The opposite consequence is captured for the charged PBs with large grafting density, see Figure (a) and (c). According to the figures in the right panel of Figure , most counterions distributes among the entire PB layer. Especially, the uncrowded space adjacent to the surface (which has been mentioned in the Case I) is occupied by the counterions. This finding suggests the great potential of charged PBs as the porous interfacial energy-storage layer.