Lithium-ion battery electrolyte additives · film formers (VC, FEC, PS, DTD), LiPO2F2, flame-retardant and overcharge additives · dosage in wt%, purity, moisture ppm, acidity as HF, APHA colour, chlorine
Electrolyte additives are small additions to a lithium-ion electrolyte, measured in weight percent of the finished electrolyte, that build a protective film on the electrodes (the solid-electrolyte interphase, SEI, on the anode and the cathode-electrolyte interphase, CEI), or add flame retardance, overcharge protection or acid and water scavenging. Ask three things first: which additives and at what wt.% for your cell chemistry; the purity, moisture and acidity limits for each lot; and how each is packed and stabilised.
Functional additives for liquid lithium-ion electrolytes, supplied as single compounds or as a blend: film formers such as VC, FEC, PS and DTD, lithium salts such as lithium difluorophosphate (LiPO2F2), flame-retardant phosphates such as triphenyl phosphate, and overcharge redox-shuttle compounds. Base solvents (EC, DMC, EMC, DEC), conducting salt LiPF6 as the main salt, finished electrolytes, solid electrolytes and sodium-ion electrolytes are outside this page except where compared.
CNFX editorial research · Sources checked October 11, 2026 · 4 sources
A 2025 open-access review in Small groups electrolyte additives by action: film formation, overcharge and over-discharge protection, high-voltage and wide-temperature operation, acid and water scavenging, limiting gas evolution, flame retardance and inhibiting aluminium corrosion. It reports that about 1 wt.% of vinylene carbonate (VC), triphenyl phosphate (TPP) or ethylene sulfate (DTD), or 10 wt.% of fluoroethylene carbonate (FEC), added to an EC:DEC electrolyte developed a stable SEI on a graphite anode. Sultone additives at about 0.1–4 wt.% mitigated propylene carbonate co-intercalation in graphite, and a graphite ǀǀ LiCoO2 cell with 0.1 wt.% 1,3-propane sultone (PS) cycled for over 50 cycles with 82% capacity retention. [1]
The same review describes lithium difluorophosphate (LiPO2F2) as a well-known additive to reduce cell impedance and improve capacity and cycle life; Cu ǀǀ Li cells with 2 wt.% each of LiDFP and VC reached 95% coulombic efficiency after 80 cycles. For high-voltage cathodes, graphite ǀǀ LiNi0.5Mn1.5O4 cells with succinic anhydride (2 wt.%) plus PS (3 wt.%) outperformed either additive alone, while graphite ǀǀ NMC442 cells with 2 wt.% succinonitrile and 2 wt.% VC suffered severe capacity loss and gas generation at about 4.5 V. FEC at about 2 wt.% improved graphite capacity from –40 to 20 °C. [1]
For fire safety, the review states that phosphorus- and fluorine-based compounds interrupt combustion by scavenging H· and OH· radicals; electrolytes with about 10 to 15% TPP showed self-extinguishing behaviour, and combinations of 10% TPP with 5% FEC (MCMB ǀǀ Li) or 2% FEC (NMC ǀǀ Li) performed well. It warns that raising additive concentration raises viscosity, which may cause high impedance and poor capacity retention. Overcharge additives include redox-shuttle compounds such as substituted N-ethylphenothiazines. [1]
Editorial calculation: in a 100 kg electrolyte batch, 1 wt.% VC is 1 kg, 2 wt.% FEC is 2 kg and 0.5 wt.% PS is 0.5 kg; a blend delivered as one package must state the ratio of each component so the dosing rate gives the intended wt.% of each.
Toxicity can decide between sulphur film formers. Muschiol and colleagues at the University of Münster, its MEET Battery Research Center and Forschungszentrum Jülich's Helmholtz-Institute Münster (Archives of Toxicology, 2026) tested LP57 electrolyte (EC/EMC 3 + 7 by volume with 1 M LiPF6) without additive and with 2 wt% of 1,3-propane sultone (PS), prop-1-ene-1,3-sultone (PES) or ethylene sulfate (DTD), pristine and after 2 and 200 charge–discharge cycles. Their Table 1 lists PS (122.14 g/mol) as IARC category 2A (probably carcinogenic to humans) and with category 1B (presumed human carcinogen) and category A (genotoxic carcinogen without threshold) classifications under SCOEL and the EU CLP Regulation, while PES (120.13 g/mol) and DTD (124.12 g/mol) are not listed. In their assays the additive-free electrolyte was not genotoxic at any ageing stage; electrolytes with PS and PES raised micronucleus frequency in HepG2 cells while DTD did not; mutagenicity in Salmonella ranked PS > PES > DTD; and the mutagenicity of the PS electrolyte did not fall with ageing, unlike PES and DTD. The authors conclude that DTD should be preferred over PS and PES from a toxicological point of view. [4]
Editorial note: the 2 wt% dose tested sits inside the 0.1–4 wt.% range the review reports for sultone additives. If a blend contains PS, ask the supplier for its hazard classification and safety data sheet, and whether a DTD-based alternative meets your cell's performance targets. [4][1]
Give the supplier the cell chemistry (anode, cathode, cut-off voltage), base electrolyte (salt, solvents and ratio), each additive and its target wt.% in the finished electrolyte, whether you want single compounds or a pre-mixed blend, the purity, moisture, acidity (as HF), colour, chlorine and metal-ion limits, stabiliser content, packaging and inert-gas blanketing, storage temperature, the certificate of analysis per lot, and quantity.
