Figure 7

Electrochemical impedance spectra at 55 °C for uncoated LiMn_1.5Ni_0.5O₄ particles and coated with various thicknesses of iron oxide after (a) 1^st cycle and (b) 1,000^th charge-discharge cycles. Inset images show the high frequency regions (1M Hz–100 Hz) of the impedance spectra.