Wettability and its influence on graphene nansoheets as electrode material for capacitive deionization

► Novel reduction process attaches sulphonic groups to graphene nanosheets. ► Sulphonated graphene nanosheets as electrode material for capacitive deionization. ► Light sulphonation improves the wettability of graphene nanosheets. ► The better wettability improves electrode's electrosorptive capacity.