Materials characterizations: TGA analysis was conducted on a thermogravimetric analyzer (STA 449F3) in flowing N 2 at 5 °C min -1 ramping rate from 50 °C to 500 °C. Chemical compositions were characterized by elemental analysis (EuroEA3000 elemental analyzer) for O and H, and by ICP-MS (IRIS Intrepid II XSP) for Li and Ti. FTIR spectra were obtained by Bruker spectrometer (VERTEX 70V) at 500~4000 cm -1 . XRD data were collected on Bruker D8 Advance X-ray diffractometer with Cu Kα (λ=0.154 nm). SEM images were taken on ZEISS microscopy (Gemini 2) and HRTEM images on JEOL microscopy (JEM-2100F).