fig6

Figure 6. (A) Schematic illustration of the different shape evolution paths for hollow structures. Grey, yellow, and blue represent carbon, insoluble component, and dissolvable component, respectively. Copyright 2017, Journal of the American Chemical Society^[48]. (B) Schematic illustration for the large-scale fabrication of hierarchically porous nitrogen-doped carbon microspheres. (C-E) The electronic density differences of K⁺ ion adsorbed on pristine carbon, GN-doped carbon, and PN-doped carbon, respectively. (F) The density of states of corresponding carbon materials. Copyright 2017, Energy Storage Materials^[49].