Propylene carbonate PC

spore: profile
id: propylene-carbonate
spore_version: 0.2
family: lithium
name: Propylene carbonate
abbreviation: PC
role: electrolyte solvent
category: energy
type: electrolytes
summary: |
  Propylene carbonate (PC, C4H6O3) is a colourless, high-permittivity organic liquid used as a solvent for lithium salts. Its melting point of -48.8 degC is far below that of ethylene carbonate (36.4 degC), which is why it attracts interest for cold cells. Its known flaw is that it co-intercalates into graphite and exfoliates it, so it is used only as a minor solvent in graphite cells. A Sony Energy Devices battery safety data sheet lists it among the solvents of a lithium-ion polymer cell.
best_for: A liquid over a very wide range (-48.8 to 241.6 degC) with a dielectric constant of 65.50 at 25 degC
weakest_at: Graphite anodes, where PC-rich electrolytes gave a 60% first-cycle irreversible capacity and graphite exfoliation in one test
identity:
  formula: C4H6O3
  cas: 108-32-7
  source: fisher-sds
  where: Section 1 (CAS-No 108-32-7, synonyms PC, 1,2-Propanediol cyclic carbonate, 4-Methyl-1,3-dioxolan-2-one) and Section 9 (molecular formula C4 H6 O3)
tags:
  environments: []
  stresses: []
  applications:
    - batteries
properties:
  - benchmark: melting_point
    label: Melting point
    value: -48.8
    unit: degC
    scope: material
    conditions:
      basis: pure compound, temperature stated as a single value, no pressure given
      reference_cited_by_pubchem: CRC Handbook of Chemistry and Physics, 95th ed., p. 3-468 (via HSDB)
    method: Handbook value compiled in the PubChem Experimental Properties section
    status: ground
    note: The Fisher safety data sheet lists -49 degC and a Louisiana State University solvent page lists a freezing point of -55 degC. Xiang et al. (2015) quote -48.8 degC for PC against 36.4 degC for ethylene carbonate.
    source: pubchem-pc
    where: Experimental Properties > Melting Point
  - benchmark: boiling_point
    label: Boiling point
    value: 241.6
    unit: degC
    scope: material
    conditions:
      basis: pure compound
      pressure: not stated for this entry; the PAC database entry in the same PubChem section gives 242 degC at 760 mm Hg
      reference_cited_by_pubchem: CRC Handbook, 95th ed., p. 3-468 (via HSDB)
    method: Handbook value compiled in the PubChem Experimental Properties section
    status: ground
    note: The Fisher safety data sheet gives a range of 240 - 243 degC and the LSU page gives 241.7 degC.
    source: pubchem-pc
    where: Experimental Properties > Boiling Point
  - benchmark: flash_point
    label: Flash point
    value: 116
    unit: degC
    scope: material
    conditions:
      method_stated: 'Fisher SDS: ''No information available''; PubChem lists the same 116 degC as closed cup from a Sigma-Aldrich safety data sheet (product 310328)'
    method: Safety data sheet value
    status: ground
    note: Sources disagree. PubChem also lists 135 degC (275 degF, closed cup, NFPA Fire Protection Guide) and the LSU page gives 135 degC closed cup. Wikipedia gives 132 degC but that infobox is uncited and not used here.
    source: fisher-sds
    where: Section 5 and Section 9 (Flash Point 116 degC / 240.8 degF)
  - benchmark: autoignition_temp
    label: Autoignition temperature
    value: 430
    unit: degC
    scope: material
    conditions:
      basis: pure compound, test method not stated in the sheet
    method: Safety data sheet value
    status: ground
    note: Another supplier sheet (Parchem) gave 510 degC in a search snippet; that sheet could not be opened and is not used.
    source: fisher-sds
    where: Section 5 and Section 9
  - benchmark: explosion_limit_lower
    label: Lower explosion limit
    value: 4.7
    unit: vol %
    scope: material
    conditions:
      temperature: 200 degC
      upper_limit: 21 vol % at 200 degC
    method: Safety data sheet value
    status: ground
    source: fisher-sds
    where: Section 5 and Section 9 (Explosion Limits)
  - benchmark: density
    label: Density
    value: 1.2047
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 degC
      reference_cited_by_pubchem: CRC Handbook, 95th ed., p. 3-468 (via HSDB)
    method: Handbook value compiled in the PubChem Experimental Properties section
    status: ground
    note: The LSU page gives 1.2006 g/mL at 20 degC and 1.1951 g/mL at 25 degC. The Fisher sheet gives a specific gravity of 1.204.
