Lithium tert-butylcyclopentadienideCAS #: 50356-03-1

Synonyms

 Tert-butylcyclopentadienide lithium, Lithium tetramethylcyclopentadienide, 2,3,4,5-Tetramethyl-2,4-cyclopentadienyllithium, t-butylcyclopentadienyl lithium

Compound Formula: C9H13Li 

Molecular Weight: 128.14 

Appearance: White to off-white powder 

Melting Point: 273-277 °C 

Boiling Point: N/A 

Density: N/A 

Solubility in H2O: Reacts violently 

Exact Mass: 128.117729 g/mol 

Monoisotopic Mass: 128.117729 g/mol 

Sensitivity: Moisture and air sensitive

Product Introduction: Lithium Oxalyldifluoroborate (LiODFB, CAS #: 50356-03-1)

Lithium oxalyldifluoroborate, with the chemical formula LiC₂O₄BF₂ and CAS number 50356-03-1, is a specialized lithium salt recognized for its exceptional performance as an electrolyte additive and co-salt in lithium-ion batteries (LIBs). This white crystalline compound, structurally related to LiDFOB, combines oxalate and fluoroborate moieties to deliver superior thermal stability, efficient solid electrolyte interphase (SEI) formation, and compatibility with a wide range of electrode materials. Its unique properties make it a valuable material for enhancing battery safety, cycle life, and high-temperature durability, particularly in advanced energy storage systems.

Chemical & Physical Properties

LiODFB exhibits key properties that distinguish it as a high-performance electrolyte component:

Solubility: Highly soluble in common organic carbonate solvents, including ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), enabling flexible electrolyte formulations with concentrations up to 0.8 M.

Ionic Conductivity: Delivers moderate ionic conductivity (typically 5–8 mS/cm in optimized solvent blends), supporting efficient lithium-ion transport while maintaining SEI-stabilizing properties.

Thermal Stability: Maintains stability up to approximately 230°C, outperforming conventional LiPF₆ and providing robust performance in high-temperature battery operations.

Electrochemical Window: Boasts a wide electrochemical stability window (up to 4.9 V vs. Li⁺/Li), compatible with high-voltage cathodes such as LiNi₀.₈Co₀.₁Mn₀.₁O₂ (NCM811) and LiCoO₂.

Hydrolytic Stability: Exhibits better resistance to moisture-induced hydrolysis than LiPF₆, reducing the formation of corrosive hydrofluoric acid (HF) and protecting electrode materials from degradation.

Key Applications in Lithium-Ion Batteries

Lithium oxalyldifluoroborate (CAS 50356-03-1) plays a critical role in advancing battery technology through targeted applications:

SEI-Forming Additive: Used in low concentrations (0.5–2% by weight) to promote the formation of a dense, stable SEI layer on graphite anodes. The oxalate groups facilitate uniform passivation, reducing irreversible capacity loss and extending cycle life by 15–25% in long-term cycling tests.

High-Temperature Electrolytes: Blended with LiPF₆ or LiFSI in electrolytes for batteries operating at 40–70°C (e.g., electric vehicle batteries and industrial energy storage), where its thermal stability minimizes electrolyte decomposition and gas generation.

Silicon and Alloy Anodes: Enhances the compatibility of electrolytes with high-capacity silicon or silicon-carbon anodes by forming a flexible SEI that accommodates the large volume changes (up to 300%) during lithiation/delithiation, a key challenge in next-generation anode development.

Safety Enhancement: Reduces the flammability of electrolytes and suppresses thermal runaway in LIBs, making it suitable for consumer electronics and automotive applications where safety is paramount.

Advantages Over Conventional Electrolyte Salts

LiODFB offers distinct benefits compared to traditional lithium salts and additives:

SEI Superiority: Forms a more robust and flexible SEI than additives like fluoroethylene carbonate (FEC), particularly on high-capacity anodes, due to the synergistic interaction of oxalate and fluoroborate groups.

Stability Balance: Combines the thermal resilience of borate-based salts with the passivating properties of oxalate, providing better stability than LiPF₆ without the cathode corrosion risks associated with some imide salts (e.g., LiTFSI).

Cathode Compatibility: Works seamlessly with layered oxides (NCM, NCA), spinels (LMO), and phosphates (LFP), avoiding the metal dissolution issues observed with certain fluorinated salts.

Cost-Effectiveness: More affordable than advanced imide salts (e.g., LiFSI) while delivering comparable performance enhancements, making it a viable option for large-scale battery production.

Synthesis & Quality Control

LiODFB is synthesized through controlled processes to ensure high purity and consistency:

Precursor Reaction: Lithium oxalate (Li₂C₂O₄) reacts with boron trifluoride (BF₃) in an anhydrous organic solvent (e.g., tetrahydrofuran) under inert atmosphere, yielding LiODFB and byproducts.

Purification: The crude product is purified via recrystallization from anhydrous solvents (e.g., acetonitrile) and dried under vacuum to remove residual moisture and impurities.

Quality control includes ion chromatography (IC) for anion analysis, inductively coupled plasma mass spectrometry (ICP-MS) for trace metal detection (ensuring <10 ppm impurities), and Karl Fischer titration to verify moisture content (<10 ppm). Battery-grade LiODFB typically achieves purity levels of 99.9% or higher.

Safety & Handling

Proper handling of LiODFB is essential to maintain performance and safety:

Hygroscopicity: Moderately hygroscopic; store in sealed containers under inert atmosphere (nitrogen or argon) to prevent hydrolysis and maintain solubility.

Toxicity: May cause skin and eye irritation; use chemical-resistant gloves, goggles, and a lab coat when handling. Avoid inhalation of dust or contact with mucous membranes.

Reactivity: Incompatible with strong acids (which release HF) and reducing agents. Keep away from open flames, as it may increase the flammability of combustible materials.

Storage: Store in a cool, dry, well-ventilated area, separate from oxidizing agents and organic solvents.

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

Packaging & Availability

LiODFB is available in forms tailored to battery research and manufacturing needs:

Anhydrous Powder: Packaged in moisture-proof aluminum bags (100g–5kg) with inert gas purging, ideal for laboratory and pilot-scale electrolyte formulation.

Bulk Quantities: Available in 25kg–50kg drums for industrial production, with strict moisture control during packaging to ensure stability.

Custom purities and particle sizes are available upon request for specialized applications. Our battery-grade LiODFB meets the stringent quality requirements of automotive and electronics industries, ensuring consistent performance in large-scale battery production.

For technical specifications, pricing, or sample requests, contact our sales team specializing in advanced electrolyte materials for energy storage.

Health & Safety Information

 Signal Word: Danger 

Hazard Statements: H228-H261-H314 

Hazard Codes: F, C Precautionary 

Statements: P210-P231+P232-P280-P305+P351+P338-P310-P422 

Flash Point: 17 °C 

Risk Codes: N/A 

Safety Statements: N/A 

Transport Information: UN 3396 4.1(4.3) / PG II 

WGK Germany: 3 

GHS Pictogram: Image,Image

Chemical Identifiers 

Linear Formula: C9H13Li 

Pubchem CID: 12713396 

MDL Number: MFCD02093630 

EC No.: 684-543-4 

IUPAC Name: lithium; 5-tert-butylcyclopenta-1,3-diene 

SMILES: [Li+].CC(C)(C)[C-]1C=CC=C1 

InchI Identifier: InChI=1S/C9H13.Li/c1-9(2,3)8-6-4-5-7-8;/h4-7H,1-3H3;/q-1;+1 InchI Key: JPXWDGHNZTWBHY-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.