(591i) Dynamics of Room-Temperature Ionic Liquids Under Nanoscale Confinements

Room-temperature ionic liquids (RTILs) have emerged as excellent electrolytes for supercapacitors in recent years. Their wide electrochemical window allows the operating voltage of supercapacitors to be increased beyond those for convectional electrolytes, thus potentially enhancing both the energy density and power density of supercapacitors. However, the low ionic conductivity of existing RTILs can potentially lead to sluggish charging and discharging of supercapacitors (hence reduced power density), thus compromising one of the key advantages of supercapacitors.

In this work, we investigate the dynamics of RTILs confined in nanopores using molecular dynamics simulations. The transport properties of the ions are quantified as a function of nanopore width and ion densities. These dynamic properties and their dependence on nanopore size are further traced to their unique structure in nanopores with different sizes. The generality of the results and implications for the rational design of porous electrodes and RTILs will be discussed.