    source: pubchem-pc
    where: Experimental Properties > Density
  - benchmark: vapor_pressure
    label: Vapor pressure
    value: 0.045
    unit: mm Hg
    scope: material
    conditions:
      temperature: 25 degC
      reference_cited_by_pubchem: Daubert and Danner, Physical and Thermodynamic Properties of Pure Chemicals (1989), via HSDB
    method: Handbook value compiled in the PubChem Experimental Properties section
    status: ground
    note: The Fisher sheet gives 0.04 mbar at 20 degC.
    source: pubchem-pc
    where: Experimental Properties > Vapor Pressure
  - benchmark: water_solubility
    label: Solubility in water
    value: 175
    unit: g/L
    scope: material
    conditions:
      temperature: 25 degC
      pubchem_value: 1.75e5 mg/L
      reference_cited_by_pubchem: Riddick et al., Techniques of Chemistry, 4th ed., vol. II (1985), p. 434 (via HSDB)
    method: Handbook value compiled in the PubChem Experimental Properties section, converted from mg/L
    status: ground
    note: The Fisher sheet says only 'Soluble in water' and 'Hygroscopic', which matters because water is harmful in lithium-ion electrolytes.
    source: pubchem-pc
    where: Experimental Properties > Solubility
  - benchmark: dielectric_constant
    label: Dielectric constant
    value: 65.5
    unit: dimensionless
    scope: material
    conditions:
      temperature: 25 degC
      comparison_in_same_table: ethylene carbonate 90.50 at 40 degC
    method: Value listed in Table III of a density-functional-theory paper (the table lists it beside calculated orbital energies; the measurement source is not stated in the text we read)
    status: ground
    note: The Louisiana State University page gives 64.9 at 20 degC and a table in a dye-solar-cell review gives 65.0 with no temperature. The paper says ethylene carbonate has a higher dielectric constant and lower viscosity than PC-based electrolyte, which favours salt dissociation.
    source: bhatt2014
    where: Table III
  - benchmark: dielectric_constant_20c
    label: Dielectric constant, second source
    value: 64.9
    unit: dimensionless
    scope: material
    conditions:
      temperature: 20 degC
    method: Value listed on a university solvent reference page that names no original data source
    status: ground
    source: lsu-pc
    where: Page text, dielectric constant line
  - benchmark: viscosity
    label: Viscosity
    value: 2.8
    unit: mPa s
    scope: material
    conditions:
      temperature: 20 degC
      purity: laboratory-grade pure liquid, no salt
    method: Safety data sheet value
    status: ground
    note: A table in a dye-solar-cell review lists 2.5 cP (1 cP = 1 mPa s) with no temperature stated; the LSU page lists none.
    source: fisher-sds
    where: Section 9 (Viscosity 2.8 mPa s @ 20 degC)
  - benchmark: viscosity_review_table
    label: Viscosity, second source
    value: 2.5
    unit: cP
    scope: material
    conditions:
      temperature: not stated in the table
      comparison_in_same_table: dimethyl carbonate 0.59 cP, diethyl carbonate 0.75 cP, ethylene carbonate 1.90 cP
    method: Table of common gel-electrolyte solvents compiled in a review (the table cites its own references 14, 36 and 223)
    status: ground
    note: The review is about dye-sensitised solar cells, not lithium-ion cells. Its ethylene carbonate row (melting point 36.4 degC, dielectric constant 90.0) is used for comparison only.
    source: dssc-review
    where: Table 6
  - benchmark: oral_ld50_rat
    label: Acute oral toxicity (rat)
    value: 29000
    unit: mg/kg
    scope: material
    conditions:
      species: rat
      route: oral
      dermal_rabbit: LD50 above 3000 mg/kg
    method: Safety data sheet value
    status: ground
    source: fisher-sds
    where: Section 11
  - benchmark: first_cycle_irreversible_cap
    label: First-cycle irreversible capacity in a PC-containing electrolyte on graphite
    value: 60
    unit: '%'
    scope: cell
    conditions:
      cell: Li|graphite coin half cell, 2325 type, coated graphite MAG-10
      electrolyte: E1, 1.0 M LiPF6 in EC-PC-EMC 5:2:3 by weight, no additive
      rate: C/20 (0.075 mA/cm2)
      voltage_window: 0.005 to 1.2 V
      comparison: 16% with 0.05 M CsPF6 added, 33% with 2 wt % FEC added, 10 to 12% for 1.0 M LiPF6 in EC-EMC 3:7 by volume with no PC
    method: Galvanostatic lithiation and delithiation of half cells, values quoted in the text
    status: ground
    note: A cell test of an electrolyte that is only 20% PC by weight (2 of 10 parts), not a pure-PC test. The authors link the long plateau above 0.5 V in this cell to extensive PC reduction and graphite exfoliation.
