Lithium titanate

Lithium titanates are chemical compounds of lithium, titanium and oxygen. They are mixed oxides and belong to the titanates. The most important lithium titanates are:
* lithium titanate spinel, Li₄Ti₅O₁₂ and the related compounds up to Li₇Ti₅O₁₂. These titanates are used in lithium-titanate batteries.
* lithium metatitanate, a compound with the chemical formula Li₂TiO₃ and a melting point of It is a white powder with possible applications in tritium breeding materials in nuclear fusion applications.
Other lithium titanates, i.e. mixed oxides of the system Li₂O–TiO₂, are:
* Lithium orthotitanate Li₄TiO₄, melting point of
* Ramsdellite lithium titanate Li₂Ti₃O₇ and Li_''x''TiO₂ (0 ≦ ''x'' ≦ 0.57) with ramsdellite structure.

Lithium metatitanate

Lithium metatitanate is a compound with the chemical formula Li₂TiO₃. It is a white powder with a melting point of . It is also used as an additive in porcelain enamels and ceramic insulating bodies based on titanates. It is frequently utilized as a flux due to its good stability. In recent years, along with other lithium ceramics, metatitanate pebbles have been the subject of research efforts towards tritium breeding materials in nuclear fusion applications.

Crystallization

The most stable lithium titanate phase is β-Li₂TiO₃ that belongs to the monoclinic system. A high-temperature cubic phase exhibiting solid-solution type behavior is referred to as γ-Li₂TiO₃ and is known to form reversibly above temperatures in the range 1150-1250 °C. A metastable cubic phase, isostructural with γ-Li₂TiO₃ is referred to as α-Li₂TiO₃; it is formed at low temperatures, and transforms to the more stable β-phase upon heating to 400 °C.

Uses in sintering

The sintering process is taking a powder, putting it into a mold and heating it to below its melting point. Sintering is based on atomic diffusion, the atoms in the powder particle diffuse into surrounding particles eventually forming a solid or porous material.

It has been discovered that Li₂TiO₃ powders have a high purity and good sintering ability.

Uses as a cathode

Molten carbonate fuel cells

Lithium titanate is used as a cathode in layer one of a double layer cathode for molten carbonate fuel cells. These fuel cells have two material layers, layer 1 and layer 2, which allow for the production of high power molten carbonate fuel cells that work more efficiently.Prohaska, Armin et al. (1997) "Double layer cathode for molten carbonate fuel cells and method for producing the same"

Lithium-ion batteries

Li₂TiO₃ is used in the cathode of some lithium-ion batteries, along with an aqueous binder and a conducting agent. Li₂TiO₃ is used because it is capable of stabilizing the high capacity cathode conducting agents; LiMO₂ (M=Fe, Mn, Cr, Ni). Li₂TiO₃ and the conduction agents (LiMO₂) are layered in order to create the cathode material. These layers allow for the occurrence of lithium diffusion.

Lithium-titanate battery

The lithium-titanate battery is a rechargeable battery that is much faster to charge than other lithium-ion batteries. It differs from other lithium-ion batteries because it uses lithium-titanate on the anode surface rather than carbon. This is advantageous because it does not create a solid electrolyte interface layer, which acts as a barrier to the ingress and egress of Li-ion to and from the anode. This allows lithium-titanate batteries to be recharged more quickly and provide higher currents when necessary. A disadvantage of the lithium-titanate battery is a much lower capacity and voltage than the conventional lithium-ion battery. The lithium-titanate battery is currently being used in battery electric vehicles and other specialist applications.

Tritium breeding

Fusion reactions, such as those in the proposed ITER thermonuclear demonstrator reactor, are fueled by tritium and deuterium. Tritium resources are extremely limited in their availability, with total resources currently estimated at twenty kilograms. Lithium-containing ceramic pebbles can be used as solid breeder materials in a component known as a helium-cooled breeder blanket for the production of tritium. The breeding blanket constitutes a key component of the ITER reactor design. In such reactor designs tritium is produced by neutrons leaving the plasma and interacting with lithium in the blanket. Li₂TiO₃ along with Li₄SiO₄ are attractive as tritium breeding materials because they exhibit high tritium release, low activation, and chemical stability.

Synthesis of lithium-titanate breeder powder

Li₂TiO₃ powder is most commonly prepared by the mixing of lithium carbonate, Ti-nitrate solution, and citric acid followed by calcination, compaction, and sintering. The nanocrystalline material created is used as a breeder powder due to its high purity and activity.A. Shrivastava, T. Kumar, R. Shukla, P. Chaudhuri, Li2TiO3 pebble fabrication by freeze granulation & freeze drying method, Fusion Eng. Des. 168 (2021) 112411. https://doi.org/10.1016/j.fusengdes.2021.112411.

See also

* Lithium battery

References

{{Titanates

Titanates
Lithium salts