SEI-forming additive: Purity ≥99.5%, Density 1.2-1.5 g/cm³

Component Specifications

Definition

SEI-forming additive is a specialized chemical compound incorporated into lithium-ion battery electrolytes to facilitate the controlled formation of a stable solid-electrolyte interphase (SEI) layer on graphite or silicon-based anode surfaces during initial battery cycling. This additive decomposes preferentially at the anode-electrolyte interface, creating a protective film that prevents further electrolyte decomposition while allowing lithium-ion transport.

Working Principle

The additive molecules undergo electrochemical reduction at the anode surface during initial charging cycles, forming a stable, ion-conductive but electron-insulating layer that passivates the anode. This prevents continuous electrolyte decomposition, reduces irreversible capacity loss, and enhances battery safety and longevity.

Materials

Organic compounds including vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfite (ES), lithium difluoro(oxalato)borate (LiDFOB), and proprietary organosilicon or organophosphorus compounds.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Purity	≥99.5%
Density	1.2-1.5 g/cm³
Moisture Content	≤20 ppm
Decomposition Voltage	0.8-1.2 V vs. Li/Li⁺
Recommended Concentration	0.5-5.0 wt% in electrolyte

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 12405-4, IEC 62660-2, UL 1642, GB/T 18287

Parent Products

This component is used in the following industrial products

Lithium-Ion Battery Electrolyte Additive Package

Chemical additive blend for enhancing lithium-ion battery electrolyte performance and safety.

View Product Details

Engineering Analysis

Risks & Mitigation

Electrolyte decomposition if additive concentration is incorrect
Gas generation during formation
Reduced ionic conductivity if SEI layer is too thick
Compatibility issues with specific cathode materials

FMEA Triads

Trigger: Insufficient additive concentration
Failure: Unstable SEI formation leading to continuous electrolyte decomposition
Mitigation: Optimize concentration through electrochemical testing and implement precise dosing systems

Trigger: Moisture contamination in additive
Failure: Hydrogen fluoride generation and battery performance degradation
Mitigation: Maintain moisture levels below 20 ppm through dry room handling and sealed packaging

Trigger: Incompatibility with specific electrolyte solvents
Failure: Poor SEI formation or excessive gas generation
Mitigation: Conduct compatibility testing with full electrolyte formulation before implementation

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.1% concentration in final electrolyte formulation

Test Method

Electrochemical impedance spectroscopy (EIS), cyclic voltammetry, gas chromatography-mass spectrometry (GC-MS) for decomposition analysis

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of SEI-forming additive

Manufacturer profiles associated with SEI-forming additive.

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Frequently Asked Questions

What is the primary function of SEI-forming additives?

To create a stable protective layer on anode surfaces that prevents continuous electrolyte decomposition while allowing lithium-ion transport.

Which materials are commonly used as SEI-forming additives?

Vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethylene sulfite (ES), and various borate-based compounds are most common.

How do SEI-forming additives affect battery performance?

They improve cycle life, reduce irreversible capacity loss, enhance thermal stability, and prevent gas generation during operation.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

SEI-forming additive