    source: xiang2015
    where: Section 3 (Electrochemical Behavior of Cs+ in the Li|Graphite Half Cells) and Figure 1A
  - benchmark: graphite_nca_capacity_pc
    label: Capacity of a graphite|NCA full cell with a PC electrolyte after formation cycles
    value: 50
    unit: mAh/g
    scope: cell
    conditions:
      cell: graphite|LiNi0.80Co0.15Al0.05O2 coin full cell
      electrolyte: E1, 1.0 M LiPF6 in EC-PC-EMC 5:2:3 by weight, no additive
      voltage_window: 4.3 to 2.5 V
      formation: two cycles at 0.05C, room temperature
    method: Cycling of full cells (Figure 8A); value as stated in the text
    status: ground
    note: The text says the cell delivered a low capacity below 50 mAh/g, attributed to extensive PC reduction and graphite exfoliation (Figure S8, not opened). The number is an upper bound, not a measured value.
    source: xiang2015
    where: Section 3, Cell Performance of Graphite|NCA Full Cells with Cs+; Figure 8A
  - benchmark: li_desolvation_energy
    label: Desolvation energy of Li+(PC)3
    value: 9.55
    unit: kcal/mol
    scope: material
    conditions:
      method: B3LYP/6-31G(d), liquid phase (polarised continuum, tetrahydrofuran dielectric)
      comparison: 6.45 kcal/mol for Li+(EC)3
      solvation_number: n = 3
    method: Density functional theory calculation
    status: calculated
    note: The authors read the higher PC value as making Li+ intercalation from PC solvent harder, and say Li+(PC)3 clusters deform in graphite, favouring co-intercalation and exfoliation over SEI formation.
    source: bhatt2014
    where: Table II
corrosion:
  - environment: "Water and humid air, environmental exposure"
    headline: "PubChem says propylene carbonate may hydrolyse in the environment, with no rate given."
    effect: "The PubChem record states that propylene carbonate may undergo hydrolysis under environmental conditions because it has groups that hydrolyse there. No half-life, rate or product is given in the text read."
    rating: unknown
    conditions: {basis: "general environmental statement; no measured rate"}
    source: pubchem-pc
    where: "Environmental Fate and Exposure, Abiotic degradation"
  - environment: "Storage in air and moisture"
    headline: "Listed as moisture sensitive; keep the container tightly closed in a dry place."
    effect: "The PubChem storage entry lists propylene carbonate as moisture sensitive and in the combustible-liquid storage class (TRGS 510). It gives no time or humidity limit."
    rating: unknown
    conditions: {basis: "storage guidance; no test conditions"}
    source: pubchem-pc
    where: "Handling and Storage, Conditions for safe storage"
  - environment: "Contact with acids and bases"
    headline: "Listed as incompatible with acids and bases."
    effect: "PubChem lists acids and bases as incompatible materials, with no reaction products or rates given. The text read does not describe reaction with lithium metal."
    rating: unknown
    conditions: {basis: "incompatibility list; no test conditions"}
    source: pubchem-pc
    where: "Safety and Hazards, Stability and Reactivity, Hazardous Reactivities and Incompatibilities"
  - environment: "Heating to decomposition"
    headline: "On heating to decomposition it gives off acrid smoke and irritating fumes."
    effect: "PubChem records that heated propylene carbonate decomposes to acrid smoke and irritating fumes. No decomposition temperature is given."
    rating: unknown
    conditions: {basis: "decomposition entry; no temperature"}
    source: pubchem-pc
    where: "Experimental Properties, Decomposition"
risks:
  hazards:
    - text: 'PubChem lists GHS07, signal word Warning and H319, causes serious eye irritation (ECHA C&L Inventory: H319 at more than 99.9%, from 4,143 company reports in 7 notifications; 2 of the 4,143 reports say the criteria are not met). Precautionary codes listed: P264+P265, P280, P305+P351+P338, P337+P317.'
