{
  "node": {
    "id": "term:x-ray-computed-tomography",
    "type": "Term",
    "label": "X-ray computed tomography",
    "properties": {
      "id": "x-ray-computed-tomography",
      "name": "X-ray computed tomography",
      "abbr": "CT",
      "aka": [
        "X-ray CT",
        "micro-CT",
        "nano-CT",
        "CT scan"
      ],
      "section": "topic-analysis",
      "definition": "Taking X-ray images of an object from hundreds of angles and reconstructing them into a 3D volume, without opening it. On whole cells it reveals jelly-roll deformation, electrode overhang, weld defects and foreign particles; at higher resolution it maps electrode porosity, and fast synchrotron CT has filmed thermal runaway as it happens.",
      "related": [
        "post-mortem",
        "jelly-roll",
        "focused-ion-beam-sem",
        "porosity",
        "thermal-runaway"
      ],
      "url": "https://lemonergy.com/learn/glossary/x-ray-computed-tomography/",
      "mentions": [
        "electrode",
        "metal-particle-contamination",
        "electrode-wrinkling"
      ]
    }
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    {
      "id": "edge:5632",
      "source": "term:x-ray-computed-tomography",
      "target": "term:post-mortem",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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    {
      "id": "edge:5633",
      "source": "term:x-ray-computed-tomography",
      "target": "term:jelly-roll",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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      "id": "edge:5634",
      "source": "term:x-ray-computed-tomography",
      "target": "term:focused-ion-beam-sem",
      "type": "relatedTo",
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        "meaning": "Related context; not a causal claim"
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      "id": "edge:5635",
      "source": "term:x-ray-computed-tomography",
      "target": "term:porosity",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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    },
    {
      "id": "edge:5636",
      "source": "term:x-ray-computed-tomography",
      "target": "term:thermal-runaway",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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    {
      "id": "edge:mentions/x-ray-computed-tomography/electrode",
      "source": "term:x-ray-computed-tomography",
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      "source": "term:x-ray-computed-tomography",
      "target": "term:metal-particle-contamination",
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      "id": "topic:topic-analysis",
      "type": "Topic",
      "label": "Materials analysis and post-mortem",
      "properties": {
        "id": "topic-analysis",
        "name": "Materials analysis and post-mortem",
        "lede": "The laboratory techniques that look inside electrodes, interphases and electrolytes to see what a cell is made of and how it aged.",
        "context": "Connect results with scale and specimen preparation.",
        "example": "Surface and bulk measurements may find different compositions in the same electrode without contradiction.",
        "lesson_url": "https://lemonergy.com/learn/labs/battery-materials-lab/",
        "lesson_label": "Open materials lab"
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    {
      "id": "term:post-mortem",
      "type": "Term",
      "label": "Post-mortem analysis",
      "properties": {
        "id": "post-mortem",
        "name": "Post-mortem analysis",
        "aka": [
          "teardown"
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        "section": "topic-analysis",
        "definition": "Opening an aged or failed cell in an inert glovebox and examining its electrodes by microscopy, diffraction and chemical analysis. It confirms which degradation mechanisms actually occurred rather than inferring them from voltage.",
        "related": [
          "aging-mechanism",
          "scanning-electron-microscopy",
          "x-ray-diffraction",
          "differential-voltage-analysis",
          "nuclear-magnetic-resonance"
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        "url": "https://lemonergy.com/learn/glossary/post-mortem/",
        "mentions": []
      }
    },
    {
      "id": "term:jelly-roll",
      "type": "Term",
      "label": "Jelly roll",
      "properties": {
        "id": "jelly-roll",
        "name": "Jelly roll",
        "section": "topic-components",
        "definition": "Electrodes and separators wound together into a spiral. It is the inside of a cylindrical cell and of many prismatic cells; large pouch cells usually use stacked sheets instead.",
        "related": [
          "winding",
          "cylindrical-cell",
          "prismatic-cell",
          "stacking"
        ],
        "lesson": "fundamentals/cell-architecture/#whole-cell",
        "example": {
          "title": "Unroll the geometry",
          "text": "A wound assembly contains long electrode and separator strips; the cylindrical exterior does not make its electrodes solid cylinders."
