spore: profile id: lithium-hexafluorophosphate spore_version: 0.2 family: lithium name: Lithium hexafluorophosphate abbreviation: LiPF6 role: conducting salt (electrolyte) category: energy type: electrolytes summary: | Lithium hexafluorophosphate (LiPF6) is the lithium salt dissolved in the organic carbonate liquids of most lithium-ion cells, where it carries lithium ions between the electrodes. A 1.0 M solution in ethylene carbonate and dimethyl carbonate (1:1 by weight) conducts about 10.8 to 12.9 mS/cm at 20 to 30 degC, but conductivity collapses below 0.1 mS/cm under -20 degC in a similar commercial mixture. The salt is unstable: dry, it splits into LiF and PF5 gas, and with water it gives HF and POF3, which is why cells that burn can release 20 to 200 mg of HF per Wh. best_for: A conductive, widely used salt for carbonate electrolytes (10.8 to 12.9 mS/cm for a 1.0 M solution at 20 to 30 degC) weakest_at: 'Heat and moisture: it decomposes from about 380 K dry, earlier with water, and gives off toxic HF' identity: formula: LiPF6 cas: 21324-40-3 source: pubchem-lipf6 where: Compound record CID 23688915 (formula F6LiP, CAS 21324-40-3); the supplier safety data sheet (Stanford Advanced Materials) section 1 gives the same CAS tags: environments: [] stresses: - extreme-cold - extreme-heat - thermal-cycling applications: - batteries properties: - benchmark: molar_mass label: Molar mass value: 151.9 unit: g/mol scope: material conditions: basis: computed from the formula F6LiP, not measured computed_by: PubChem 2.2 method: Value computed by PubChem from the molecular formula status: calculated source: pubchem-lipf6 where: Computed Properties > Molecular Weight - benchmark: density label: Density of the solid salt value: 1.5 unit: g/cm3 scope: material conditions: temperature: 25 degC form: solid salt listing: PAC Chemical Database (US Department of Energy), reproduced in PubChem method: Value listed in a database record (measurement method not stated) status: ground note: The Stanford Advanced Materials safety data sheet also lists 1.5 g/cm3 at 20 degC. Both are one-digit values. source: pubchem-lipf6 where: Experimental Properties > Density - benchmark: melting_point label: Melting point (with decomposition) value: 200 unit: degC scope: material conditions: form: powder marked: (dec), meaning it decomposes atmosphere: not stated method: Value listed in the supplier safety data sheet status: ground note: PubChem also lists 200 degC (from the DOE PAC database). The thermogravimetry papers below find dry LiPF6 already splitting into LiF and PF5 at far lower temperatures (380 K, about 107 degC, in Yang et al.), so 200 degC is not a stability limit. source: sa-sds where: Section 9, Melting point/Melting range - benchmark: salt_stability_limit_dry label: Highest temperature at which dry LiPF6 is stable value: 380 unit: K bound: lower scope: material conditions: sample: neat LiPF6 salt atmosphere: dry inert carrier gas, water below 10 ppm method_rate: TGA at 10 K/min decomposition_product: LiF solid and PF5 gas (LiPF6 to LiF + PF5) method: Thermogravimetric analysis with on-line FTIR of the gases status: ground note: The abstract states the salt is stable up to 380 K. In the text, dry isothermal runs showed no mass change in 1 h at 343 K or 363 K, and 3.2% mass loss after one more hour at 383 K. FTIR showed PF5 as the only gas-phase product from 380 to 540 K. source: yang2006 where: Abstract; Results (TG of LiPF6 at isothermal conditions, Fig. 4) - benchmark: mass_loss_383k_dry_1h label: Mass lost by dry LiPF6 after one hour at 383 K value: 3.2 unit: '% of initial mass' scope: material conditions: sample: neat LiPF6 salt atmosphere: dry gas, water below 10 ppm history: no mass change in 1 h at 343 K or in 1 h at 363 K before this hour temperature: 383 K method: Isothermal thermogravimetry status: ground note: The paper reads the isothermal onset of about 383 K as agreeing with the non-isothermal run. Mass-loss reporting error in the paper is +/-1%. uncertainty: +/-1% mass-loss reporting error stated in the Experimental section source: yang2006 where: Results, isothermal TG paragraph (Fig. 4); Experimental - benchmark: salt_onset_dry_tgams label: Decomposition onset of dry LiPF6 (TGA-MS) value: 165 unit: degC scope: material conditions: sample: about 150 mg LiPF6 in a sapphire crucible, dried at 70 degC for 18 h protocol: 1 h hold at 120 degC in dry Ar, then ramp of 10 K/min to 350 degC detection: mass loss and mass-spectrometer gas signals method: Thermogravimetry coupled to mass spectrometry status: ground note: Mass loss was 83%, equal to the theoretical loss for full