fig6
Figure 6. DFT calculations: (A-D) The theoretical calculation models with top- (upper) and side-view (lower) for K+ absorbed on different models as well as corresponding Ead (purple, grey, blue, red, and white colors indicate K, C, N, O, and H atoms). (E and F) Densities of state (DOS) of pure C and N/O co-doped C.
