Lithium Pyrrolidinoborohydride SolutionCAS #: 144188-76-1

Synonyms

 Lithium trihydro-1-pyrrolidinylborate

Compound Formula: C4H11BLiN 

Molecular Weight: 90.89 

Appearance: Liquid 

Melting Point: N/A 

Boiling Point: N/A 

Density: 0.890 g/mL 

Solubility in H2O: N/A 

Exact Mass: 91.114459 

Monoisotopic Mass: 91.114459

Product Introduction: Potassium Bis(trifluoromethanesulfonyl)imide (KTFSI, CAS #: 144188-76-1)

Potassium bis(trifluoromethanesulfonyl)imide, with the chemical formula K[N(SO₂CF₃)₂] and CAS number 144188-76-1, is an advanced fluorinated salt that has gained prominence in next-generation energy storage and specialty chemical applications. Composed of potassium cations (K⁺) and bis(trifluoromethanesulfonyl)imide anions ([N(SO₂CF₃)₂]⁻), this white crystalline compound combines exceptional thermal stability, high ionic conductivity, and chemical inertness—properties that address key limitations of traditional potassium salts like potassium hexafluorophosphate (KPF₆). As demand grows for high-performance potassium-ion batteries (PIBs) and safe electrolyte systems, KTFSI has emerged as a critical material, offering a unique balance of performance, compatibility, and environmental resilience.

Chemical & Physical Properties

KTFSI’s molecular structure, characterized by two trifluoromethanesulfonyl groups bound to a central nitrogen atom, endows it with distinctive properties:

Solubility: Highly soluble in polar organic solvents such as ethylene carbonate (EC), dimethyl carbonate (DMC), and acetonitrile, forming electrolytes with concentrations up to 1.5 M. This solubility enables ionic conductivities of 12–16 mS/cm in optimized blends—surpassing KPF₆ in high-power applications. It is also sparingly soluble in non-polar solvents, providing versatility in reaction design.

Thermal Stability: Exhibits exceptional thermal stability, decomposing above 350°C—far higher than KPF₆ (decomposes >200°C) and many other potassium salts. This stability minimizes the risk of thermal runaway in batteries and high-temperature industrial processes.

Hygroscopicity: Low hygroscopicity compared to KPF₆, with minimal reaction with moisture even at 60% relative humidity. This simplifies manufacturing and storage, reducing the need for strict moisture control (moisture tolerance up to 300 ppm in electrolytes).

Density & Structure: Has a density of 2.3 g/cm³ and a molar mass of 381.3 g/mol, with a layered crystal structure that promotes efficient ion dissociation and transport in solution.

Electrochemical Window: Boasts a wide electrochemical stability window up to 5.0 V vs. K⁺/K, compatible with high-voltage PIB cathodes such as potassium manganese hexacyanoferrate and K₂Ni[Fe(CN)₆]—enabling batteries with energy densities exceeding 300 Wh/kg.

Key Applications

Potassium bis(trifluoromethanesulfonyl)imide (CAS 144188-76-1) is revolutionizing energy storage and specialty chemistry:

Potassium-Ion Batteries (PIBs): Serves as a premium electrolyte salt in PIBs, where its high conductivity and stability enhance cycle life and rate performance. In laboratory tests, KTFSI-based electrolytes enable PIBs with hard carbon anodes to achieve 4,000+ cycles with 85% capacity retention—nearly doubling the lifespan of KPF₆-based systems. Its ability to form a robust solid electrolyte interphase (SEI) layer, rich in potassium fluoride (KF) and organic fluorides, minimizes electrolyte decomposition and dendrite growth.

Ionic Liquid Synthesis: Acts as a precursor in the preparation of potassium-based ionic liquids, which are used as non-flammable electrolytes in high-temperature batteries and as green solvents in chemical synthesis. These ionic liquids exhibit low volatility and high thermal stability, making them suitable for industrial processes requiring temperature control up to 200°C.

Electrochemical Devices: Employed in supercapacitors and fuel cells to improve ion mobility and reduce internal resistance. In potassium-based supercapacitors, KTFSI electrolytes enhance power density by 30% compared to traditional aqueous electrolytes, supporting fast-charging applications.

Organic Synthesis: Functions as a Lewis acid catalyst in fluorination and sulfonylation reactions, facilitating the synthesis of pharmaceutical intermediates and agrochemicals with high selectivity (up to 98% yield). Its inert anion minimizes side reactions, making it ideal for sensitive chiral synthesis.

Material Science: Used in the preparation of conductive polymers and ionomers, where its ionic conductivity enhances the performance of fuel cell membranes and flexible electronics. When doped into polyaniline, it increases electrical conductivity to 50 S/cm, enabling use in wearable sensors.

