Morphologies of electrodes were measured on a cold field scanning electron microscope (SEM, HITACH-S4800, SU8010). XRD was performed using a Bruker D8 Advance diffractometer equipped with a Cu Kα radiation source (λ1 = 1.54060 Å, λ2 = 1.54439 Å at 40 kV and 40 mA). Rietveld refinement of the XRD was carried out using the General Structure Analysis System software with the EXPGUI software interface. TEM experiments were performed on a STEM (JEM-ARM300F, JEOL) operated at 300 kV with a cold field emission gun and double Cs correctors.