Lithium tetrafluoroborate

Names

IUPAC name

Other names

Borate(1-), tetrafluoro-, lithium

Identifiers

CAS Number

14283-07-9^Y

3D model (JSmol)

Interactive image

ChemSpider

3504162^Y

ECHA InfoCard

100.034.692

PubChem CID

4298216

UNII

AF751CNK2N^Y

CompTox Dashboard (EPA)

DTXSID00884741

InChI

InChI=1S/BF4.Li/c2-1(3,4)5;/q-1;+1^Y
Key: UFXJWFBILHTTET-UHFFFAOYSA-N^Y
InChI=1/BF4.Li/c2-1(3,4)5;/q-1;+1
Key: UFXJWFBILHTTET-UHFFFAOYAL

SMILES

[Li+].F[B-](F)(F)F

Properties

Chemical formula

LiBF₄

Molar mass

93.746 g/mol

Appearance

White/grey crystalline solid

Odor

odorless

Density

0.852 g/cm³ solid

Melting point

296.5 °C (565.7 °F; 569.6 K)

Boiling point

decomposes

Solubility in water

Very soluble^[1]

Hazards

Occupational safety and health (OHS/OSH):

Main hazards

Harmful, causes burns,
hygroscopic.

NFPA 704 (fire diamond)

Safety data sheet (SDS)

External MSDS

Related compounds

Other anions

Tetrafluoroborate,

Related compounds

Nitrosyl tetrafluoroborate

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is ^YN ?)

Infobox references

Chemical compound

Lithium tetrafluoroborate is an inorganic compound with the formula LiBF₄. It is a white crystalline powder. It has been extensively tested for use in commercial secondary batteries, an application that exploits its high solubility in nonpolar solvents.^[2]

Applications

Although BF₄⁻ has high ionic mobility, solutions of its Li⁺ salt are less conductive than other less associated salts.^[2] As an electrolyte in lithium-ion batteries, LiBF₄ offers some advantages relative to the more common LiPF₆. It exhibits greater thermal stability^[3] and moisture tolerance.^[4] For example, LiBF₄ can tolerate a moisture content up to 620 ppm at room temperature whereas LiPF₆ readily hydrolyzes into toxic POF₃ and HF gases, often destroying the battery's electrode materials. Disadvantages of the electrolyte include a relatively low conductivity and difficulties forming a stable solid electrolyte interface with graphite electrodes.

Thermal stability

Because LiBF₄ and other alkali-metal salts thermally decompose to evolve boron trifluoride, the salt is commonly used as a convenient source of the chemical at the laboratory scale:^[5]

LiBF₄ → LiF + BF₃

Production

LiBF₄ is a byproduct in the industrial synthesis of diborane:^[5]^[6]

8 BF₃ + 6 LiH → B₂H₆ + 6 LiBF₄

LiBF₄ can also be synthesized from LiF and BF₃ in an appropriate solvent that is resistant to fluorination by BF₃ (e.g. HF, BrF₃, or liquified SO₂):^[5]

LiF + BF₃ → LiBF₄

References

^ GFS-CHEMICALS Archived 2006-03-16 at the Wayback Machine
^ ^a ^b Xu, Kang. "Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries."Chemical Reviews 2004, volume 104, pp. 4303-418. doi:10.1021/cr030203g
^ S. Zhang; K. Xu; T. Jow (2003). "Low-temperature performance of Li-ion cells with a LiBF4-based electrolyte". Journal of Solid State Electrochemistry. 7 (3): 147–151. doi:10.1007/s10008-002-0300-9. S2CID 96775286. Retrieved 16 February 2014.
^ S. S. Zhang; z K. Xu & T. R. Jow (2002). "Study of LiBF4 as an Electrolyte Salt for a Li-Ion Battery". Journal of the Electrochemical Society. 149 (5): A586–A590. Bibcode:2002JElS..149A.586Z. doi:10.1149/1.1466857. Retrieved 16 February 2014.
^ ^a ^b ^c Robert Brotherton; Joseph Weber; Clarence Guibert & John Little (2000). "Boron Compounds". Ullmann's Encyclopedia of Industrial Chemistry. p. 10. doi:10.1002/14356007.a04_309. ISBN 3527306730.
^ Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry Vol. 1, 2nd Ed. New York: Academic Press. p. 773. ISBN 978-0121266011.