        },
        "url": "https://lemonergy.com/learn/glossary/jelly-roll/",
        "mentions": []
      }
    },
    {
      "id": "term:focused-ion-beam-sem",
      "type": "Term",
      "label": "Focused ion beam SEM",
      "properties": {
        "id": "focused-ion-beam-sem",
        "name": "Focused ion beam SEM",
        "abbr": "FIB-SEM",
        "aka": [
          "focused ion beam",
          "FIB",
          "plasma FIB",
          "serial sectioning"
        ],
        "section": "topic-analysis",
        "definition": "A scanning electron microscope paired with an ion beam that mills material away at a chosen spot. It cuts clean cross-sections through particles and coatings, lifts out thin slices for TEM, and by alternately milling and imaging rebuilds an electrode’s microstructure in 3D for porosity and tortuosity.",
        "related": [
          "scanning-electron-microscopy",
          "transmission-electron-microscopy",
          "porosity",
          "tortuosity",
          "x-ray-computed-tomography"
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        "url": "https://lemonergy.com/learn/glossary/focused-ion-beam-sem/",
        "mentions": [
          "electrode"
        ]
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    },
    {
      "id": "term:porosity",
      "type": "Term",
      "label": "Porosity",
      "properties": {
        "id": "porosity",
        "name": "Porosity",
        "abbr": "ε",
        "section": "topic-components",
        "definition": "The fraction of a layer’s volume that is empty space. In a lithium-ion electrode the pores — roughly 20–35 % of the volume after calendering — are filled with electrolyte, which carries ions to the particles.",
        "unit": "—",
        "related": [
          "porous-electrode",
          "tortuosity",
          "calendering",
          "bruggeman-relation"
        ],
        "lesson": "fundamentals/cell-architecture/#porosity",
        "example": {
          "title": "Use the volume basis",
          "text": "Pore volume of 0.3 cm³ within 1 cm³ total electrode volume means 30% porosity. It does not specify connectivity or tortuosity."
        },
        "url": "https://lemonergy.com/learn/glossary/porosity/",
        "mentions": [
          "electrode",
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:thermal-runaway",
      "type": "Term",
      "label": "Thermal runaway",
      "properties": {
        "id": "thermal-runaway",
        "name": "Thermal runaway",
        "section": "topic-safety",
        "definition": "Self-accelerating heating in a cell: heat speeds up reactions that release more heat, until the cell vents, catches fire or ruptures. An internal short, overcharge or external heating can trigger it.",
        "related": [
          "onset-temperature",
          "thermal-propagation",
          "venting",
          "separator-shutdown",
          "thermal-runaway-energy",
          "exothermic"
        ],
        "lesson": "fundamentals/cell-anatomy/#short-circuit",
        "url": "https://lemonergy.com/learn/glossary/thermal-runaway/",
        "mentions": [
          "overcharge"
        ]
      }
    },
    {
      "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:metal-particle-contamination",
      "type": "Term",
      "label": "Metal particle contamination",
      "properties": {
        "id": "metal-particle-contamination",
        "name": "Metal particle contamination",
        "aka": [
          "metal particle",
          "metallic contamination",
          "foreign particles"
        ],
        "section": "topic-manufacturing",
        "definition": "Stray fragments of iron, copper, zinc or steel from raw materials, worn equipment or cutting. A particle tens of micrometres across can pierce the separator, or dissolve and regrow across it, causing high self-discharge or a latent internal short circuit — the cause of the 2006 laptop battery recalls. Magnetic filters, cleanroom discipline and K-value screening keep them out.",
        "related": [
          "internal-short-circuit",
          "cleanroom",
          "k-value",
          "self-discharge",
          "burr"
        ],
        "url": "https://lemonergy.com/learn/glossary/metal-particle-contamination/",
        "mentions": [
          "separator",
          "short-circuit"
        ]
      }
    },
    {
      "id": "term:electrode-wrinkling",
      "type": "Term",
      "label": "Electrode wrinkling and buckling",
      "properties": {
        "id": "electrode-wrinkling",
        "name": "Electrode wrinkling and buckling",
        "aka": [
          "wrinkling",
          "buckling",
          "foil wrinkles",
          "jelly-roll deformation"
        ],
        "section": "topic-manufacturing",
        "definition": "Out-of-plane waves or folds in an electrode. In production they come from calendering, where the coated area stretches more than the bare foil edge, and from uneven web tension in winding; in service, electrode expansion can buckle a tightly wound jelly roll. Wrinkles leave uneven gaps and pressure that cause local lithium plating or separator damage.",
        "related": [
          "calendering",
          "winding",
          "jelly-roll",
          "lithium-plating",
          "swelling"
        ],
        "url": "https://lemonergy.com/learn/glossary/electrode-wrinkling/",
        "mentions": [
          "electrode",
          "separator"
        ]
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    }
  ]
}