      ghs:
        - H319
      source: pubchem-pc
      where: Safety and Hazards > GHS Classification
    - text: A Fisher Scientific safety data sheet (revision 17 January 2018) classifies it as serious eye damage/eye irritation category 2, signal word Warning, 'Causes serious eye irritation'. Acute oral LD50 in rat 29000 mg/kg; dermal LD50 in rabbit above 3000 mg/kg.
      ghs:
        - H319
      source: fisher-sds
      where: Sections 2 and 11
    - text: 'Combustible liquid: flash point 116 degC, autoignition 430 degC, explosion limits 4.7 to 21 vol % at 200 degC. Thermal decomposition can release irritating gases; combustion gives carbon monoxide and carbon dioxide.'
      ghs: []
      source: fisher-sds
      where: Sections 5 and 9
    - text: 'Sony Energy Devices cell safety data sheet (issue date 2020-01-01): batteries are treated as articles not subject to GHS; electrolyte solvents (which may include propylene carbonate) are 5-20% of the cell; fires may produce toxic, corrosive or irritating fumes including HF; cells should not be opened, crushed, burned or exposed to high temperatures (above 60 degC).'
      ghs: []
      source: sony-sds
      where: Sections 2, 3, 5 and 7
  failure_risks:
    - mode: Graphite exfoliation and failed SEI formation
      trigger: First charge of a graphite anode in a PC-rich electrolyte without a film-forming additive
      consequence: Solvated Li+ co-intercalates into the graphite, which is destroyed by exfoliation. In the test cell with 2 parts PC in 10, first-cycle irreversible capacity was 60% and the graphite|NCA full cell delivered below 50 mAh/g after formation.
      severity: high
      source: xiang2015
      where: Abstract; Section 3
    - mode: Poor low-temperature range from replacing PC with ethylene carbonate
      trigger: Using ethylene carbonate (melting point 36.4 degC) as the SEI-forming solvent
      consequence: The authors say the high melting point of EC narrows the service temperature range of most lithium-ion cells; PC melts at -48.8 degC.
      severity: moderate
      source: xiang2015
      where: Section 1
  side_effects:
    - text: Pure PC is hygroscopic according to the Fisher sheet and dissolves 175 g/L of water at 25 degC (PubChem). Water uptake is a general concern for lithium-ion electrolytes, but this record holds no measurement of its effect.
      affects: Handling and storage of the solvent
      source: fisher-sds
      where: Section 10 (Stability, hygroscopic)
  handling:
    - text: Keep away from heat and sources of ignition. Extinguish with water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
      source: fisher-sds
      where: Section 5
uses:
  - application: batteries
    device: Lithium-ion polymer cell (Sony Energy Devices, product FT40)
    example: The sheet lists electrolyte solvent as one or more of ethylene carbonate, diethylcarbonate, dimethylcarbonate, ethylmethylcarbonate and propylene carbonate (CAS 108-32-7), 5-20% of the cell, with graphite and/or carbon negative electrode and lithiated cobalt/manganese oxides as positive electrode.
    source: sony-sds
    where: Section 3
  - application: batteries
    device: Graphite|NCA coin cells (ground research, not a product)
    example: PNNL and Army Research Laboratory researchers used EC-PC-EMC electrolytes with Cs+ additive to protect graphite, and report low-temperature discharge improvements down to -40 degC. The paper says PC use in commercial electrolytes is restricted to below 10%.
    source: xiang2015
    where: Section 1; Section 3 and conclusion
supply:
  - subject: "Propylene oxide and carbon dioxide (feedstocks)"
    abundance: "Propylene oxide is made from propylene by a chlorohydrin route or an oxidation route; in 2005 about half of world propylene oxide was made by each, and the oxidation route was growing. Carbon dioxide is the second feedstock of the carbonation reaction. No production volume or country share for propylene carbonate was read."
    producers: []
    critical_lists: []
    recycling: "Not sourced."
