The theoretical principle of choosing suitable room temperature ionic liquids (RTILs) for liquid phase exfoliation of graphene sheet remains a challenge. A simple thermodynamic model is proposed to show the vital role of the solvation energy as an indication of solvent quality for spontaneous exfoliation. The solvation energy of ten ILs surrounding a single graphene sheet has been determined by molecular dynamics (MD) simulations. It is found to be strongly correlated with surface excess, sheet deformation and surface tension. From the MD simulations [BMIM][TF2N] (-580.86 mJ.m−2), [BPY][ TF2N] (-565.19 mJ.m−2) and [BMP][TF2N] (-551.77 mJ.m−2) shows stronger affinity with graphene surfaces as compared to other ILs. On the basis of the established mechanism, one is able to predict and screen suitable IL for spontaneous exfoliation of graphene. © 2021 Elsevier B.V.