Design and synthesis of interconnected hierarchically porous anatase titanium dioxide nanofibers as high-rate and long-cycle-life anodes for lithium-ion batteries

We suggest an efficient and simple synthetic strategy to prepare interconnected hierarchically porous anatase TiO₂ (IHP-A-TiO₂) nanofibers by two synergetic effects: phase separation between polymers and relative humidity control during electrospinning. The macro channels formed by polystyrene decomposition were interconnected by numerous mesopores that were formed by evaporation of infiltrated water vapor in the structure. The resulting IHP-A-TiO₂ nanofibers showed better Li⁺ ion storage performances than the TiO₂ materials reported in the literature. The discharge capacity of IHP-A-TiO₂ nanofibers for the 3000^th cycle at 1.0 A g^-1 and corresponding coulombic efficiency from the 20^th cycle onward were 142 mA h g^-1 and >99.0%, respectively. Well-interconnected, ultrafine TiO₂ nanocrystals within the nanofiber showed structural stability during cycling and facilitated facile charge transfer at the electrode-electrolyte interface.