To identify the crystal structures, high-power powder X-ray diffraction (HP-PXRD) data were obtained on Rigaku X-ray diffractometer (3 phase, 380 V, 18 kW) equipped with Cu Kα radiation (λ = 1.54 Å) in the 2θ range of 10-80°. The XRD samples were prepared by depositing a thick film of cathode powder on a glass substrate. To reveal the morphology and chemical composition of samples a JEM-2200FS (Cs corrected STEM) HRTEM coupled with an energydispersive X-ray spectrometer (EDX, Oxford-INCA) at an acceleration voltage of 200 kV was used. Samples for the HRTEM analysis were prepared following a conventional standard procedure by dispersing in ethanol and then sonicating for a while. The well-dispersed suspension was dropped on TEM Cu-grid and oven-dried to use for HRTEM analysis.