An interlayer defect promoting the doping of the phosphate group into TiO(B) nanowires with unusual structure properties towards ultra-fast and ultra-stable sodium storage

Heteroatom doping is an effective way to modulate the local structure of TiO 2 -based materials, enabling enhanced electrochemical performance. However, current studies generally adopt a single atom doping strategy, and ionic group doping has rarely been achieved and is a distinctly bigger challenge. Herein, doping of the phosphate group at high concentrations into blue TiO 2 (B) nanowires is proposed and realized for the first time by skillfully utilizing the defects induced during the dehydration and topology transformation process of the H-titanate precursor; based on experimental characterization and first-principles calculations, it has been demonstrated that this material possesses exceptional electrical properties, a remarkably reduced band gap, magnetic characteristic from the extra electrons outside the Ti atomic nucleus and remarkable phase stability. Benefiting from the unusual structure properties, phosphate-doped TiO 2 (B) exhibits the ultra-fast sodium storage capability of 124 mA h g −1 at the extremely high rate of 50 A g −1 and excellent long cycling stability even at 10 A g −1 after 5000 cycles. Moreover, this electrode material was tested at low temperatures and exhibited comparable reversible capacity and outstanding cycling stability to those at normal temperatures. We also assembled a B-TiO 2 (B)-P//(NVPF) full cell, which delivered the maximum energy density of 170 Wh kg −1 and the maximum power density of 5000 W kg −1 . Phosphate group-doped blue TiO 2 (B) nanowires were first achieved, exhibiting ultra-fast and ultra-stable sodium storage.