fig3

Figure 3. (A) Synthesis routes for NS-TiO₂; (B) Long-term cycle performance of TiO₂ and NS-TiO₂. Quoted with permission from Fan et al.^[48]; (C) Synthesis routes for different TiO₂ spheres, and their corresponding (D) Initial charge/discharge profiles and (E) Long-term cycling performance. Quoted with permission from Xu et al.^[54]; (F) Synthetic routes for C-NTO and C-NTC microspheres; (G) Cycling stability and (H) Rate performance of C-NTO. Quoted with permission from Meng et al.^[55]; TiO₂-HS: TiO₂ hollow spheres formed by smaller nanosheets; TiO₂-YB: TiO₂ yolk-like spheres with bigger nanosheets; TiO₂-S: amorphous TiO₂ solid spheres; TTIP: tetra-n-butyl titanate; NS-TiO₂: N and S double doping method to achieve highly doped anatase-type titanium; NTO: Na₂Ti₃O₇; NTC: titanate/titanium.