Titanium disulfide

A golden yellow solid with high electrical conductivity,[1] it belongs to a group of compounds called transition metal dichalcogenides, which consist of the stoichiometry ME2.

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.

Titanium disulfide nanotubes have a higher uptake and discharge capacity than the polycrystalline structure.

[5] The higher surface area of the nanotubes is postulated to provide more binding sites for the anode ions than the polycrystalline structure.

The properties of titanium disulfide powder have been studied by high pressure synchrotron x-ray diffraction (XRD) at room temperature.

The decrease in unit cell size was greater than was observed for MoS2 and WS2, indicating that titanium disulfide is softer and more compressible.

[6] It can be more easily synthesized from titanium tetrachloride, but this product is typically less pure than that obtained from the elements.

[11] This method affords amorphous material that crystallised at high temperatures to hexagonal TiS2, which crystallization orientations in the [001], [100], and [001] directions.

[11] More specialized morphologies—nanotubes, nanoclusters, whiskers, nanodisks, thin films, fullerenes—are prepared by combining the standard reagents, often TiCl4 in unusual ways.

[13] Owing to their spherical shape, these fullerenes exhibit reduced friction coefficient and wear, which may prove useful in various applications.

[14] Nucleation only occurs inside the micelle cage due to the insolubility of the charged species in the continuous medium, which is generally a low dielectric constant inert oil.

Quantum confinement creates well separated electronic states and increases the band gap more than 1 eV in comparison to the bulk material.

[16] The promise of titanium disulfide as a cathode material in rechargeable batteries was described in 1973 by M. Stanley Whittingham.

Titanium disulfide also has the fastest rate of lithium ion diffusion into the crystal lattice.

[18] In the 1990s, titanium disulfide was replaced by other cathode materials (manganese and cobalt oxides) in most rechargeable batteries.

For most solid-state batteries, high interfacial resistance lowers the reversibility of the intercalation process, shortening the life cycle.

Cartoon for intercalation of Li into TiS 2 cathode. The process involves swelling of one crystal axis and charge transfer from Li to Ti.
A battery is shown using titanium disulfide as a cathode. Lithium ions intercalate and deintercalate the layered titanium disulfide cathode as the battery is charged and discharged.
Hexagonal close packed structure of titanium disulfide where blue spheres represent titanium cations and clear spheres represent sulfide anions.