conversion to LiF (Eq. 1 of the paper). The paper also states, from the literature, that dry LiPF6 thermal dissociation occurs between 100 and 200 degC depending on conditions, and the 165 degC figure is higher than the 380 K (about 107 degC) of Yang et al., so the onset depends on the pre-treatment, holds and detection. source: solchenbach2018 where: Results, Thermal decomposition of dry and wet LiPF6 (Fig. 2); Conclusions - benchmark: salt_onset_wet_tgams label: Decomposition onset of water-exposed LiPF6 (TGA-MS) value: 90 unit: degC scope: material conditions: sample: LiPF6 pre-exposed for 1 h to water-saturated Ar (dew point about 20 degC), mass gain about 24% protocol: ramp of 10 K/min to 350 degC product: POF3 only, no PF5 signal method: Thermogravimetry coupled to mass spectrometry status: ground note: About 75 degC below the dry salt. Final mass loss was only 49% against 83% for dry LiPF6, which the authors attribute to formation of LiPO2F2. HF could not be traced in their set-up because its mass overlaps with argon. source: solchenbach2018 where: Results, Thermal decomposition of dry and wet LiPF6 (Fig. 3); Conclusions - benchmark: onset_shift_300ppm_water label: Lowering of the decomposition onset by 300 ppm water vapour value: 27 unit: K scope: material conditions: sample: neat LiPF6 salt carrier_gas: argon with 300 ppm water vapour, against dry gas below 10 ppm rate: 10 K/min method: Derivative thermogravimetry (DTG) onset, with on-line FTIR showing HF and POF3 before PF5 status: ground note: The paper states the onset drops by ca. 27 K and concludes that the water reaction forms POF3 and HF directly, LiPF6 + H2O to LiF + POF3 + 2HF. source: yang2006 where: Results, TG of neat LiPF6 (Fig. 1, inset); FTIR section (Fig. 3 inset) - benchmark: residual_mass_lif_dry label: Mass remaining after dry LiPF6 decomposed value: 17.1 unit: '% of initial mass' scope: material conditions: sample: neat LiPF6 salt atmosphere: dry carrier gas end_of_run: about 530 K, 10 K/min method: Thermogravimetry status: ground note: The authors say this matches the calculated LiF to LiPF6 mass ratio for LiPF6 giving LiF + PF5. source: yang2006 where: Results, FTIR and TG section (text after Fig. 3) - benchmark: hydrolysis_none_seen_to_temp label: Highest temperature with no detected hydrolysis of LiPF6 in a wet EC electrolyte value: 40 unit: degC bound: lower scope: material conditions: electrolyte: 1.5 M LiPF6 in ethylene carbonate with 5000 ppm H2O steps: 10, 25, 40, 60 degC for 3 h each, then 80 degC for 12 h detection: online mass spectrometry of POF3 and CO2 method: Online electrochemical mass spectrometry (OEMS) of the headspace status: ground note: At 60 degC and above POF3 was seen (below 2000 ppm) and CO2 above 12000 ppm at 60 and 80 degC. The abstract concludes the kinetics for the hydrolysis of LiPF6 with water at room temperature are too slow to be detectable, and that acidic species made by solvent oxidation, not water alone, shift PF6- to PF5 and HF. 5000 ppm methanesulfonic acid gave about 1000 ppm POF3 at 25 degC. source: solchenbach2018 where: Abstract; Results, Fig. 7b and 7c - benchmark: ionic_conductivity label: Ionic conductivity, 1.0 M LiPF6 in EC:DMC (1:1 w:w) value: 10.8 value_high: 12.9 bound: range unit: mS/cm scope: material conditions: solvent: 'ethylene carbonate : dimethyl carbonate 1:1 by weight' concentration: 1.0 M LiPF6 temperature: 20 to 30 degC cell: Pt microelectrode conductivity cell (rhd TSC 1600), cell constant 20 +/- 0.2 per cm method: Impedance spectroscopy (85 kHz to 1 kHz, 100 mV) status: ground uncertainty: error bars of 3% for the cell constant, filling and fitting (Fig. 8 caption) note: The paper compares this with 11.9 mS/cm at 25 degC from Farkhondeh et al. and with the BASF specification sheet for LP30 and LP57 (Supporting Information Fig. S2), and finds good agreement. This is a research-grade electrolyte, not a space-qualified one. source: landesfeind2019 where: Results, Concentration and temperature dependent description of kappa (page A3090); Fig. 8a - benchmark: ionic_conductivity_50c label: Ionic conductivity, 1.0 M LiPF6 in EC:DMC (1:1 w:w), warm value: 17 unit: mS/cm scope: material conditions: solvent: EC:DMC 1:1 by weight concentration: 1.0 M LiPF6 temperature: +50 degC reading: stated as about 17 mS/cm, the top of the range for all electrolytes measured method: Impedance spectroscopy in a Pt microelectrode conductivity cell status: ground note: The paper writes the figure with a tilde (about 17 mS/cm). Highest conductivities occur between about 0.75 M at -10 degC and about 1 M at +50 degC. source: landesfeind2019 where: