Titanium disulfide
Names | |
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IUPAC name
Titanium(IV) sulfide
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Other names
Titanium Sulfide, titanium sulphide, titanium disulfide, titanium disulphide
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Identifiers | |
3D model (
JSmol ) |
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ECHA InfoCard
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100.031.699 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
TiS2 | |
Molar mass | 111.997 g/mol |
Appearance | yellow powder |
Density | 3.22 g/cm3, solid |
insoluble | |
Structure | |
hexagonal, space group P3m1, No. 164
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octahedral | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Titanium disulfide is an
Structure
With a
Intercalation
The single most useful and most studied property of TiS2 is its ability to undergo intercalation upon treatment with electropositive elements. The process is a
- TiS2 + Li → LiTiS2
LiTiS2 is generally described as Li+[TiS2−]. During the intercalation and deintercalation, a range of stoichimetries are produced with the general formul LixTiS2 (x < 1). During intercalation, the interlayer spacing expands (the lattice "swells") and the electrical conductivity of the material increases. Intercalation is facilitated because of the weakness of the interlayer forces as well as the susceptibility of the Ti(IV) centers toward reduction. Intercalation can be conducted by combining a suspension of the disulfide material and a solution of the alkali metal in anhydrous ammonia. Alternatively solid TiS2 reacts with the alkali metal upon heating.
The
Deintercalation is the opposite of intercalation; the cations diffuse out from between the layers. This process is associated with recharging a Li/TiS2 battery. Intercalation and deintercalation can be monitored by
Material properties
Formally containing the d0 ion Ti4+ and closed shell dianion S2−, TiS2 is essentially diamagnetic. Its magnetic susceptibility is 9 x 10−6 emu/mol, the value being sensitive to stoichiometry.
High pressure properties
The properties of titanium disulfide powder have been studied by high pressure
The unit cell of titanium disulfide is 3.407 by 5.695
Synthesis
Titanium disulfide is prepared by the reaction of the elements around 500 °C.[6]
- Ti + 2 S → TiS2
It can be more easily synthesized from titanium tetrachloride, but this product is typically less pure than that obtained from the elements.[6]
- TiCl4 + 2 H2S → TiS2 + 4 HCl
This route has been applied to the formation of TiS2 films by chemical vapor deposition. Thiols and organic disulfides can be employed in place of hydrogen sulfide.[9]
A variety of other titanium sulfides are known.[10]
Chemical properties of TiS2
Samples of TiS2 are unstable in air.[6] Upon heating, the solid undergoes oxidation to titanium dioxide:
- TiS2 + O2 → TiO2 + 2 S
TiS2 is also sensitive to water:
- TiS2 + 2H2O → TiO2 + 2 H2S
Upon heating, TiS2 releases sulfur, forming the titanium(III) derivative:
- 2 TiS2 → Ti2S3 + S
Sol-gel synthesis
Thin films of TiS2 have been prepared by the
Unusual morphologoes of TiS2
More specialized morphologies—
Fullerene-like materials
A form of TiS2 with a
Nanotubes
Nanotubes of TiS2 can be synthesized using a variation of the TiCl4/H2S route. According to transmission electron microscopy (TEM), these tubes have an outer diameter of 20 nm and an inner diameter of 10 nm.[14] The average length of the nanotubes was 2-5 µm and the nanotubes were proven to be hollow.[14] TiS2 nanotubes with open ended tips are reported to store up to 2.5 weight percent hydrogen at 25 °C and 4 MPa hydrogen gas pressure.[15] Absorption and desorption rates are fast, which is an attractive for hydrogen storage. The hydrogen atoms are postulated to bind to sulfur.[15]
Nanoclusters and nanodisks
Nanoclusters, or
Nanodisks of TiS2 arise by treating TiCl4 with sulfur in oleylamine.[16]
Applications
The promise of titanium disulfide as a
The use of TiS2 cathodes remains of interest for use in solid-state lithium batteries, e.g., for
In contrast to the all-solid state batteries, most lithium batteries employ liquid electrolytes, which pose safety issues due to their flammability. Many different solid electrolytes have been proposed to replace these hazardous liquid electrolytes. For most solid-state batteries, high interfacial resistance lowers the reversibility of the intercalation process, shortening the life cycle. These undesirable interfacial effects are less problematic for TiS2. One all-solid-state lithium battery exhibited a power density of 1000 W/kg over 50 cycles with a maximum power density of 1500 W/kg. Additionally, the average capacity of the battery decreased by less than 10% over 50 cycles. Although titanium disulfide has high electrical conductivity, high energy density, and high power, its discharge voltage is relatively low compared to other lithium batteries where the cathodes have higher reduction potentials.[18]
Notes
- ^ a b Smart, Lesley E.; Moore, Elaine A. (2005). Solid State Chemistry: An Introduction, Third Edition. Boca Raton, FL: Taylor & Francis.
- ^ a b Overton, Peter; Rourke, Tina; Weller, Jonathan; Armstrong, Mark; Atkins, Fraser (2010). Shriver and Atkins' Inorganic Chemistry 5th Edition. Oxford, England: Oxford University Press.
- ^ S2CID 22810398.
- .
- ^ PMID 15367984.
- ^ ISBN 978-0-471-30508-8.
- ^ .
- S2CID 97106786.
- .
- .
- ^ .
- .
- .
- ^ PMID 12744329.
- ^ PMID 12720434.
- PMID 18576280.
- S2CID 888879.
- ^ .
Further reading
- http://authors.library.caltech.edu/5456/1/hrst.mit.edu/hrs/materials/public/Titanium_disulfide.htm
- Tao, Y.; Wu, X.; Zhang, Y.; Dong, L.; Zhu, J.; Hu, Z. (2008). "Surface-assisted synthesis of microscale hexagonal plates and flower-like patterns of single-crystalline titanium disulfide and their field-emission properties". .
- Zhang, Y.; Li, Z.; Jia, H.; Luo, X.; Xu, J.; Zhang, X.; Yu, D.J. (2006). "TiS2 whisker growth by a simple chemical-vapor deposition method". Journal of Crystal Growth. 293 (1): 124–127. .