Advantages & Limitations

KTFSI offers significant benefits over traditional potassium salts, with a few considerations:

Safety Profile: Superior thermal stability and low toxicity reduce fire and explosion risks in batteries, making it ideal for consumer electronics and grid storage. Its low HF generation upon hydrolysis (compared to KPF₆) minimizes corrosion of battery components and equipment.

Performance Metrics: Higher ionic conductivity and wider electrochemical window enable higher energy and power densities, addressing key bottlenecks in PIB commercialization. Its compatibility with silicon-based anodes (which offer higher capacity than hard carbon) further expands battery design possibilities.

Environmental Compatibility: Compared to perfluorinated compounds with long carbon chains, KTFSI exhibits lower bioaccumulation potential, aligning with regulatory trends toward safer fluorochemicals.

Limitations: Higher production costs than KPF₆ (approximately 4–5x) due to complex synthesis, limiting large-scale adoption in cost-sensitive applications. While less hygroscopic than KPF₆, it still requires dry handling to maintain purity in moisture-sensitive reactions.

Synthesis & Quality Control

KTFSI is produced via multi-step processes to ensure high purity:

Sulfonylation: Trifluoromethanesulfonyl fluoride (CF₃SO₂F) reacts with ammonia (NH₃) to form bis(trifluoromethanesulfonyl)amine (H[N(SO₂CF₃)₂]).

Potassiation: The amine is neutralized with potassium hydroxide (KOH) or potassium carbonate (K₂CO₃) in anhydrous solvent: H[N(SO₂CF₃)₂] + KOH → K[N(SO₂CF₃)₂] + H₂O.

Purification: Recrystallization from anhydrous acetonitrile or dimethylformamide (DMF) removes impurities, achieving battery-grade purity (>99.9%) with metal ion concentrations <1 ppm.

Quality control includes:

Ion chromatography to verify anion purity and detect residual sulfates or fluorides.

Inductively coupled plasma mass spectrometry (ICP-MS) to measure trace metals (Fe, Na, Ca <0.5 ppm).

Thermogravimetric analysis (TGA) to confirm thermal stability (>350°C decomposition onset).

Safety & Handling

Proper handling of KTFSI is guided by its chemical properties:

Toxicity: Low acute toxicity, but inhalation of dust or contact with moisture can release trace amounts of HF, causing mild irritation. Chronic exposure to fluoride ions may affect bone health, requiring adherence to occupational exposure limits (e.g., 2.5 mg/m³ for fluoride in the U.S.).

Handling: Use in well-ventilated fume hoods with moisture levels <10% RH. Wear PTFE gloves, splash goggles, and a dust respirator to prevent contact.

Storage: Keep in airtight, moisture-proof containers (e.g., stainless steel or HDPE) in a cool, dry area, separated from strong acids and reducing agents.

Disposal: Classified as hazardous waste due to fluoride content; dispose of in accordance with local regulations (e.g., EPA RCRA in the U.S.). Neutralize spills with calcium carbonate to form insoluble CaF₂.

Refer to the product’s Safety Data Sheet (SDS) for detailed emergency protocols.

Packaging & Availability

KTFSI is available in forms tailored to research and industrial needs:

Battery Grade: 1kg–25kg sealed aluminum drums with argon purging, suitable for electrolyte production.

Research Grade: 100g–5kg bottles in moisture-barrier packaging for laboratory use, with ultra-low metal impurities.

Solution Form: Pre-dissolved in organic solvent blends (e.g., 1.0 M in EC/DMC) in 1L–20L containers for immediate use in battery assembly.

Global production is led by manufacturers in China, Japan, and Europe, with annual capacity exceeding 300 tons and growing to meet PIB demand. High-purity grades (99.99%) are available for advanced electronics and catalysis applications.

For technical specifications, custom formulations, or supply chain insights, contact our team specializing in advanced electrolytes and fluorinated materials.

Health & Safety Information

 Signal Word: Danger 

Hazard Statements: H225-H319-H335 

Hazard Codes: F,Xi 

Risk Codes: 11-19-36/37 

Safety Statements: 16-26 

RTECS Number: N/A 

Transport Information: UN 3399 4.3/PG 1 

WGK Germany: 3

Chemical Identifiers

 Linear Formula: C4H11BLiN 

Pubchem CID: 23697345 

MDL Number: MFCD07784406 

EC No.: N/A 

IUPAC Name: lithium; pyrrolidin-1-ylboranuide 

SMILES: [Li+].[BH3-]N1CCCC1 

InchI Identifier: InChI=1S/C4H11BN.Li/c5-6-3-1-2-4-6;/h1-4H2,5H3;/q-1;+1 

InchI Key: CUBZYJJJUFGOBJ-UHFFFAOYSA-N

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 735 gallon liquid totes Special package is available on request.