Results, text on conductivity (page A3090); Fig. 8a - benchmark: ionic_conductivity_3m_cold label: Ionic conductivity, 3.0 M LiPF6 at -10 degC (lowest of the measured range) value: 0.5 unit: mS/cm scope: material conditions: concentration: 3.0 M LiPF6 temperature: '-10 degC' solvents: the paper states this as the low end of the range for its three solvent mixtures (EC:DMC, EC:EMC, EMC:FEC); the exact solvent is not named in the sentence method: Impedance spectroscopy in a Pt microelectrode conductivity cell status: ground note: Shows that more salt does not mean more conductivity. Highest conductivity sits near 0.75 to 1 M. source: landesfeind2019 where: Results, text on conductivity (page A3090); Fig. 8 - benchmark: conductivity_peak_concentration label: Salt concentration giving the highest conductivity (EC:DMC and EC:EMC) value: 0.75 value_high: 1 bound: range unit: mol/L scope: material conditions: solvents: EC:DMC 1:1 w:w and EC:EMC 3:7 w:w temperature: about 0.75 M at -10 degC, about 1 M at +50 degC range_tested: 0.1 to 3.0 M LiPF6 method: Impedance spectroscopy in a Pt microelectrode conductivity cell status: ground note: The EC-free electrolyte (EMC:FEC 19:1 w:w) peaked at higher concentration, about 1.25 M at -10 degC to about 1.6 M at +50 degC. source: landesfeind2019 where: Results, text on conductivity (page A3090); Fig. 8 - benchmark: conductivity_cold_upper_bound label: Ionic conductivity of a commercial 1 M LiPF6 EC/DMC electrolyte below -20 degC value: 0.1 unit: mS/cm bound: upper scope: material conditions: electrolyte: commercial reference electrolyte, 1 M LiPF6 in EC/DMC 1:1 (the paper's Com. Ele.) temperature: below -20 degC sweep: '-90 to 70 degC in 10 degC steps' method: DC conductivity from a broadband dielectric/impedance spectrometer (Novocontrol) status: ground note: The text only gives the upper bound ('generally lower than 0.1 mS/cm'); exact points are in Fig. 1A and were not read. Read through a web summary of the open article, not from the PDF. source: zhao2020 where: Results, Regulating Kinetics of Electrolytes by the Solvent; Fig. 1A; Methods - benchmark: min_service_temp label: Lowest temperature in NASA/JPL low-temperature cell tests with 1.0 M LiPF6 electrolytes value: -70 unit: degC scope: cell conditions: electrolyte: 1.0 M LiPF6 in five alkyl-carbonate/ester mixtures (1EC+1EMC+8MB, 8EB, 8MP, 1EC+1EMC+8EV, 1EC+9EMC by volume) cell: carbon anode, LiNi0.8Co0.2O2 cathode statement: improved performance in cells at temperatures as low as -70 degC method: Low-temperature electrical performance tests of laboratory Li-ion cells, as summarised in a NASA Tech Brief status: ground note: A cell result, not a property of the salt. The brief says the cells with the MB and MP mixtures performed best. No capacity or rate figures are given in the brief. Not a flight result. source: nasa-techbrief-2005 where: Tech Brief 'Ester-Based Electrolytes for Low-Temperature Li-Ion Cells' (NPO-41097), page 25 - benchmark: hf_emitted_in_cell_fire label: Hydrogen fluoride released when commercial Li-ion cells burned value: 20 value_high: 200 bound: range unit: mg/Wh of nominal energy scope: cell conditions: cells: seven types of commercial Li-ion batteries, all electrolytes contained LiPF6 state_of_charge: 0 to 100% (several SOC values) test: fire test with real-time FTIR, cross-checked with gas-washing bottles per_type_ranges: type A 15-25, type B 150-198, type G 15 mg/Wh in Table 2 method: Fire tests of cells with FTIR and gas-washing measurements of HF status: ground note: HF can also come from fluorine in binders, separators and flame retardants, not only LiPF6; the paper says the electrolyte is typically the primary fluorine source. The abstract gives the range as 20 to 200 mg/Wh, while Table 2 rows start lower (as low as 12 mg/Wh for type D). source: larsson2017 where: Abstract; Table 2; Results (Fig. 2a) - benchmark: pof3_emitted_in_cell_fire label: Phosphoryl fluoride (POF3) released in some cell fire tests value: 15 value_high: 22 bound: range unit: mg/Wh of nominal energy scope: cell conditions: cells: commercial Li-ion cells containing LiPF6 test: fire tests with FTIR, measured in some tests only method: Fire tests with FTIR status: ground source: larsson2017 where: Abstract; Results (POF3 paragraph) corrosion: - environment: Water and moisture headline: Water makes LiPF6 give off HF and POF3; in a cell electrolyte at room temperature this reaction was too slow to detect. effect: The supplier safety data sheet names water and moisture as incompatible, says the product is moisture sensitive and lists hydrogen fluoride as a hazardous decomposition