Battery electrolytes: Production route
Why the salt, not the solvent, is the hard part
What this tab covers How it is made: the main production routes or, for product families, the main product types and technologies, compared on share of supply, inputs per tonne, plant scale, yield, co-products and unit cost.An electrolyte is a blend, so its routes are the routes to its parts. The salt is the costly, technical part: LiPF6 is made from lithium fluoride and phosphorus pentafluoride in anhydrous HF, and LiFSI (lithium bis(fluorosulfonyl)imide) from sulphamic acid, chlorosulphonic acid and HF. Solvents are made from ethylene oxide, CO2 and methanol. Additives are fine chemicals. Solid-state and semi-solid electrolytes are an emerging alternative, and sodium-ion uses NaPF6.
Routes compared
| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| LiPF6 salt (standard) | the main salt in almost all lithium-ion electrolytes; 259 kt shipped in 2025, about 11% of electrolyte mass (derived) | about 0.8 t HF, 0.24 t Li2CO3 and 0.2 t phosphorus (stoichiometry) | Chinese plants 10-50 kt/yr (indicative); world capacity above 390 kt in 2024 (Fairfield via HF tile) | not published | HCl (PCl5 route), spent HF | price RMB 49,600/t at the July 2025 low; above RMB 170,000/t in Q4 2025 |
| LiFSI salt (co-salt and additive) | not published; growing as a co-salt (indicative) | not published | Chinese plants 5-20 kt/yr (indicative) | not published | HCl, sulphur by-products | several times LiPF6 per tonne (indicative) |
| Carbonate solvents (EC, DMC, EMC, DEC, PC) | about 2.30 Mt shipped in 2025; the leading solvent maker had 22.2% share | ethylene oxide, CO2 and methanol (indicative) | 100-500 kt/yr per complex (indicative) | not published | MEG from the DMC route | prices RMB 4,500-7,000/t in 2025, after lows near RMB 4,000/t in 2022-24 |
| Solid-state and semi-solid electrolytes | very small (indicative) | lithium sulphide, germanium-free sulphides, zirconium and lanthanum oxides (indicative) | pilot (indicative) | not published | H2S risk for sulphides | far above liquid (indicative) |
How each route works
LiPF6 salt (standard)PF5 is generated from phosphorus pentachloride or phosphoric acid with HF, then reacted with lithium fluoride dissolved in anhydrous HF. LiPF6 crystallises, is dried and packed under inert gas. Water must be kept to ppm levels because LiPF6 hydrolyses to HF.
Cheap and well understood; thermally and hydrolytically unstable.
HKEX document (Apr 2026); HF tile; stoichiometry LiFSI salt (co-salt and additive)Bis(chlorosulfonyl)imide is made from sulphamic and chlorosulphonic acid, fluorinated with HF and lithiated. Used at 1-3% as an additive or co-salt (indicative), it improves conductivity, thermal stability and fast charging.
Better stability and conductivity; costlier and corrodes aluminium at high loadings.
Indicative; no LiFSI tonnage found Carbonate solvents (EC, DMC, EMC, DEC, PC)EC is made by inserting CO2 into ethylene oxide; DMC by transesterification of EC (or propylene carbonate) with methanol, co-producing glycol; EMC and DEC follow. Battery grades are distilled to over 99.99% purity.
Commodity-like and petrochemical; flammable and the main fire risk in cells.
HKEX document (Apr 2026) Solid-state and semi-solid electrolytesSulphide (Li6PS5Cl), oxide (LLZO), halide or polymer conductors replace some or all of the liquid. Semi-solid cells are in small Chinese EV production; full solid-state is in pilot lines (indicative).
Safer and denser in principle; manufacturing and cost are unsolved.
Indicative Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.