    substitutes: []
    source: wikipedia-po
    where: "Propylene oxide, Production (chlorohydrin route and oxidation of propylene); Propylene carbonate, Preparation"
documents:
  - title: 'PubChem compound record: Propylene carbonate (CID 7924)'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/7924
    year: 2026
  - title: 'Fisher Scientific safety data sheet: Propylene carbonate (O4331-4, revision 17 January 2018)'
    type: sds
    url: https://msds.nipissingu.ca/Inventory/Home/DownloadFile/955
    year: 2018
  - title: 'Sony Energy Devices safety data sheet: FT40 lithium ion polymer battery (issue 2020-01-01)'
    type: sds
    url: https://static.lenovo.com/ww/docs/regulatory/msds/FT40-Sony-SDS.pdf
    year: 2020
  - title: The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes
    type: paper
    url: https://doi.org/10.1021/acsami.5b05552
    year: 2015
  - title: The Role of Carbonate and Sulfite Additives in Propylene Carbonate-Based Electrolytes on the Formation of SEI Layers at Graphitic Li-Ion Battery Anodes (open access)
    type: paper
    url: https://hdl.handle.net/10468/6107
    year: 2014
  - title: Progress on Electrolytes Development in Dye-Sensitized Solar Cells (open access, Table 6)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC6631186/
    year: 2019
  - title: "NIST Atomic Weights and Isotopic Compositions for All Elements"
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl
    year: 2026
gaps:
  - 'Reactivity of propylene carbonate with lithium metal: no sourced data read in this run; PubChem lists only acids and bases as incompatible.'
  - 'The user''s note that a Sony safety data sheet lists propylene carbonate at 4% was not confirmed: the Sony Energy Devices FT40 sheet found lists propylene carbonate only as one of five possible solvents, 5-20% in total, with no individual percentage. A sheet showing 4% was not located.'
  - No low-temperature performance figure specific to PC (conductivity, capacity retention or discharge at a stated temperature) was read. Xiang et al. state improved discharge down to -40 degC with a Cs+ additive, but the numbers sit in figures and supplementary data that were not opened.
  - Viscosity and dielectric constant are not in PubChem; the viscosity has one dated, lab-grade source (Fisher, 20 degC) and one table without temperature. The measurement source of the 65.50 dielectric constant in Bhatt and O'Dwyer is not stated in the text read.
  - The flash point differs by source (116, 135 and 132 degC) and the test method is not stated for the 116 degC value.
  - No ionic conductivity of a PC/LiPF6 solution, no electrochemical stability window, and no thermal-runaway data for PC electrolytes were read.
  - No outgassing, vacuum or radiation data for PC were found or looked for; no spaceflight use of PC in a cell was found.
  - The ECHA registration dossier itself was not opened; GHS data come from the PubChem aggregate of the ECHA C&L Inventory.
  - Classic exfoliation papers (Dahn and Fong 1990; Aurbach) and the Journal of Power Sources AFM study were not opened; the exfoliation account rests on Xiang et al. 2015 and Bhatt and O'Dwyer 2014.
  - Wikipedia's statement that PC is not used in lithium-ion batteries cites an Aurbach book that was not read, and is not used for any value.
sources:
  pubchem-pc:
    title: PubChem compound record, Propylene carbonate (CID 7924), Experimental Properties and GHS Classification
    id: CID 7924; CAS 108-32-7
    url: https://pubchem.ncbi.nlm.nih.gov/compound/7924
    year: 2026
    kind: database
    license: public domain (NCBI)
  fisher-sds:
    title: 'Safety Data Sheet: Propylene carbonate, Fisher Scientific cat. O4331-4'
    id: revision 17 January 2018, revision number 3 (copy hosted by Nipissing University)
    url: https://msds.nipissingu.ca/Inventory/Home/DownloadFile/955
    year: 2018
    kind: datasheet
    license: manufacturer document, linked not reproduced
  sony-sds:
    title: 'Safety Data Sheet: FT40, Lithium Ion Polymer Battery (Sony Energy Devices Corporation)'
    id: issue date 2020-01-01 (copy hosted by Lenovo)
    url: https://static.lenovo.com/ww/docs/regulatory/msds/FT40-Sony-SDS.pdf
    year: 2020
    kind: datasheet
    license: manufacturer document, linked not reproduced
  xiang2015:
    title: The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes
    id: doi:10.1021/acsami.5b05552 (ACS Appl. Mater. Interfaces 2015, 7, 20687-20695; PNNL-hosted copy)
    url: https://www.pnnl.gov/sites/default/files/media/file/at/publications//456_252018112618.pdf
