Anodic TiO2 nanotubes as anode electrode in Li–air and Li-ion batteries

We investigate the possibility of using a TiO2 anode as an alternative to the Li electrode in Li–air and Li-ion rechargeable batteries. TiO2 nanotube layer is fabricated by the anodization method and optional thermal treatment is conducted. The electrochemical charge/discharge profile of the TiO2/liquid electrolyte/LiCoO2 structured cell is measured under the flowing of O2, N2 and Ar, respectively. The elevation of the upper cut-off voltage from 3 to 4.5 V leads to an increase in the specific capacity by a factor of more than three. We suppose this to be a novel mechanism in which the TiO2/LiCoO2 system under the oxygen atmosphere works in Li–air battery mode up to 3 V and then works in Li-ion battery mode from 3 V to 4.5 V. This idea is confirmed by ICP-OES analysis.