Room temperature ionic liquids (RTILs) are comprised of bulky organic cations and anions. Because of the intricate interplay of various inter- and intramolecular interactions, RTILs have rich dynamical properties and have found diverse applications in many areas, including green chemistry and energy applications. In this talk I will discuss our recent studies on structural and dynamical properties of RTILs and their applications as energy storage materials, based upon statistical mechanical theory and molecular dynamics (MD) simulations. In the first part, we present an overview on our recent MD studies of dynamics of RTILs employing a coarse-grained model of 1-ethyl-3-methylimidazolium hexafluorophsphate. In particular, we describe the nature of glassy dynamics and dynamic heterogeneity that are observed in the RTILs based upon our coarse-grained model. In the second part, we investigate the possible application of RTILs as energy storage material. Energy density and power density of supercapacitors based on graphene electrodes studied via MD simulations. Two electrolytes of different types, pure 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI+BF4-) and an solution of EMI+BF4- in acetonitrile, are considered as a prototypical room- temperature ionic liquid (RTIL) and organic electrolyte, respectively, and their performances are compared.