极的超级电容器的研究。迄今为止，理论和模拟工作主要集中在单个纳米孔或纳米多孔网络的充电以及孔内离子相互作用的影响上，而孔间离子-离子相关性的影响受到的关注较少。在此，我们研究了穿过孔壁的相邻孔中离子之间的相互作用如何影响电容式能量存储。我们为平行排列的纳米管堆叠中的离子开发了一个简单的晶格模型，通过微扰理论和“半平均场”理论求解，并通过蒙特卡罗模拟测试结果。我们证明孔间离子相互作用对电荷存储有深远影响；特别是，这种相互作用可以增强或降低存储的能量密度，这取决于同性电荷相互作用的符号。我们还发现充电可以连续进行或通过相变进行。我们的结果呼吁对碳孔壁的性质进行更详细的研究，并表明调整其静电响应可能有助于合理设计最佳超级电容器。