product. In thermogravimetry, 300 ppm water vapour lowered the decomposition onset by ca. 27 K and gave HF and POF3. In a wet 1.5 M LiPF6 in ethylene carbonate electrolyte with 5000 ppm H2O, no POF3 was seen up to 40 degC, but acids (methanesulfonic acid) quickly pushed PF6- toward PF5 and HF. rating: moderate conditions: sds: Stanford Advanced Materials, revised 17 November 2022, section 10 thermogravimetry: 300 ppm water vapour, 10 K/min electrolyte_test: 5000 ppm H2O in 1.5 M LiPF6 in EC, up to 80 degC source: sa-sds where: Sections 7 and 10; Yang et al. Abstract and Fig. 1; Solchenbach et al. Fig. 7 - environment: Acids and oxidising agents headline: The safety data sheet lists acids, oxidising agents and heat as incompatible. effect: Section 10 lists acids, water/moisture, oxidising agents and heat as incompatible materials, and the salt reacts with strong oxidising agents. No rate or test is given. rating: unknown conditions: basis: supplier safety data sheet, no quantitative test source: sa-sds where: Section 10 risks: hazards: - text: 'PubChem aggregates 296 reports from 22 ECHA C&L Inventory notifications: signal word Danger. H314 (causes severe skin burns and eye damage) is given by 100% of notifiers, H372 (damage to organs through prolonged or repeated exposure) by 81.8%, H301 (toxic if swallowed) by 79.7%, H318 (serious eye damage) by 69.9%, H302 (harmful if swallowed) by 20.3% and H311 (toxic in contact with skin) by 16.2%. The classifications differ between notifiers.' ghs: - H314 - H372 - H301 - H318 - H302 - H311 source: pubchem-lipf6 where: Safety and Hazards > Hazards Identification > GHS Classification (aggregated ECHA C&L data) - text: The Stanford Advanced Materials safety data sheet (revised 17 November 2022) classifies it as Acute Tox. 3 (H311), Skin Corr. 1B (H314), Eye Dam. 1 (H318) and Acute Tox. 4 (H302), signal word Danger, with pictograms GHS05 and GHS06. It says swallowing causes strong corrosion of mouth and throat with danger of perforation, and skin contact is dangerous through absorption. It lists no LD50/LC50 data and, unlike PubChem, 'No effects known' for repeated-exposure organ toxicity. ghs: - H302 - H311 - H314 - H318 source: sa-sds where: Sections 2 and 11 - text: The salt is not flammable but if involved in a fire it releases hydrogen fluoride, phosphorus oxides and lithium oxide. Firefighters need a self-contained respirator and a fully protective impervious suit. ghs: [] source: sa-sds where: Sections 5 and 10 failure_risks: - mode: Hydrogen fluoride and POF3 release when a cell burns trigger: Fire of a commercial Li-ion cell whose electrolyte contains LiPF6 consequence: Fire tests of seven commercial cell types measured 20 to 200 mg of HF per Wh of nominal capacity, plus 15 to 22 mg/Wh of POF3 in some tests. The authors say fluoride gas emission can pose a serious toxic threat, notably for large battery packs and confined spaces such as a spacecraft. severity: high source: larsson2017 where: Abstract; Introduction; Table 2 - mode: Thermal decomposition of the salt trigger: Heating the dry salt to about 380 K or more, or earlier if water or acid is present consequence: LiPF6 splits into solid LiF and PF5 gas; with 300 ppm water the onset falls by ca. 27 K and HF and POF3 form first. In thermogravimetry on wet salt the onset was about 90 degC. severity: moderate source: yang2006 where: Abstract; Results; Solchenbach et al. Fig. 3 - mode: Acid-driven breakdown inside the electrolyte trigger: Acidic species, for example from oxidation of ethylene carbonate or an added strong acid consequence: Protons shift PF6- toward PF5 and HF; 5000 ppm methanesulfonic acid in EC with 1.5 M LiPF6 gave POF3 near 1000 ppm at 25 degC and about 11000 ppm at 80 degC. severity: moderate source: solchenbach2018 where: Results, Fig. 7b and Abstract - mode: Loss of conductivity when cold trigger: Cooling a 1 M LiPF6 EC/DMC electrolyte below -20 degC consequence: The commercial reference electrolyte conducted generally less than 0.1 mS/cm below -20 degC, far below the 10.8 to 12.9 mS/cm of a similar 1.0 M solution at 20 to 30 degC. severity: moderate source: zhao2020 where: Results, Fig. 1A side_effects: - text: PF5 produced by dry decomposition reacts with trace water to give POF3, and the authors note PF5 reacts with water in the carrier gas in their set-up, so the gases seen depend on how dry the test was. affects: Interpretation of decomposition measurements source: yang2006 where: Results (FTIR section, text before reaction [1]) - text: In an online mass-spectrometry cell all PF5 was detected as POF3, which the authors treat as an analysis