    year: 2015
    kind: paper
    license: American Chemical Society article, linked not reproduced
  bhatt2014:
    title: The Role of Carbonate and Sulfite Additives in Propylene Carbonate-Based Electrolytes on the Formation of SEI Layers at Graphitic Li-Ion Battery Anodes
    id: doi:10.1149/2.0931409jes (J. Electrochem. Soc. 161(9) A1415-A1421; UCC repository copy)
    url: https://hdl.handle.net/10468/6107
    year: 2014
    kind: paper
    license: CC BY-NC-ND 4.0
  lsu-pc:
    title: Propylene Carbonate (solvent reference page, Louisiana State University)
    id: macro.lsu.edu solvent how-to page
    url: https://macro.lsu.edu/HowTo/solvents/Propylene%20Carbonate.htm
    year: 2026
    kind: web
    license: university web page, linked not reproduced
  dssc-review:
    title: Progress on Electrolytes Development in Dye-Sensitized Solar Cells
    id: Materials 2019, 12, 1998 (PMC6631186), Table 6
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC6631186/
    year: 2019
    kind: paper
    license: CC BY 4.0
  wikipedia-pc:
    title: "Wikipedia: Propylene carbonate (Preparation and Electrolyte sections)"
    url: https://en.wikipedia.org/wiki/Propylene_carbonate
    kind: web
    license: CC BY-SA 4.0
  wikipedia-po:
    title: "Wikipedia: Propylene oxide (Production)"
    url: https://en.wikipedia.org/wiki/Propylene_oxide
    kind: web
    license: CC BY-SA 4.0
  nist-atomic-weights:
    title: "NIST Atomic Weights and Isotopic Compositions for All Elements (standard atomic weight table)"
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl
    year: 2026
    kind: database
    license: public domain (US government work)
license: CC-BY-4.0
updated: '2026-10-17'
review:
  status: draft
  method: assistant
  checked_values: 16
  unreachable: 0
  caveats: 8
  note: Written by an AI assistant on 2026-10-17. Values were read in text extracted from the source PDFs (Fisher SDS, Sony SDS, Xiang 2015, Bhatt 2014) or in PubChem, LSU and Europe PMC pages through a page summary or XML. No values were taken from memory. Several carry caveats noted in the file; the '4% Sony' figure was not confirmed.
story:
  recipe:
    line: "Propylene carbonate is a cyclic carbonate made by carbonating propylene oxide with carbon dioxide: CH3CHCH2O + CO2 gives C4H6O3 (Wikipedia, Preparation)."
    parts:
      - {name: Carbon, symbol: C, atoms: 4, atomic_weight: 12.011, role: "Four carbons: the three-carbon propylene chain and the carbonate carbon. NIST gives a range for natural abundance"}
      - {name: Hydrogen, symbol: H, atoms: 6, atomic_weight: 1.008, role: "Six hydrogens on the ring and methyl group. NIST gives a range for natural abundance"}
      - {name: Oxygen, symbol: O, atoms: 3, atomic_weight: 15.999, role: "Three oxygens: the two ring ether links and the carbonyl oxygen. NIST gives a range for natural abundance"}
  risk_groups:
    - title: For people
      level: 1
      verdict: Eye irritant; combustible
      lead: Pure propylene carbonate is classified as a serious eye irritant and is otherwise of low acute toxicity in the sheets read.
      points:
        - label: Eyes
          line: PubChem lists H319 (causes serious eye irritation) with signal word Warning, from an ECHA notification count of 4,143 reports. The Fisher sheet classifies it as eye irritation category 2.
        - label: Swallowing and skin
          line: The Fisher sheet gives an oral LD50 of 29000 mg/kg in rat and a dermal LD50 above 3000 mg/kg in rabbit.
        - label: Fire
          line: Flash point 116 degC and autoignition 430 degC on the Fisher sheet; explosion limits 4.7 to 21 vol % at 200 degC. Combustion gives carbon monoxide and carbon dioxide.
    - title: If it fails
      lead: The failure on record is chemical and happens inside a cell, not a spill hazard.
      points:
        - label: On graphite
          line: In a half cell with a PC-containing electrolyte and no additive, first-cycle irreversible capacity was 60%, and the paper links the plateau above 0.5 V to PC reduction and graphite exfoliation.
        - label: In a full cell
          line: A graphite|NCA full cell with the same electrolyte delivered below 50 mAh/g after formation cycles.
        - label: In a fire
          line: The Sony sheet warns that fires involving the cells may produce toxic, corrosive or irritating fumes including HF.
    - title: Handling and storage
      points:
        - label: Keep dry
          line: The Fisher sheet calls the liquid hygroscopic; PubChem lists 175 g/L solubility in water at 25 degC.
