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        "definition": "Formed when LiPF₆ electrolyte meets water, or when a fluorinated cell burns. Inside a cell traces of it attack the positive electrode and SEI; in a fire it is the most dangerous component of the vented gas.",
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        "definition": "A film of electrolyte reaction products on the negative-electrode particles — graphite, and also silicon or lithium metal. It protects the electrode from further reaction but grows slowly for the whole life of the cell, consuming cyclable lithium.",
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          "formation",
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        "definition": "Degradation at one electrode caused by species produced at the other — dissolved transition metals or oxidation products from the positive electrode damaging the SEI on the negative. It is why electrode aging cannot be studied in isolation.",
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        "id": "electrode",
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        "definition": "A solid conductor where the cell’s reaction happens, in contact with the electrolyte. A lithium-ion cell has a negative electrode and a positive electrode, each a porous coating on a metal foil.",
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          "title": "Two transport paths",
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        "definition": "The electrode at the lower potential, usually graphite on copper foil in a lithium-ion cell. It holds the lithium when the cell is charged and releases it on discharge, and industry calls it the anode.",
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          "title": "Keep the polarity name",
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        "url": "https://lemonergy.com/learn/glossary/negative-electrode/",
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        "id": "positive-electrode",
        "name": "Positive electrode",
        "section": "topic-components",
        "definition": "The electrode at the higher potential: a lithium metal oxide or phosphate coated on aluminium foil. It is the lithium source when a cell is built, and industry calls it the cathode.",
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          "title": "Polarity and reaction",
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        "id": "electrolyte",
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          "title": "Ions and electrons",
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        "url": "https://lemonergy.com/learn/glossary/electrolyte/",
        "mentions": [
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      "id": "term:cobalt",
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        "id": "cobalt",
        "name": "Cobalt",
        "section": "topic-sustainability",
        "definition": "The metal that stabilises layered-oxide cathodes, mined largely in the Democratic Republic of Congo under scrutiny for working conditions. Its price and ethics have driven the industry from LCO and NMC111 towards high-nickel and cobalt-free LFP.",
        "related": [
          "nmc",
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        "url": "https://lemonergy.com/learn/glossary/cobalt/",
        "mentions": []
      }
    },
    {
      "id": "term:leaching",
      "type": "Term",
      "label": "Leaching",
      "properties": {
        "id": "leaching",
        "name": "Leaching",
        "aka": [
          "acid leaching",
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        "section": "topic-recycling",
        "definition": "Dissolving the metals in black mass, usually in sulfuric acid with hydrogen peroxide as a reducing agent so cobalt and manganese go into solution as their more soluble lower oxidation state. The leach liquor carries lithium, nickel, cobalt and manganese, plus impurities such as copper and aluminium.",
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          "hydrometallurgy",
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    {
      "id": "term:manganese",
      "type": "Term",
      "label": "Manganese",
      "properties": {
        "id": "manganese",
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          "manganese sulfate",
          "high-purity manganese sulfate",
          "HPMSM"
        ],
        "section": "topic-sustainability",
        "definition": "A cheap, abundant metal used in NMC, LMO and LMFP positive electrodes and in alkaline cells. Ore comes mostly from South Africa, Gabon and Australia, but about 95 % of battery-grade high-purity manganese sulfate was refined in China in 2024, which puts manganese on critical-raw-material lists despite plentiful reserves.",
        "related": [
          "nmc",
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        "url": "https://lemonergy.com/learn/glossary/manganese/",
        "mentions": []
      }
    },
    {
      "id": "lesson:fundamentals/battery-aging/",
      "type": "Lesson",
      "label": "Lesson 4 · Battery aging",
      "properties": {
        "url": "https://lemonergy.com/learn/fundamentals/battery-aging/"
      }
    },
    {
      "id": "reference:edge-degradation",
      "type": "Reference",
      "label": "Lithium ion battery degradation: what you need to know",
      "properties": {
        "title": "Lithium ion battery degradation: what you need to know",
        "publisher": "Physical Chemistry Chemical Physics",
        "url": "https://doi.org/10.1039/D1CP00359C",
        "type": "Review article",
        "scope": "Degradation mechanisms, modes, operational effects and their interactions.",
        "year": 2021,
        "accessed": "2026-10-27"
      }
    }
  ]
}