What to know before you buy
Electrolyte additives are small amounts of compounds added to a battery electrolyte to shape the interphase layers on the electrodes, cut gas formation or reduce flammability. This collection lists additives together with the solvents, ionic liquids and salts used to formulate test electrolytes.
Film-forming additives are the most common starting point. Fluoroethylene carbonate (FEC) helps build a stable SEI on silicon and lithium metal anodes, and vinylene carbonate (VC) does the same on graphite. Fluorinated ethers such as 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether serve as diluents for localized high concentration electrolytes, and FEMC is a fluorinated carbonate cosolvent. Ethoxy(pentafluoro)cyclotriphosphazene is used as a flame-retardant additive.
Base solvents include 4N EC, PC and DEC and 3N DMC for carbonate electrolytes, plus DME and DOL for ether electrolytes in lithium-sulfur and lithium metal cells. Ionic liquids with the EMIM cation, TEABF4 salt for supercapacitors, LATP powder and Li2ZrO3 round out the range. See Electrolyte Additives for Battery Performance and Longevity.
Frequently Asked Questions
Which electrolyte additive should I start with?
For graphite anodes, VC is a common first choice. For silicon or lithium metal anodes, FEC is widely used, such as the 3N5 fluoroethylene carbonate. Additive levels are usually a few percent by weight. Run a control cell without the additive to see its effect.
Which solvents do I need for a carbonate electrolyte?
Most lithium-ion electrolytes mix a cyclic carbonate, such as 4N ethylene carbonate, with a linear carbonate such as DMC or DEC to lower viscosity. PC suits low-temperature blends and graphite-free cells. Dissolve the lithium salt in the dried solvent mix inside a glove box.
When should I use ether solvents like DME and DOL?
Ether electrolytes are standard for lithium-sulfur cells and are common in lithium metal studies, since they are more stable against lithium than carbonates. A DOL and DME mix is a typical base. They are less stable at high voltage, so they suit low-voltage cathodes. See DOL.
What are fluorinated ethers used for?
Fluorinated ethers dissolve little salt themselves, so they act as diluents. Adding them to a concentrated electrolyte keeps the salt clustered near the solvent while lowering viscosity and the total amount of salt needed. This is called a localized high concentration electrolyte. Options include 1,2-(1,1,2,2-tetrafluoroethoxy)ethane.
How should I store electrolyte solvents and additives?
Water and air degrade electrolytes and react with lithium salts. Keep bottles sealed, store and open them in an argon glove box, and use dried molecular sieves where suitable. VC and some additives are sensitive to heat and light, so keep them cool and check the listing for storage guidance.
Can I order a custom electrolyte additive or larger amounts?
Yes. We customize products to meet specific requirements. Send the compound, purity and quantity through the quote request form. For larger amounts of a listed additive or solvent, use the bulk order request form.
