{
  "node": {
    "id": "term:aging-mechanism",
    "type": "Term",
    "label": "Aging mechanism",
    "properties": {
      "id": "aging-mechanism",
      "name": "Aging mechanism",
      "aka": [
        "degradation mode"
      ],
      "section": "topic-aging",
      "definition": "A specific physical or chemical process that degrades a cell — SEI growth, lithium plating, particle cracking, transition-metal dissolution. Mechanisms are grouped into three modes: loss of lithium inventory, loss of active material and resistance increase.",
      "related": [
        "loss-of-lithium-inventory",
        "loss-of-active-material",
        "impedance-rise",
        "aging"
      ],
      "lesson": "fundamentals/battery-aging/#where",
      "url": "https://lemonergy.com/learn/glossary/aging-mechanism/",
      "mentions": [
        "active-material",
        "sei",
        "lithium-plating",
        "particle-cracking",
        "transition-metal-dissolution"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:1354",
      "source": "term:aging-mechanism",
      "target": "topic:topic-aging",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:1355",
      "source": "term:aging-mechanism",
      "target": "term:loss-of-lithium-inventory",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1356",
      "source": "term:aging-mechanism",
      "target": "term:loss-of-active-material",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1357",
      "source": "term:aging-mechanism",
      "target": "term:impedance-rise",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1358",
      "source": "term:aging-mechanism",
      "target": "term:aging",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/aging-mechanism/active-material",
      "source": "term:aging-mechanism",
      "target": "term:active-material",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/aging-mechanism/sei",
      "source": "term:aging-mechanism",
      "target": "term:sei",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/aging-mechanism/lithium-plating",
      "source": "term:aging-mechanism",
      "target": "term:lithium-plating",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/aging-mechanism/particle-cracking",
      "source": "term:aging-mechanism",
      "target": "term:particle-cracking",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/aging-mechanism/transition-metal-dissolution",
      "source": "term:aging-mechanism",
      "target": "term:transition-metal-dissolution",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:1364",
      "source": "term:aging-mechanism",
      "target": "lesson:fundamentals/battery-aging/",
      "type": "explainedIn",
      "properties": {
        "sourceFile": "terms.json",
        "url": "https://lemonergy.com/learn/fundamentals/battery-aging/#where"
      }
    },
    {
      "id": "edge:1365",
      "source": "term:aging-mechanism",
      "target": "reference:edge-degradation",
      "type": "cites",
      "properties": {
        "sourceFile": "wiki-references.json",
        "scope": "direct technical reference"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-aging",
      "type": "Topic",
      "label": "Aging and degradation",
      "properties": {
        "id": "topic-aging",
        "name": "Aging and degradation",
        "lede": "Why a cell loses capacity and gains resistance, and the mechanisms behind it.",
        "context": "Separate mechanisms, observations and fitted models.",
        "example": "Capacity loss and resistance rise can have different causes; a film-growth curve cannot identify both.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-aging/",
        "lesson_label": "Open aging"
      }
    },
    {
      "id": "term:loss-of-lithium-inventory",
      "type": "Term",
      "label": "Loss of lithium inventory",
      "properties": {
        "id": "loss-of-lithium-inventory",
        "name": "Loss of lithium inventory",
        "abbr": "LLI",
        "section": "topic-aging",
        "definition": "The degradation mode in which cyclable lithium is consumed by side reactions — SEI growth, plating, electrolyte decomposition — and can no longer shuttle between the electrodes. It is the dominant cause of capacity fade in most lithium-ion cells.",
        "related": [
          "sei",
          "lithium-plating",
          "capacity-fade",
          "loss-of-active-material",
          "coulombic-efficiency"
        ],
        "url": "https://lemonergy.com/learn/glossary/loss-of-lithium-inventory/",
        "mentions": [
          "electrolyte",
          "aging-mechanism",
          "electrolyte-decomposition"
        ]
      }
    },
    {
      "id": "term:loss-of-active-material",
      "type": "Term",
      "label": "Loss of active material",
      "properties": {
        "id": "loss-of-active-material",
        "name": "Loss of active material",
        "abbr": "LAM",
        "section": "topic-aging",
        "definition": "The degradation mode in which electrode material becomes unable to store lithium: particles crack and lose electronic contact, structures collapse, or transition metals dissolve. It is tracked separately for each electrode.",
        "related": [
          "particle-cracking",
          "transition-metal-dissolution",
          "loss-of-lithium-inventory",
          "capacity-fade"
        ],
        "url": "https://lemonergy.com/learn/glossary/loss-of-active-material/",
        "mentions": [
          "electrode",
          "aging-mechanism"
        ]
      }
    },
    {
      "id": "term:impedance-rise",
      "type": "Term",
      "label": "Impedance rise",
      "properties": {
        "id": "impedance-rise",
        "name": "Impedance rise",
        "aka": [
          "resistance growth",
          "power fade"
        ],
        "section": "topic-aging",
