Hierarchical assembly of Ti(iv)/Sn(ii) co-doped SnO2 nanosheets along sacrificial titanate nanowires: synthesis, characterization and electrochemical properties

Abstract

Hierarchical assembly of Ti(IV)/Sn(II)-doped SnO₂ nanosheets along titanate nanowires serving as both sacrificial templates and a Ti(IV) source is demonstrated, using SnCl2 as a tin precursor and Sn(II) dopants and NaF as the morphology controlling agent. Excess fluoride inhibits the hydrolysis of SnCl2, promoting heterogeneous nucleation of Sn(II)-doped SnO₂ on the titanate nanowires due to the insufficient oxidization of Sn(II) to Sn(IV). Simultaneously, titanate nanowires are dissolved forming Ti(4+) species under the etching effect of in situ generated HF resulting in spontaneous Ti(4+) ion doping of SnO₂ nanosheets formed under hydrothermal conditions. Compositional analysis indicates that Ti(4+) ions are incorporated by substitution of Sn sites at a high level (16-18 at.%), with uniform distribution and no phase separation. Mössbauer spectroscopy quantified the relative content of Sn(II) and Sn(IV) in both Sn(II)-doped and Ti(IV)/Sn(II) co-doped SnO₂ samples. Electrochemical properties were investigated as an anode material in lithium ion batteries, demonstrating that Ti-doped SnO₂ nanosheets show improved cycle performance, which is attributed to the alleviation of inherent volume expansion of the SnO₂-based anode materials by substituting part of Sn sites with Ti dopants.

Anchoring ultra-fine TiO2–SnO2solid solution particles onto graphene by one-pot ball-milling for long-life lithium-ion batteries

“…Fig. [15][16][17][18][19][20]26,27 The coulombic efficiency of the TS@G electrode can be kept at ca. The discharge capacity reaches 1013 mA h g À1 for the rst cycle and stabilized at 670 mA h g À1 from the second cycle.…”

“…Numerous hybrid structures, such as Ti x Sn 1Àx O 3 solid solution, 15 (Sn-Ti)O 2 nanocomposites, 16 Ti 2/3 Sn 1/3 O 2 , 17 Ti(IV)/Sn(II) co-doped SnO 2 nanosheets, 18 tin titanate nanotubes, 19 mesoporous Sn-doped TiO 2 thin lms, 20 coaxial SnO 2 @TiO 2 nanotube hybrids 21 and TiO 2 -supported-SnO 2 22 were investigated for application in LIBs in recent years. Numerous hybrid structures, such as Ti x Sn 1Àx O 3 solid solution, 15 (Sn-Ti)O 2 nanocomposites, 16 Ti 2/3 Sn 1/3 O 2 , 17 Ti(IV)/Sn(II) co-doped SnO 2 nanosheets, 18 tin titanate nanotubes, 19 mesoporous Sn-doped TiO 2 thin lms, 20 coaxial SnO 2 @TiO 2 nanotube hybrids 21 and TiO 2 -supported-SnO 2 22 were investigated for application in LIBs in recent years.…”

Synthesis of Polyvinylpyrrolidone-Stabilized Nonstoichiometric SnO2 Nanosheets with Exposed {101} Facets and Sn(II) Self-Doping as Anode Materials for Li-Ion Batteries

“…As compared with the 3D Sn 2+ self-doped (8 at.%) and 1D Sn 2+ /Ti 4+ co-doped (12 at.%) SnO 2-δ hierarchical nanostructures in our previous report,[36] both yellow and black SnO 2-δ electrodes demonstrate much better cycle performance, which can be mainly attributed to the increased specific surface area from 21 and 26 to 82 m 2 /g. Moreover, the electrochemical performance is relatively better than that of ever-reported SnO 2 hierarchical nanostructures [21,24,25].…”

“…7acompares the initial two cycles of CV curves of the yellow and black SnO 2-δ electrodes, which show similar profiles. In the first cycle, both electrodes display two broad reduction peaks: one in the range of 0-0.25 V can be ascribed to the Li-Sn alloying process (Sn + xLi + + xe -→ 4 Li x Sn, 0 ≤ x ≤ 4.4),[36] while the another reduction peaks at around 1.0 V are different from the previous reports,[25,36] which may correspond to the formation of electrolyte interphase (SEI) and the reduction of SnO 2-δ into metallic Sn and Li 2 O [37]. This peak disappears in the subsequent cycles, indicating the reaction is irreversible.…”

Growth of Ultrafine SnO 2 Nanoparticles within Multiwall Carbon Nanotube Networks: Non-Solution Synthesis and Excellent Electrochemical Properties as Anodes for Lithium Ion Batteries

“…In the first discharge cycle, the reduction peak located at about 0.85 V corresponds the irreversible transformation of SnO 2 into metallic Sn (according to the equation: SnO 2 + 4Li + + 4e -→ 2Li 2 O + Sn), while the reduction peak at 0.12 V can be attributed to the formation of Li-Sn alloys. [27,29,[34][35][36] The broad peak at 0.57 V corresponds to the de-alloying of the Li-Sn alloys, whose current increases in the following scans, indicating a possible activation process in the electrode materials.…”