effect, so earlier PF5-versus-POF3 assignments may be affected. affects: Reading of gas-analysis data source: solchenbach2018 where: Results (Figs. 4 and 5) handling: - text: Handle under dry protective gas, keep the container tightly sealed, store under dry inert gas away from water, moisture, heat, acids and oxidising agents. The sheet marks it moisture sensitive and says to refrigerate. source: sa-sds where: Section 7 - text: Work in a properly operating chemical fume hood (average face velocity at least 100 feet per minute); use impervious gloves, for example nitrile rubber 0.11 mm with a stated breakthrough of 480 minutes. source: sa-sds where: Section 8 - text: A Sony product safety data sheet for the US18650VT cell (23 March 2007) lists only 'Lithium Salt' in organic solvent as electrolyte, states the contents of an opened cell can irritate lungs, skin and eyes, and advises not to open, crush or burn the cell. source: sony-sds where: Sections hazardous ingredients, health hazard data, handling mitigations: - text: Take off contaminated clothing at once and rinse skin with water; if in eyes rinse cautiously with water for several minutes and remove contact lenses if easy; store locked up; use a neutralising agent for spills and keep it out of drains. source: sa-sds where: Sections 2 and 6 (P303+P361+P353, P305+P351+P338, P361, P405) uses: - application: batteries device: Conducting salt in the electrolytes of commercial lithium-ion cells example: The LBNL study states LiPF6 is the most widely used salt in the electrolytes for commercial Li-ion cells, and every one of the seven commercial cell types in the Larsson fire study had a LiPF6 electrolyte. source: yang2006 where: Introduction; Larsson et al. Results - application: batteries device: NASA/JPL laboratory Li-ion cells for low-temperature operation example: JPL tested 1.0 M LiPF6 in five carbonate/ester solvent mixtures in cells with carbon anodes and LiNi0.8Co0.2O2 cathodes down to -70 degC (ground tests only). source: nasa-techbrief-2005 where: Tech Brief NPO-41097, page 25 documents: - title: 'PubChem compound record: Lithium hexafluorophosphate (CID 23688915)' type: database url: https://pubchem.ncbi.nlm.nih.gov/compound/23688915 year: 2026 - title: 'Stanford Advanced Materials safety data sheet: Lithium Hexafluorophosphate' type: sds url: https://samaterials.com/tds/1697120063-2019-lithium-hexafluorophosphate-powder-sds.pdf year: 2022 - title: Sony Energy Devices product safety data sheet, US18650VT (23 March 2007) type: sds url: https://support.blackanddecker.com/hc/en-us/article_attachments/360012464837 year: 2007 - title: Thermal Stability of LiPF6 Salt and Li-ion Battery Electrolytes Containing LiPF6 (LBNL) type: paper url: https://www.osti.gov/biblio/898281 year: 2006 - title: Quantification of PF5 and POF3 from Side Reactions of LiPF6 in Li-Ion Batteries (open access) type: paper url: https://iopscience.iop.org/article/10.1149/2.0481813jes year: 2018 - title: Temperature and Concentration Dependence of the Ionic Transport Properties of Lithium-Ion Battery Electrolytes (open access) type: paper url: https://iopscience.iop.org/article/10.1149/2.0571912jes year: 2019 - title: Toxic fluoride gas emissions from lithium-ion battery fires (open access) type: paper url: https://www.nature.com/articles/s41598-017-09784-z year: 2017 - title: 'NASA Tech Briefs, December 2005: Ester-Based Electrolytes for Low-Temperature Li-Ion Cells' type: report url: https://ntrs.nasa.gov/citations/20110016439 year: 2005 - title: USGS Mineral Commodity Summaries 2026, Fluorspar type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf year: 2026 - title: NIST Atomic Weights and Isotopic Compositions (lithium, phosphorus, fluorine) type: database url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Li&ascii=html&isotype=some - title: Lithium hexafluorophosphate (Wikipedia) type: database url: https://en.wikipedia.org/wiki/Lithium_hexafluorophosphate gaps: - The Sony safety data sheet that lists LiPF6 at 2% was not found. The Sony sheet that was opened (US18650VT, 23 March 2007) names only 'Lithium Salt' and gives no percentage, so the 2% figure is not entered. - No ECHA registration dossier or harmonised classification was opened; GHS rests on PubChem's aggregate of ECHA notifications and one supplier safety data sheet, which disagree on repeated-exposure toxicity (H372). - Acute toxicity figures (LD50/LC50) are not given in the supplier sheet ('No data'); none were found. - Exact conductivity values at 25 degC for 1.0 M LiPF6 in EC:EMC 3:7 were only shown as a literature curve; Table II fit parameters of Landesfeind