Figure 6

(a,b) Cyclic voltammetric curves of LiMg0.08Mn1.92O4 and LiNi0.03Mg0.08Mn1.89O4 samples in the potential range of 3.6-4.5 V (vs. Li+/Li) at a scan rate of 0.05 mV·s−1 before and after 1000 cycles, (c,d) cyclic voltammetric curves of LiMg0.08Mn1.92O4 and LiNi0.03Mg0.08Mn1.89O4 electrodes at different scan rates, the insets in c and d are the plots of peak current vs. square root of the scan rate.