Fig. 3. (a) Cycling performance of CeO2 at mV. s-1 in 0.0–3.0 V, (b) Nyquist plots of ac impedance spectra in the frequency range between 0.01100 kHz, (c) The selected
charge-discharge curves of the obtained micro/nano core shell sphere CeO2 as anode materials in lithium-ion cells, (d) The discharge capacity versus cycle number curve for
the as-prepared CeO2.