| 초록 |
Electric double layer capacitors (EDLCs) are rechargeable and have high power density, thus has been researched as a complementary energy storage devices other than batteries. To increase the energy density of EDLCs, room temperature ionic liquids (RTILs) has been utilized as an electrolyte of EDLCs because of their electrochemical stability. Experimental and MD simulation studies have shown that the confined electrode structures can enhance the capacitance of EDLCs. However, the cost of experiments and MD simulations are much higher than solving partial differential equation for studying the effect of several parameters of EDLCs. In this study, the double layers of RTILs in nanostructure electrodes are simulated by solving the modified Poisson-Boltzmann equations, which considers steric effect and overscreening effect of ionic liquids. By simulating nanoslit and cylindrical nanopores of several sizes, our study shows that the overscreening effect between the electrolytes can be much reduced in confined geometry, which results in the capacitance enhancement. The specific capacitances and charge density distributions normal to electrodes are analyzed to support the conclusion. |
