Nat Mater. 2012 Mar 4;11(4):306-10. doi: 10.1038/nmat3260.
Lightweight, low-cost supercapacitors with the capability of rapidly storing a large amount of electrical energy can contribute to meeting continuous energy demands and effectively levelling the cyclic nature of renewable energy sources. The excellent electrochemical performance of supercapacitors is due to a reversible ion adsorption in porous carbon electrodes. Recently, it was demonstrated that ions from the electrolyte could enter sub nanometre pores, greatly increasing the capacitance. However, the molecular mechanism of this enhancement remains poorly understood. Here we provide the first quantitative picture of the structure of an ionic liquid adsorbed inside realistically modelled microporous carbon electrodes. We show how the separation of the positive and negative ions occurs inside the porous disordered carbons, yielding much higher capacitance values (125 F g(-1)) than with simpler electrode geometries. The proposed mechanism opens the door for the design of materials with improved energy storage capabilities. It also sheds new light on situations where ion adsorption in porous structures or membranes plays a role.
具有快速存储大量电能能力的轻量级、低成本超级电容器可以有助于满足持续的能源需求，并有效地平衡可再生能源的循环性质。超级电容器的优异电化学性能归因于多孔碳电极中可逆的离子吸附。最近，已经证明电解质中的离子可以进入亚纳米级孔隙，从而大大提高了电容。然而，这种增强的分子机制仍未得到很好的理解。在这里，我们提供了第一个定量的图像，展示了吸附在实际模拟微孔碳电极中的离子液体的结构。我们展示了正离子和负离子如何在多孔无序碳内部分离，从而产生比具有更简单电极几何形状更高的电容值（125 F g(-1)）。所提出的机制为设计具有改进储能能力的材料开辟了道路。它还为在多孔结构或膜中吸附离子的情况提供了新的见解。
