Enhancing Lithium and Sodium Storage Properties of TiO2(B) Nanobelts by Doping with Nickel and Zinc

Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique. It was found that the incorporation of 5 at.% Ni into bronze TiO2 expanded the unit cell by 4%. Furthermore, Ni dopant induced the 3d energy levels within TiO2(B) band structure and oxygen defects, narrowing the band gap from 3.28 eV (undoped) to 2.70 eV. Oppositely, Zn entered restrictedly into TiO2(B), but nonetheless, improves its electronic properties (E-g is narrowed to 3.21 eV). The conductivity of nickel- (2.24 x 10(-8) S center dot cm(-1)) and zinc-containing (3.29 x 10(-9) S center dot cm(-1)) TiO2(B) exceeds that of unmodified TiO2(B) (1.05 x 10(-10) S center dot cm(-1)). When tested for electrochemical storage, nickel-doped mesoporous TiO2(B) nanobelts exhibited improved electrochemical performance. For lithium batteries, a reversible capacity of 173 mAh center dot g(-1) was reached after 100 cycles at the current load of 50 mA center dot g(-1), whereas, for unmodified and Zn-doped samples, around 140 and 151 mAh center dot g(-1) was obtained. Moreover, Ni doping enhanced the rate capability of TiO2(B) nanobelts (104 mAh center dot g(-1) at a current density of 1.8 A center dot g(-1)). In terms of sodium storage, nickel-doped TiO2(B) nanobelts exhibited improved cycling with a stabilized reversible capacity of 97 mAh center dot g(-1) over 50 cycles at the current load of 35 mA center dot g(-1).

Automated summary

Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique, with nickel incorporation expanding the unit cell volume and narrowing the band gap, resulting in enhanced conductivity. Zinc doping improved electronic properties. Nickel-doped mesoporous TiO2(B) nanobelts showed improved electrochemical performance in lithium and sodium batteries.