fig6

Figure 6. K⁺ adsorption on the surface of undoped, O-species and N-species doped carbon. (A) Adsorption of K⁺ on an ideal carbon surface (Precursor); (B-D) K⁺ adsorption on carbon surfaces doped with different O-doping functional groups; (E-G) Adsorption model of K⁺ on doped surfaces with different N functional groups.