and Gasteiger were not entered. - Conductivity of LiPF6 in the solvent blends used on spacecraft (for example the JPL ester mixtures) was not found; the NASA Tech Brief gives no conductivity or capacity numbers. - No vacuum outgassing, radiation-dose, or flight data for LiPF6 itself was found; every number is ground-laboratory. - The Netzsch application note on electrolyte thermal stability and a DFT preprint arguing that POF3 forms mainly via Li2CO3 were only seen as search snippets, not opened, and are not used. - Solubility in water or in carbonate solvents (g per 100 g) and vapour pressure were not found in an opened source (the safety data sheet says only 'soluble' in water). - Hydrolysis rates at elevated temperature were not quantified beyond the POF3 and CO2 levels read from Solchenbach et al. Fig. 7. - The Zhao et al. conductivity bound and the Solchenbach et al. values were read through a web summary of the open article, not from a downloaded PDF (the publisher blocked automated PDF download for Solchenbach). - No LiPF6 producer, production volume or price was found on an opened page; the USGS fluorspar summary covers the feedstock only. - A source that states the LiF plus PF5 synthesis route was not opened. Wikipedia gives the route as phosphorus pentachloride with lithium fluoride and hydrogen fluoride; Yang et al. give the reverse decomposition (LiPF6 to LiF and PF5). sources: pubchem-lipf6: title: 'PubChem compound record: Lithium hexafluorophosphate (CID 23688915)' id: CID 23688915; CAS 21324-40-3; EC 244-334-7 url: https://pubchem.ncbi.nlm.nih.gov/compound/23688915 year: 2026 kind: database license: public domain (NCBI) sa-sds: title: 'Safety Data Sheet: Lithium Hexafluorophosphate (Stanford Advanced Materials)' id: revised 17 November 2022, accessed 25 August 2023 per the sheet url: https://samaterials.com/tds/1697120063-2019-lithium-hexafluorophosphate-powder-sds.pdf year: 2022 kind: datasheet license: manufacturer document, linked not reproduced sony-sds: title: Product Safety Data Sheet, Sony Energy Devices US18650VT lithium-ion rechargeable battery id: Sony Energy Devices Corp. Koriyama Plant, prepared 23 March 2007 url: https://support.blackanddecker.com/hc/en-us/article_attachments/360012464837 year: 2007 kind: datasheet license: manufacturer document, linked not reproduced yang2006: title: Thermal Stability of LiPF6 Salt and Li-ion Battery Electrolytes Containing LiPF6 id: Yang, Zhuang and Ross, Lawrence Berkeley National Laboratory; OSTI 898281; J. Power Sources 161, 573 (2006) url: https://www.osti.gov/biblio/898281 year: 2006 kind: paper license: US Department of Energy national laboratory report (OSTI) solchenbach2018: title: Quantification of PF5 and POF3 from Side Reactions of LiPF6 in Li-Ion Batteries id: doi:10.1149/2.0481813jes (J. Electrochem. Soc. 165, A3022) url: https://iopscience.iop.org/article/10.1149/2.0481813jes year: 2018 kind: paper license: CC BY 4.0 landesfeind2019: title: Temperature and Concentration Dependence of the Ionic Transport Properties of Lithium-Ion Battery Electrolytes id: doi:10.1149/2.0571912jes (J. Electrochem. Soc. 166, A3079) url: https://iopscience.iop.org/article/10.1149/2.0571912jes year: 2019 kind: paper license: CC BY-NC-ND 4.0 zhao2020: title: Designing electrolytes with polymerlike glass-forming properties and fast ion transport at low temperatures id: doi:10.1073/pnas.2004576117 (PNAS 117, 26053) url: https://pmc.ncbi.nlm.nih.gov/articles/PMC7585027/ year: 2020 kind: paper license: PNAS license (page states 'Published under the PNAS license') larsson2017: title: Toxic fluoride gas emissions from lithium-ion battery fires id: doi:10.1038/s41598-017-09784-z (Scientific Reports 7, 10018) url: https://www.nature.com/articles/s41598-017-09784-z year: 2017 kind: paper license: open access (Creative Commons; exact licence not checked) nasa-techbrief-2005: title: Ester-Based Electrolytes for Low-Temperature Li-Ion Cells (NASA Tech Briefs, December 2005, NPO-41097) id: NASA Tech Briefs December 2005, page 25; NTRS 20110016439 url: https://ntrs.nasa.gov/citations/20110016439 year: 2005 kind: report license: public domain (NASA) usgs-fluorspar-2026: title: Mineral Commodity Summaries 2026, Fluorspar url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf year: 2026 kind: report nist-atomic-weights: title: NIST Atomic Weights and Isotopic Compositions, lithium, phosphorus and fluorine pages url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Li&ascii=html&isotype=some kind: database wiki-lipf6: title: Lithium hexafluorophosphate (Wikipedia, production and chemistry) url: https://en.wikipedia.org/wiki/Lithium_hexafluorophosphate kind: web license: CC-BY-4.0 updated: '2026-10-17' review: status: draft method: assistant checked_values: 18 unreachable: 0 caveats: 6 note: Written by an AI assistant on 2026-10-17. Values from Yang et al., Landesfeind and Gasteiger, Larsson et al., the Stanford Advanced Materials sheet, the Sony sheet and the NASA Tech Brief were read in text extracted from the source PDFs; PubChem values were read from its JSON record. The Solchenbach et al. values and the Zhao et al. bound were read through a web summary of the open article. 