        - label: Heat and ignition
          line: Keep away from heat and ignition sources. Water spray, alcohol-resistant foam, dry chemical or carbon dioxide put out a fire.
        - label: Finished cells
          line: The Sony sheet says not to open, crush or burn cells or expose them to high temperatures (above 60 degC).
  why: 'Propylene carbonate (PC) is a cyclic carbonate ester, a small ring molecule with the formula C4H6O3. It is a clear liquid over a very wide range, from a melting point of -48.8 degC to a boiling point of 241.6 degC. Its dielectric constant, which measures how well a liquid separates salts into ions, is 65.50 at 25 degC. That makes it a good solvent for lithium salts. Its lab-grade viscosity is 2.8 mPa s at 20 degC, thicker than the linear carbonates it is mixed with. PC matters in cold-cell work because ethylene carbonate (EC), the usual solvent that builds a protective film on graphite, melts at 36.4 degC and so narrows the temperature range of most cells. PC melts far lower, but its own flaw is documented: it co-intercalates into graphite (solvent molecules wedge between the graphite layers along with lithium ions) and exfoliates it, so it is used only as a minor part of the solvent mix.'
  uses:
    - where: Solvent in a Sony lithium-ion polymer cell
      line: The Sony Energy Devices FT40 safety data sheet lists propylene carbonate (CAS 108-32-7) as one of five possible electrolyte solvents, 5-20% of the cell in total. The sheet gives no separate percentage for PC.
    - where: Research on cold graphite cells
      line: PNNL and Army Research Laboratory researchers used EC-PC-EMC electrolytes with a cesium additive in graphite|NCA coin cells and report better discharge down to -40 degC. They say PC use in commercial electrolytes is restricted to below 10%. These are laboratory cells, not flight hardware.
  can_do:
    - label: Wide liquid range
      value: '-48.8 to 241.6 degC'
      line: PubChem's handbook values give a melting point of -48.8 degC and a boiling point of 241.6 degC. The Fisher sheet gives -49 degC and 240 - 243 degC.
    - label: Dissolving salts
      value: Dielectric constant 65.50
      line: Bhatt and O'Dwyer list 65.50 at 25 degC against 90.50 for ethylene carbonate at 40 degC. The LSU page gives 64.9 at 20 degC.
    - label: Flow
      value: 2.8 mPa s
      line: The Fisher sheet gives 2.8 mPa s at 20 degC. A review table gives 2.5 cP (temperature not stated), against 0.59 cP for dimethyl carbonate and 0.75 cP for diethyl carbonate.
    - label: Cold performance
      value: Not measured here
      line: The low melting point is the sourced evidence. Xiang et al. report low-temperature discharge down to -40 degC with a cesium additive, but no number from their figures was read, so no cold-capacity value is claimed.
  compare: 'Against ethylene carbonate, PC melts at -48.8 degC versus 36.4 degC and so stays liquid in the cold. EC has the higher dielectric constant (90.50 at 40 degC versus 65.50 at 25 degC for PC) and lower viscosity (1.90 cP versus 2.5 cP in the review table). The decisive difference is the graphite film: in the same paper an electrolyte without PC gave 10 to 12% first-cycle irreversible capacity, against 60% with PC and no additive.'
  good_for:
    - Staying liquid in the cold. Melting point -48.8 degC, against 36.4 degC for ethylene carbonate.
    - Dissolving lithium salts. Dielectric constant 65.50 at 25 degC.
    - Low acute toxicity. Oral LD50 of 29000 mg/kg in rat on the Fisher sheet.
  watch_out:
    - Graphite exfoliation. A cell with a PC-containing electrolyte and no additive had 60% first-cycle irreversible capacity and delivered below 50 mAh/g in a full cell.
    - Eye irritation. H319, signal word Warning.
    - Combustible. Flash point 116 degC, though other sources give 135 degC and 132 degC.
    - Moisture. The liquid is hygroscopic.
  verdict: 'Propylene carbonate is a high-permittivity solvent that stays liquid to -48.8 degC, which is why it is studied for cold cells, but on graphite it needs help: without a film-forming additive or a cesium trick it exfoliates the anode, and this record holds no cold-performance number for it and no spaceflight use.'
  compare_rows:
    - label: Density
      benchmark: density
      scope: material
    - label: Melting point
      benchmark: melting_point
      scope: material
    - label: Boiling point
      benchmark: boiling_point
      scope: material