Fig. 3. Electrochemical characterization of MoO_x electrodes.

(A) CV curves (at 10 mV s⁻¹) of Mo foil and MoO_x electrode. Inset is a standard three-electrode system. (B and C) CV curves at different scan rates and GCD curves at different current densities for MoO_x electrode, respectively. (D) Rate capability of MoO_x electrodes obtained from CV and GCD curves. (E) Possible Na⁺ intercalation sites at intralayer and interlayer. (F) Electrochemical stability versus cycling number during 500 cycles (the inset is the typical GCD curves upon cycling). (G) Nyquist plot of MoO_x electrode; the plots were fitted by the proposed model of an electrical equivalent circuit in the inset. Photo credit: Hongwei Sheng, Lanzhou University.