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Set purity, moisture, acidity and colour limits per lot
Water matters because LiPF6 reacts with it: the review gives the reaction H2O + LiPF6 → POF3 + LiF + 2 HF and notes that the HF generated could corrode or damage the SEI film. [1] PCC's data sheet for vinylene carbonate (CAS 872-36-6), sold as a membrane-forming additive for Li-ion electrolytes, lists purity (GC) min. 99.99%, moisture ≤30 ppm, colour (APHA) ≤20, BHT 70-110 ppm and total chlorine ≤15 ppm, with density 1.36 g/cm3 at 20 °C, melting point 15 °C, boiling point 168 °C and flash point 80 °C. [2] US patent 7,268,238 on 4-fluoroethylene carbonate manufacture states that FEC for lithium secondary battery electrolyte is regulated to purity 99.8 wt % or more, moisture 20 ppm or less, APHA colour 50 or less, metal ion content 1 ppm or less and acidity (based on HF) 50 ppm or less; its example product contained 99.89 wt % FEC and 0.003 wt % HF. [3]
Editorial calculation: an additive dosed at 2 wt.% carries 2% of its own moisture into the electrolyte, so VC at the 30 ppm limit adds at most 30 × 0.02 = 0.6 ppm water, and FEC at 10 wt.% with 20 ppm moisture adds at most 20 × 0.10 = 2 ppm. [2][3]
Editorial note: VC melts at 15 °C per the PCC sheet, so a drum stored below that temperature may arrive solid; agree the storage and thawing procedure with the supplier. [2]
03
Electrolyte and additive maker listed for this page
Capchem lists lithium-ion electrolytes together with the lithium salts, solvents and additives used in them; ask for its VC and FEC lot specifications against the limits in the purity section above.
When requesting quotations, ask each supplier which additives it makes itself, the specification and test method for each, whether it blends to a customer ratio, the stabiliser used, packaging under inert gas, and a recent certificate of analysis.
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VC, FEC, sultones, DTD, LiPO2F2, TPP and redox shuttles by role and dose
Four of the seven additives below are film formers; in the review, about 1 wt.% VC or DTD, or 10 wt.% FEC, in an EC:DEC electrolyte formed a stable SEI on graphite. [1]
Dose, moisture, purity, HF acidity and APHA colour per additive lot
Lot limits here come from one VC data sheet and one FEC patent: moisture ≤30 ppm for VC and ≤20 ppm for FEC, purity of 99.99% (GC) for VC and 99.8 wt% for FEC. [2][3]
1 company lists this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Shenzhen Capchem Technology Co., Ltd.
Manufacturing site to be confirmed for the order
Its website lists lithium-ion battery electrolytes and the lithium salts, solvents and additives used in them.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
How much VC or FEC goes into a lithium-ion electrolyte?
A 2025 review reports a stable graphite SEI with about 1 wt.% VC or 10 wt.% FEC in EC:DEC; other cited cells used 0.5–5 wt.% FEC. [1]
What moisture and acidity limits apply to FEC?
A FEC manufacturing patent cites purity ≥99.8 wt%, moisture ≤20 ppm, APHA ≤50, metal ions ≤1 ppm and acidity as HF ≤50 ppm. [3]
Why does water matter in electrolyte additives?
Water reacts with LiPF6 to form HF, which the review says could corrode or damage the SEI film. [1]
Is 1,3-propane sultone more hazardous than DTD as an additive?
A 2026 University of Münster study found electrolytes with 2 wt% PS genotoxic and mutagenic in vitro while DTD was not genotoxic, and concluded DTD should be preferred over PS and PES toxicologically; PS is IARC category 2A. [4]
Sources and what still needs a direct check
Sources checked 2026-10-11. The sources are an open-access review on functional electrolyte additives, a producer's vinylene carbonate data sheet, a US patent on fluoroethylene carbonate manufacture, and a 2026 University of Münster toxicology study of sulphur-containing additives.