6 values carry caveats noted in the file. No values were taken from memory. story: risk_groups: - title: For people level: 3 verdict: Corrosive; toxic; makes HF lead: The pure salt is a corrosive, toxic powder, and it gives off hydrogen fluoride when it meets water or heat. points: - label: The powder line: 'A supplier safety data sheet (revised 17 November 2022) gives signal word Danger: toxic in contact with skin (H311), causes severe skin burns and eye damage (H314), serious eye damage (H318) and harmful if swallowed (H302). PubChem''s aggregated ECHA data also lists H372 (organ damage from repeated exposure) at 81.8% of notifications, which the supplier sheet does not.' - label: Moisture line: The salt is moisture sensitive. With water it gives off hydrogen fluoride (HF) and phosphoryl fluoride (POF3). The sheet lists hydrogen fluoride as a hazardous decomposition product. - label: In a fire line: Fire tests of seven commercial cell types, all with LiPF6 electrolytes, measured 20 to 200 mg of HF per Wh of nominal capacity, and 15 to 22 mg/Wh of POF3 in some tests. The authors name a spacecraft among confined places where this could be a serious threat. - title: If it fails lead: These results come from laboratory heating and fire tests, not from spacecraft failures. points: - label: Heating the salt line: Dry LiPF6 was stable up to 380 K, then split into solid LiF and PF5 gas. With 300 ppm of water vapour the onset dropped by about 27 K and HF and POF3 formed first. - label: Acid in the cell line: In ethylene carbonate with 1.5 M LiPF6, water alone gave no detectable POF3 up to 40 °C, but 5000 ppm of methanesulfonic acid gave about 1000 ppm at 25 °C. The authors conclude acidic species, not water alone, drive the breakdown. - label: Cold line: A commercial 1 M LiPF6 electrolyte in EC and DMC conducted generally less than 0.1 mS/cm below -20 °C. - title: Handling and storage points: - label: Storage line: Handle and store under dry inert gas, tightly sealed, refrigerated, away from water, heat, acids and oxidising agents. - label: Protection line: Use a chemical fume hood and impervious gloves (nitrile rubber 0.11 mm, stated breakthrough 480 minutes). Wash skin and rinse eyes with water if exposed. - label: Spills line: Use a neutralising agent and keep the material out of drains. why: 'Lithium hexafluorophosphate (LiPF6) is a salt: a solid made of lithium ions (Li+) and hexafluorophosphate ions (PF6-), a phosphorus atom surrounded by six fluorine atoms. A lithium-ion cell needs a liquid that lets lithium ions travel between its two electrodes, and the usual recipe is this salt dissolved in organic carbonate solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC). A Lawrence Berkeley paper calls it the most widely used salt in commercial Li-ion cells. It is chosen because the solution conducts well: a 1.0 M solution (one mole of salt per litre) in EC and DMC conducts 10.8 to 12.9 mS/cm at 20 to 30 °C. The weak point is the salt itself. It is chemically fragile, splitting into lithium fluoride (LiF) and phosphorus pentafluoride (PF5) when heated, and making hydrogen fluoride (HF) and POF3 when water or acid is present. That is why cells are kept dry, and why cells that burn can release toxic fluoride gases.' uses: - where: Commercial lithium-ion cells line: LiPF6 is the most widely used salt in the electrolytes of commercial Li-ion cells, according to Yang and colleagues. All seven commercial cell types in a Swedish fire study had LiPF6 electrolytes. - where: NASA low-temperature cells line: NASA's Jet Propulsion Laboratory tested 1.0 M LiPF6 in five carbonate and ester solvent mixtures in cells with carbon anodes and LiNi0.8Co0.2O2 cathodes, reporting improved performance at temperatures as low as -70 °C. These were laboratory cells, not flight batteries. can_do: - label: Conducting lithium ions value: 10.8 to 12.9 mS/cm benchmark: ionic_conductivity line: A 1.0 M solution of LiPF6 in EC and DMC (1:1 by weight) measured 10.8 to 12.9 mS/cm between 20 and 30 °C by impedance spectroscopy, and about 17 