{
  "node": {
    "id": "term:copper-foil",
    "type": "Term",
    "label": "Copper foil",
    "properties": {
      "id": "copper-foil",
      "name": "Copper foil",
      "section": "topic-components",
      "definition": "The negative current collector, typically 6–10 µm thick. Copper is used because it is stable at the low potential of a graphite electrode, where aluminium would alloy with lithium.",
      "related": [
        "current-collector",
        "aluminium-foil",
        "over-discharge",
        "copper-dissolution"
      ],
      "example": {
        "title": "Count collector mass",
        "text": "At equal area and density, doubling foil thickness doubles foil mass. Active-material-only capacity omits that mass change."
      },
      "url": "https://lemonergy.com/learn/glossary/copper-foil/",
      "mentions": [
        "electrode",
        "graphite"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:454",
      "source": "term:copper-foil",
      "target": "topic:topic-components",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:455",
      "source": "term:copper-foil",
      "target": "term:current-collector",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:456",
      "source": "term:copper-foil",
      "target": "term:aluminium-foil",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:457",
      "source": "term:copper-foil",
      "target": "term:over-discharge",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:458",
      "source": "term:copper-foil",
      "target": "term:copper-dissolution",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/copper-foil/electrode",
      "source": "term:copper-foil",
      "target": "term:electrode",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/copper-foil/graphite",
      "source": "term:copper-foil",
      "target": "term:graphite",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:461",
      "source": "term:copper-foil",
      "target": "reference:liu-manufacturing",
      "type": "cites",
      "properties": {
        "sourceFile": "wiki-references.json",
        "scope": "direct technical reference"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-components",
      "type": "Topic",
      "label": "Cell components and electrode materials",
      "properties": {
        "id": "topic-components",
        "name": "Cell components and electrode materials",
        "lede": "What a cell is physically made of — active materials, binders, additives, foils and tabs — and how its electrodes are put together.",
        "context": "Connect each material with its function.",
        "example": "Electrons travel through additive, foil and tab; ions use electrolyte and separator pathways.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-anatomy/",
        "lesson_label": "Open cell anatomy"
      }
    },
    {
      "id": "term:current-collector",
      "type": "Term",
      "label": "Current collector",
      "properties": {
        "id": "current-collector",
        "name": "Current collector",
        "section": "topic-components",
        "definition": "The thin metal foil that carries electrons between an electrode and the external circuit — usually copper on the negative side and aluminium on the positive side.",
        "related": [
          "copper-foil",
          "aluminium-foil",
          "tab",
          "electronic-path"
        ],
        "lesson": "fundamentals/cell-anatomy/#components",
        "example": {
          "title": "Follow current to a tab",
          "text": "Current converges through foil toward the tab. The collector contributes mass and resistance without being the principal active material."
        },
        "url": "https://lemonergy.com/learn/glossary/current-collector/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "id": "term:aluminium-foil",
      "type": "Term",
      "label": "Aluminium foil",
      "properties": {
        "id": "aluminium-foil",
        "name": "Aluminium foil",
        "section": "topic-components",
        "definition": "The positive current collector, typically 10–15 µm thick. A thin passive film keeps it stable at the high potential of the positive electrode, where copper would corrode.",
        "related": [
          "current-collector",
          "copper-foil",
          "passivation"
        ],
        "example": {
          "title": "Keep normalization consistent",
          "text": "Active-material capacity can remain unchanged while a heavier foil lowers a finished electrode’s capacity per unit total mass."
        },
        "url": "https://lemonergy.com/learn/glossary/aluminium-foil/",
        "mentions": [
          "electrode",
          "positive-electrode"
        ]
      }
    },
    {
      "id": "term:over-discharge",
      "type": "Term",
      "label": "Over-discharge",
      "properties": {
        "id": "over-discharge",
        "name": "Over-discharge",
        "aka": [
          "deep discharge"
        ],
        "section": "topic-charging",
        "definition": "Discharging below the lower cutoff voltage. Near 1.5 V the copper current collector begins to dissolve, and on the next charge it can redeposit as metal that shorts the cell, so a deeply discharged cell should not simply be recharged.",
        "related": [
          "cutoff-voltage",
          "copper-dissolution",
          "internal-short-circuit",
          "bms",
          "low-voltage-disconnect"
        ],
        "url": "https://lemonergy.com/learn/glossary/over-discharge/",
        "mentions": [
          "current-collector"
        ]
      }
    },
    {
      "id": "term:copper-dissolution",
      "type": "Term",
      "label": "Copper dissolution",
      "properties": {
        "id": "copper-dissolution",
        "name": "Copper dissolution",
        "section": "topic-aging",
        "definition": "Oxidation of the copper current collector when a cell is over-discharged and the negative electrode’s potential rises too high. Dissolved copper redeposits on recharge as metallic filaments that can short the separator, which is why over-discharged cells are not simply recharged.",
        "related": [
          "over-discharge",
          "copper-foil",
          "internal-short-circuit",
          "current-collector-corrosion"
        ],
        "url": "https://lemonergy.com/learn/glossary/copper-dissolution/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "current-collector",
          "separator",
          "oxidation"
        ]
      }
    },
    {
      "id": "term:electrode",
      "type": "Term",
      "label": "Electrode",
      "properties": {
        "id": "electrode",
        "name": "Electrode",
        "section": "topic-components",
        "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.",
        "related": [
          "negative-electrode",
          "positive-electrode",
          "porous-electrode",
          "current-collector"
        ],
        "lesson": "fundamentals/cell-anatomy/#components",
        "example": {
          "title": "Two transport paths",
          "text": "Electrons need connected solid paths to the collector; ions need electrolyte paths to reaction sites. More of one constituent displaces others at fixed volume."
        },
        "url": "https://lemonergy.com/learn/glossary/electrode/",
        "mentions": [
          "electrolyte",
          "coating"
        ]
      }
    },
    {
      "id": "term:graphite",
      "type": "Term",
      "label": "Graphite",
      "properties": {
        "id": "graphite",
        "name": "Graphite",
        "section": "topic-components",
        "definition": "Layered carbon, the negative active material of nearly all lithium-ion cells. Lithium intercalates between its layers up to LiC₆, a theoretical 372 mAh/g, at a potential about 0.1 V above lithium metal.",
        "related": [
          "anode-active-material",
          "intercalation",
          "natural-graphite",
          "synthetic-graphite",
          "lithium-plating"
        ],
        "lesson": "fundamentals/cell-anatomy/#components",
        "example": {
          "title": "Compare matching mass bases",
          "text": "A graphite value per gram of active material cannot be directly compared with a value including binder, additive and foil."
        },
        "url": "https://lemonergy.com/learn/glossary/graphite/",
        "mentions": [
          "milliampere-hour",
          "active-material"
        ]
      }
    },
    {
      "id": "reference:liu-manufacturing",
      "type": "Reference",
      "label": "Current and future lithium-ion battery manufacturing",
      "properties": {
        "title": "Current and future lithium-ion battery manufacturing",
        "publisher": "iScience",
        "url": "https://doi.org/10.1016/j.isci.2021.102332",
        "type": "Review article",
        "scope": "Electrode preparation, cell assembly, formation and manufacturing trade-offs.",
        "year": 2021,
        "authors": [
          "Yangtao Liu",
          "Ruihan Zhang",
          "Jun Wang",
          "Yan Wang"
        ],
        "accessed": "2026-10-27"
      }
    }
  ]
}