Lithium Hexafluorophosphate (LiPF₆)

Lithium Hexafluorophosphate Overview

 

Lithium hexafluorophosphate (abbreviated as LiPF₆), molecular formula LiPF₆, CAS No. 21324-40-3, is the core lithium salt material for lithium-ion battery electrolytes, commonly referred to as "lithium salt" in the industry. At room temperature, it appears as a white crystalline powder with strong deliquescence and is extremely prone to hydrolysis upon exposure to moisture. It dissolves readily in organic solvents such as carbonates, methanol and ethanol. Within electrolyte systems, it delivers excellent ionic conductivity and electrochemical window performance and can form a stable SEI film on the anode surface.

 

 

LiPF₆ is the dominant lithium-salt grade for power batteries, consumer lithium-ion batteries and energy-storage batteries, and has long held the leading position among electrolyte lithium salts. Balanced in overall cost, supply-chain maturity and performance, it outperforms new-generation lithium salts at present. It is often compounded with lithium bis(fluorosulfonyl)imide (LiFSI) to achieve both improved cycle life and low-temperature performance.

Two main industrialized routes are adopted: hydrogen-fluoride solvent method and organic-solvent method. Lab-scale routes such as gas-solid method are rarely used for mass production due to scaling difficulties.

Hydrogen-Fluoride Solvent Method (Mainstream Industrial Route)
Using lithium fluoride, anhydrous hydrogen fluoride (HF) and phosphorus pentafluoride (PF₅) as raw materials, synthesis, crystallization and filtration are carried out at low temperature within an anhydrous hydrogen-fluoride system, followed by drying under inert gas and hermetic packaging. This yields high-purity products with low impurities, suitable for power-battery-grade applications. However, it imposes extremely high anti-corrosion requirements for equipment and requires strict HF control, alongside high energy consumption. Leading Chinese enterprises adopt continuous-process technology with continuous gas generation, synthesis and crystallization, delivering stable batch quality and well-controlled side reactions.

Organic-Solvent Method
Reactions take place in organic-solvent systems such as carbonates. It avoids large volumes of anhydrous HF and has relatively lower equipment barriers. Nevertheless, controlling solvent residues poses challenges, and its high-purity power-grade stability is inferior to that of the hydrogen-fluoride route. It is mostly applied in consumer batteries and mid-to-low-grade electrolytes.

The complete production line is equipped with supporting units for deep water removal, metal-ion removal and inert-atmosphere refining. Leading Chinese manufacturers leverage integrated layouts covering fluorochemical and lithium resources, with self-supported hydrogen-fluoride and PF₅ facilities, granting prominent cost- and quality-related advantages.

Key differences among grades lie in the precision of control over moisture, free HF and metallic ions. Power-battery-grade and energy-storage-grade products impose stringent requirements for low moisture and low metallic-ion content. Consumer-electronic-grade material must not be downgraded and substituted for power-battery or energy-storage systems.

Upstream Raw Materials

Core raw materials include lithium fluoride / lithium carbonate, anhydrous hydrogen fluoride and phosphorus pentafluoride. Fluorine resources originate from fluorite. Auxiliary materials comprise carbonate solvents as well as inert protective gases such as argon and nitrogen. Industrial barriers centre on high-purity anhydrous HF, fluorine-resistant corrosion-proof equipment and lithium-resource supply.

Downstream Applications

Core lithium salt for electrolytes: performs lithium-ion conduction, accounting for roughly 40%–50% of electrolyte costs; determines electrolyte ionic conductivity, electrochemical stability and battery cycle-safety performance.

New-energy vehicles: electrolytes for power ternary batteries and lithium-iron-phosphate batteries.

Energy-storage sector: large-scale energy-storage power stations, residential energy-storage systems, portable energy-storage power supplies.

3C consumer lithium-ion batteries: mobile phones, tablets, laptops, Bluetooth earphones, power banks.

Others: special electrochemical devices and electrochemical scientific research.

Industrial chain: Lithium hexafluorophosphate manufacturers → electrolyte producers → lithium-ion-cell manufacturers → end-user vehicle enterprises, energy-storage integrators and consumer-electronic brands.

