Secondary energy storage technologies based on sodium ions are an important emerging alternative to lithium ion batteries. Sodium is less expensive than lithium, with its supplies being much wider and more democratically distributed throughout the globe. Therefore there is the potential for significantly reduced system cost, as well as for increased energy security due to ease of obtaining sodium precursors. A survey of literature indicates that the most optimum negative electrodes for sodium ion capacitors (NICs) consist of high surface area two-dimensional carbons, such as various high surface area carbon nanosheets. However, to date, fast Na charge storage mechanisms in such carbons are not well understood. In this talk, we will present the adsorption and transport characteristic of Na ion and electrolytes (EC/DMC) at the interface and discuss how Na is reversibly and irreversibly stored within imperfect carbons using combined molecular dynamics and density functional theory calculations. For example, our recent study suggests that N-doping leads to significant enhancement in Na adsorption which could lead to Na trapping. We will discuss the fundamental issues regarding the Na ion storage behavior at the interface with varying carbon ordering and heteroatom chemistry, and the design principles to enhance Na based energy storage and charge rate.