        "definition": "An increase in a cell’s internal resistance as it ages. It costs voltage under load and therefore power, even while the stored charge is still there.",
        "related": [
          "internal-resistance",
          "sei",
          "cei",
          "state-of-power",
          "state-of-health"
        ],
        "lesson": "fundamentals/battery-aging/#crystals",
        "url": "https://lemonergy.com/learn/glossary/impedance-rise/",
        "mentions": [
          "closed-circuit-voltage"
        ]
      }
    },
    {
      "id": "term:aging",
      "type": "Term",
      "label": "Aging",
      "properties": {
        "id": "aging",
        "name": "Aging",
        "aka": [
          "degradation"
        ],
        "section": "topic-aging",
        "definition": "The gradual, irreversible change in a cell’s capacity, resistance and safety margins over time and use. It is the sum of many chemical and mechanical mechanisms, each driven by temperature, state of charge, current and cycle depth.",
        "related": [
          "calendar-aging",
          "cycle-aging",
          "capacity-fade",
          "impedance-rise",
          "aging-mechanism"
        ],
        "lesson": "fundamentals/battery-aging/#chain",
        "url": "https://lemonergy.com/learn/glossary/aging/",
        "mentions": [
          "state-of-charge"
        ]
      }
    },
    {
      "id": "term:active-material",
      "type": "Term",
      "label": "Active material",
      "properties": {
        "id": "active-material",
        "name": "Active material",
        "abbr": "AM",
        "section": "topic-components",
        "definition": "The part of an electrode that actually stores lithium — graphite on the negative side, an oxide or phosphate on the positive. It makes up most of the electrode coating; the rest is binder and conductive additive.",
        "related": [
          "cathode-active-material",
          "anode-active-material",
          "binder",
          "conductive-additive",
          "specific-capacity"
        ],
        "lesson": "fundamentals/cell-architecture/#composite",
        "example": {
          "title": "Choose a mass basis",
          "text": "A 100 g coating containing 95 g active material has different specific-capacity numbers when normalized to active mass versus total coating mass."
        },
        "url": "https://lemonergy.com/learn/glossary/active-material/",
        "mentions": [
          "electrode",
          "graphite",
          "coating"
        ]
      }
    },
    {
      "id": "term:sei",
      "type": "Term",
      "label": "Solid–electrolyte interphase",
      "properties": {
        "id": "sei",
        "name": "Solid–electrolyte interphase",
        "abbr": "SEI",
        "section": "topic-aging",
        "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.",
        "related": [
          "passivation",
          "formation",
          "calendar-aging",
          "loss-of-lithium-inventory",
          "cei"
        ],
        "lesson": "fundamentals/battery-aging/#sei",
        "url": "https://lemonergy.com/learn/glossary/sei/",
        "mentions": [
          "electrode",
          "graphite",
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:lithium-plating",
      "type": "Term",
      "label": "Lithium plating",
      "properties": {
        "id": "lithium-plating",
        "name": "Lithium plating",
        "section": "topic-aging",
        "definition": "Lithium metal depositing on the negative-electrode surface instead of intercalating into it. It is promoted by charging at low temperature or high current.",
        "related": [
          "dendrite",
          "fast-charging",
          "intercalation",
          "np-ratio",
          "dead-lithium",
          "electrodeposition"
        ],
        "lesson": "fundamentals/battery-aging/#plating",
        "url": "https://lemonergy.com/learn/glossary/lithium-plating/",
        "mentions": []
      }
    },
    {
      "id": "term:particle-cracking",
      "type": "Term",
      "label": "Particle cracking",
      "properties": {
        "id": "particle-cracking",
        "name": "Particle cracking",
        "section": "topic-aging",
        "definition": "Fracture of active-material particles from the volume change of repeated lithium insertion and removal. New surfaces consume electrolyte to form fresh SEI, and fragments that lose contact no longer store lithium.",
        "related": [
          "cycle-aging",
          "loss-of-active-material",
          "silicon-anode",
          "single-crystal",
          "depth-of-discharge"
        ],
        "lesson": "fundamentals/battery-aging/#cracking",
        "url": "https://lemonergy.com/learn/glossary/particle-cracking/",
        "mentions": [
          "electrolyte",
          "sei"
        ]
      }
    },
    {
      "id": "term:transition-metal-dissolution",
      "type": "Term",
      "label": "Transition-metal dissolution",
      "properties": {
        "id": "transition-metal-dissolution",
        "name": "Transition-metal dissolution",
        "section": "topic-aging",
        "definition": "Manganese, nickel or cobalt ions leaching from the positive electrode into the electrolyte, especially at high voltage and temperature or when HF is present. They migrate to the negative electrode and poison the SEI there, accelerating lithium loss.",
        "related": [
          "lmo",
          "hydrofluoric-acid",
          "sei",
          "loss-of-active-material",
          "crosstalk"
        ],
        "lesson": "fundamentals/battery-aging/#crystals",
        "url": "https://lemonergy.com/learn/glossary/transition-metal-dissolution/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "positive-electrode",
          "electrolyte",
          "cobalt",
          "leaching",
          "manganese"
        ]
      }
    },
    {
      "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"
      }
    }
  ]
}