Fig. 4: Simulation study on the water affinity towards cation intercalated graphitic nanochannels in a model bilayer graphene.

a Schematic diagram of the simulation cell at initial state (0 ps) in ab initio MD simulation. The supercell consists of a graphitic sheet (grey spheres) intercalated with two cations (violet spheres) and filled with water molecules (red and white spheres are oxygen and hydrogen atoms, respectively). The periodic boundary conditions ensure the nanoconfinement. The dimension of the simulation cell is x = 17.23 Å, y = 17.05 Å and z = 14 Å. b Distribution of water molecules at the initial state. Violet circles are the position of cations. x is a placeholder for different types of cations. The number of accumulated water molecules is represented by the colour range in the scale. c–e Distribution of water molecules after 4 ps for graphitic sheets intercalated with K⁺, Na⁺ and Ca²⁺ ions, respectively. Source data are provided as a Source Data file.