fig5

Figure 5. Differentiation of capacitive and diffusion-controlled contribution from CV curves at 5 mV s^-1 for (A) S-ATrGO/CG; (B) S-OrGO/CG; (C) Capacitance contribution calculation from CV curves of 5 mV s^-1; (D) CV curves of S-ATrGO/CG and NS-ATrGO/CG at a scan rate of 25 mV s^-1; (E) Specific capacitance from CV plots with variation of scan rates; (F) Comparison of GCD curves at a current density of 5 mA cm^-2; (G) The Nyquist plots measured in a frequency range between 0.01 and 10⁵ Hz. (inset: the enlarged high-frequency region); (H) The specific capacitance retention and coulombic efficiency with 20,000 cycling numbers; (I) The GCD curves from the first cycle and the last cycle. EDLC: Electric double layer capacitance; CV: cyclic voltammetry; CG: commercial graphene; ATGO: acid-treated graphene oxide; S-ATrGO: sulfuric acid-treated reduced graphene oxide; NS: non-slit; GCD: galvanostatic charge-discharge; RHE: reversible hydrogen electrode.