642915.fig.004a
(a)
642915.fig.004b
(b)
642915.fig.004c
(c)
642915.fig.004d
(d)
Figure 4: (a) N-doped and (b) B-doped graphene electrodes obtained over a wide range of current densities, from 0.5 to 25 Ag−1; (c) schematic structure of the binding conditions of N and B in a graphene lattice; (d) Ragone plots for the pristine graphene, N-doped grapheme, and B-doped grapheme [27].