Molecular dynamics simulations of the electrical double layer on smectite surfaces contacting concentrated mixed electrolyte (NaCl-CaCl2) solutions

► MD simulations of NaCl-CaCl2 electrolyte solutions on smectite clay surfaces. ► Results confirm the existence of three distinct ion adsorption planes. ► Charge inversion occurs in the diffusion ion swarm. ► CaCl+ ion pairs have a high affinity for the clay surface. ► Water and ions diffuse relatively rapidly even near the clay surface.