mS/cm at +50 °C. Conductivity peaks near 0.75 M at -10 °C and 1 M at +50 °C, and falls to about 0.5 mS/cm at 3.0 M and -10 °C. - label: Staying stable when dry value: Stable to 380 K benchmark: salt_stability_limit_dry line: Neat LiPF6 in dry gas showed no mass change in an hour at 343 K or 363 K, then 3.2% mass loss after another hour at 383 K. The other thermogravimetry study found a decomposition onset of 165 °C after a hold at 120 °C, so the onset depends on the method. - label: Low temperature value: Under 0.1 mS/cm below -20 °C benchmark: conductivity_cold_upper_bound line: A commercial 1 M LiPF6 EC/DMC electrolyte conducted generally less than 0.1 mS/cm below -20 °C. The NASA brief reports better performance in cells with ester-containing mixtures at temperatures as low as -70 °C, with no numbers given. compare: Dry LiPF6 begins to break down at 380 K (about 107 °C) in one study and 165 °C in another, while with water vapour the onset falls by about 27 K in the first and to about 90 °C in the second. The supplier datasheet lists a melting point of 200 °C with decomposition, so none of these studies supports treating 200 °C as a safe limit. No source in this record compares LiPF6 with other lithium salts such as LiBF4 or LiFSI, so no such comparison is made. handling: - Keep it dry and sealed, under dry inert gas, refrigerated, away from heat, acids and oxidising agents. - It is corrosive and toxic; use a fume hood and impervious gloves. - Water and acid give hydrogen fluoride, so keep moisture out of cells and the glovebox. - Fire releases HF; firefighters need a self-contained respirator and a fully protective suit. good_for: - Ion transport. A 1.0 M solution in EC and DMC conducts 10.8 to 12.9 mS/cm at 20 to 30 °C. - Wide use. It is the most widely used salt in commercial Li-ion cell electrolytes, per a Berkeley Lab paper. watch_out: - Heat. Dry salt splits into LiF and PF5 above about 380 K in one study, and earlier if water is present. - Moisture and acid. They give HF and POF3, and 300 ppm of water vapour lowered the onset by about 27 K. - Fire. Burning commercial cells released 20 to 200 mg of HF per Wh. - Cold. Conductivity of a commercial 1 M EC/DMC electrolyte fell below 0.1 mS/cm under -20 °C. verdict: 'LiPF6 is the dependable, highly conductive default salt for carbonate electrolytes, but it is chemically fragile: heat, water and acid turn it into HF and POF3, and its solutions lose most conductivity below -20 °C. All numbers here are ground laboratory results; no flight data for the salt itself was found.' compare_rows: - label: Density benchmark: density scope: material - label: Melting point benchmark: melting_point scope: material - label: Molar mass benchmark: molar_mass scope: material recipe: line: Lithium hexafluorophosphate is one lithium ion (Li+) and one hexafluorophosphate ion (PF6-), which is a phosphorus atom surrounded by six fluorine atoms. Atomic weights are NIST standard values. Wikipedia describes manufacture by reacting phosphorus pentachloride with lithium fluoride and hydrogen fluoride, which gives LiPF6 and hydrogen chloride. Heating or wetting the salt reverses the chemistry toward lithium fluoride and phosphorus pentafluoride, which is why it is kept dry. parts: - name: Lithium symbol: Li atoms: 1 atomic_weight: 6.938 role: The charge carrier that moves between the electrodes. NIST gives lithium as an interval; the lower bound is entered. - name: Phosphorus symbol: P atoms: 1 atomic_weight: 30.974 role: Sits at the centre of the anion, bonded to six fluorines. - name: Fluorine symbol: F atoms: 6 atomic_weight: 18.998 role: Six fluorines surround the phosphorus. They are the source of hydrogen fluoride when the salt meets water. supply: - subject: Fluorspar (calcium fluoride), feedstock for hydrogen fluoride, which is the starting point for LiPF6 abundance: World reserves 330,000 thousand t (2025 table); world mine production 10,000 thousand t in 2025. The US was 100% net import reliant on fluorspar producers: - country: China share_percent: 60 year: 2025 - country: Mongolia share_percent: 15 year: 2025 - country: Mexico share_percent: 15 year: 2025 critical_lists: [] recycling: Primary aluminum producers recycle HF and fluorides from smelting operations. substitutes: - Fluorosilicic acid recovered from phosphate rock processing has been used as an alternative to fluorspar in making aluminum fluoride and HF. source: usgs-fluorspar-2026 where: World Mine Production and Reserves table (2025; shares calculated by Space Mushroom from the 10,000 thousand t world total); Salient Statistics; Domestic Production and Use; Substitutes