fig6

Figure 6. (A) Cyclic voltammetry of CeO₂@void@C at a scan rate of 0.1 mV·s^-1 at room temperature. (B) Cycling performance of CeO₂@void@C. (C) Rate performance of untreated CeO₂ and CeO₂@void@C under different applied current densities, whose values are marked in columns in mA·g^-1. (D) Nyquist impedance curves for the untreated CeO₂ and CeO₂@void@C materials. (E) Long life cycling performance of CeO₂@void@C under a current density of 0.1 A·g^-1.