LiPF₆ hydrolyses upon contact with water or moisture to produce highly corrosive substances such as hydrogen fluoride (HF). It poses skin-corrosion hazards, serious eye damage and inhalation risks, and may cause chronic harm to bones and teeth. It shall be managed strictly as a corrosive hazardous chemical.

Packaging: Stainless-steel-lined aluminium or steel cylinders filled with argon for hermetic sealing to isolate moisture; common net weights: 10 kg, 25 kg. Ordinary plastic drums or open packaging are prohibited.

Storage: Store in cool, dry, air-tight warehouses under inert-atmosphere protection with temperature control. Strictly isolate from air and moisture. Warehouses shall be moisture-proof and well-ventilated. Store separately, away from oxidants, water sources, acids and alkalis. Once opened, feed materials rapidly to avoid prolonged exposure and moisture absorption.

Transportation: Regulated as corrosive hazardous chemical. Protect from moisture and rain; avoid direct sunlight and high temperatures. Prevent packaging damage and water ingress throughout transit. Transport vehicles shall be equipped with emergency-protection and decontamination supplies.

Operational Protection: Wear fluorine-resistant face shields, HF-resistant gloves and protective clothing. Operate inside anhydrous glove boxes or closed negative-pressure feeding systems. In case of skin contact, apply calcium gluconate gel for emergency treatment and seek medical attention immediately.

Waste Disposal: Spent material is classified as hazardous waste. Qualified hazardous-waste-treatment institutions shall neutralize HF and fluorides. Dumping or direct water-washing discharge is forbidden.

Q: Why must moisture content of lithium hexafluorophosphate be strictly controlled?

A: LiPF₆ undergoes rapid hydrolysis in the presence of water, generating corrosive substances including hydrogen fluoride (HF). HF corrodes battery cells and catalyses electrolyte decomposition, resulting in battery swelling due to gas generation, sharp cycle-performance degradation and thermal-runaway risks. Moisture is therefore one of the most critical control indicators for electrolyte systems.

Q: What are the differences between LiPF₆ and LiFSI? How to select between them?

A: LiPF₆ features mature industrialization, lower cost and balanced comprehensive performance, serving as the prevailing base lithium salt. LiFSI delivers better high-voltage resistance and hydrolysis stability, yet it comes with higher costs and risks of aluminium-foil corrosion. The industry generally adopts LiPF₆ as the main component with a small proportion of LiFSI added in compound formulations to balance cycle life and high-/low-temperature performance. For high-precision power-battery and energy-storage systems, power-battery-grade LiPF₆ shall be selected; consumer-electronic-grade material must not be used as a downgraded substitute.

Q: What are the industrial advantages of China's lithium-hexafluorophosphate sector?

A: China is the world's largest producer and supplier of lithium hexafluorophosphate with prominent industrial strengths. Supported by complete fluorine-lithium supply chains covering fluorite and lithium ore as well as anhydrous HF, integrated large-scale manufacturers achieve cost-effective production and stable deliveries. Mature continuous-synthesis technology enables domestic substitution for high-purity power-battery-grade products, whose purity and metallic-ion indicators match international benchmarks. Proximity to electrolyte and cell industrial clusters shortens logistics cycles and enables rapid order response. Mature fluorochemical-process equipment and three-waste-treatment systems support stable large-volume long-term supply contracts. Leveraging China's huge LiPF₆-market advantages, 7DCHEM applies dual-warehouse services in Poland to meet chemical-procurement demands across Central-Eastern Europe and Ukraine.

Parameters, process and industrial data in this document are compiled from publicly-available authoritative sources for reference only:

ChemicalBook / PubChem physical-property database (CAS 21324-40-3) - molecular formula, molecular weight, density, thermal stability and other physicochemical indicators

Merck / Sigma-Aldrich lithium-hexafluorophosphate technical datasheets and SDS - hazard classification and hydrolysis characteristics

China Lithium-Battery-Material Industry Research Report (2025–2026 China LiPF₆ Market Analysis) - process routes, production capacity and downstream-market structure

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