Ultra-thin anatase TiO2 nanosheets with admirable structural stability for advanced reversible lithium storage and cycling performance

- The ultra-thin anatase TiO2 nanosheets are facilely synthesized.
- The obtained structure exhibits an enlarged electrode/electrolyte interfacial area.
- The structure proves to facilitate short electron transfer and lithium ion diffusion paths.
- The superior structural stability during lithium ion insertion/extraction process results in an excellent cycling performance.

Anatase TiO2 ultra-thin nanosheets (TiO2-NS) are synthesized by a facile hydrothermal method. Several merits are realized when employing the prepared TiO2-NS as lithium ion battery anode material, compared to TiO2 nanoparticles. Firstly, the as-prepared TiO2-NS has high charge capacities and a specific surface area up to 98.8 m2g−1, which is beneficial for the insertion of lithium ion. Secondly, the large specific surface area is helpful in enlarging the electrode/electrolyte interfacial area. Finally, the EIS result verifies short electron transfer paths. More importantly, the stability of the nanosheet structure is indirectly confirmed by the excellent cycling performance of charge capacity and the curve of charge capacities versus cycle number at different current densities. After galvanostatic charge/discharge of the batteries for 1000 cycles, the HRTEM images of post-mortem batteries directly reveal a good reversibility of the lithium ion insertion/extraction process aided by TiO2-NS. Thus, all these advantages and the special structure facilitate an excellent cycling performance: the charge capacity with the maximum value of 250 mAh g−1 keeps half after 2000 cycles at a current density of 840 mA g−1 (5 C).

In this work, ultrathin anatase TiO2 nanosheets have been facilely &z.rtrif; synthesized. On account of the structural stability, coin-cell employing &z.rtrif; the nanosheet electrode achieves an excellent cycling performance: the &z.rtrif; charge capacity with the maximum value of 250 mAh g−1 keeps half after 2000 cycles at a current density of 840 mA g−1 (5 C).85