Lithium bis(trifluoromethane)sulfonimide

December 06, 2021
I鈥檓 a super-soluble lithium source.
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Lithium bis(trifluoromethane)sulfonimide (LiTFSI) is a hydrophilic organic salt that has many uses in electric and electronic systems. Its bis(trifluoromethane)sulfonimide anion, often referred to as bistriflimide, has the useful property of coordinating weakly with cations.

LiTFSI 鈥榮 other important property is its extremely high solubility in water: 21 molal or 鈮�6 kg/L of solution. Because of its solubility, it has been explored as an electrolyte for lithium-ion batteries, solar cells, and similar applications since at least the late 1980s. LiTFSI is a than the formerly used salt, lithium hexafluorophosphate (LiPF6).

In a 2021 Nature article, Andr茅 D. Taylor at New York University (New York City) and Yale University (New Haven, CT) and 18 colleagues there and at other institutions in the United States and the Republic of Korea reported a refinement in the use of LiTFSI in solar cells.

Photovoltaic cells made of inexpensive light-absorbing perovskites that have high power-conversion efficiencies have been developed over the past several years. To improve the cells鈥� ability to transport electrical charges, they are doped with a combination of LiTFSI and a semiconductor called Spiro-OMeTAD1; but this process is extremely slow.

Taylor and his fellow researchers solved the problem by into a solution of spiro-OMeTAD and LiTFSI while irradiating the mixture with ultraviolet light. They then cast a film made from the solution onto the perovskite light absorber. The process can be completed in 鈮�1 min, compared with the older, hours-long doping procedure.

The authors state, 鈥淭he CO2-treated interlayer exhibits approximately 100 times higher conductivity than a pristine [untreated] film while realizing stable, high-efficiency solar cells without any post-treatments.鈥� They also report that their method is useful for doping 蟺-conjugated polymers.

1. 2,2鈥�,7,7鈥�-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9-spirobifluorene, CAS Reg. No. 207739-72-8.

Lithium bis(trifluoromethane)sulfonimide聽
hazard information*

Hazard class**GHS code and hazard statement
Acute toxicity, oral, category 3H301鈥擳oxic if swallowed聽Chemical Safety Warning
Acute toxicity, dermal , category 3H311鈥擳oxic in contact with skinChemical Safety Warning
Skin corrosion/irritation, category 1BH314鈥擟auses severe skin burns and eye damageChemical Safety Warning
Serious eye damage/eye irritation, category 1H318鈥擟auses serious eye damageChemical Safety Warning
Specific target organ toxicity (nervous system), repeated exposure, oral, category 2H373鈥擬ay cause damage to nervous system through prolonged or repeated exposure if swallowedChemical Safety Warning
Short-term (acute) aquatic hazard, category 3H402聽鈥擧armful to aquatic life
Long-term (chronic) aquatic hazard, category 3H412鈥擧armful to aquatic life with long-lasting effects

*Compilation of selected safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.聽

Lithium bis (trifluoromethane) sulfonimide聽fast facts

CAS Reg. No.90076-65-6

nomenclature
Methanesulfonamide, 1,1,1-trifluoro-N-[(trifluoromethyl)
sulfonyl]-, lithium salt (1:1)
Empirical formulaC2F6LiNO4S2
Molar mass287.09 g/mol
AppearanceHygroscopic white powder
Melting point234鈥�238 掳C
Water solubility鈮�6 kg/L
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