{
  "node": {
    "id": "term:tap-density",
    "type": "Term",
    "label": "Tap density",
    "properties": {
      "id": "tap-density",
      "name": "Tap density",
      "aka": [
        "tapped density"
      ],
      "section": "topic-components",
      "definition": "The bulk density of a powder after a cylinder of it has been mechanically tapped a set number of times, as in ASTM B527. Dense, spherical NMC reaches about 2.6–2.8 g/cm³, LFP only about 0.8–1.1 g/cm³; higher tap density lets calendering reach a higher electrode density and so more energy per litre.",
      "unit": "g/cm³",
      "related": [
        "electrode-density",
        "particle-size",
        "calendering",
        "energy-density",
        "cathode-active-material",
        "precursor"
      ],
      "url": "https://lemonergy.com/learn/glossary/tap-density/",
      "mentions": [
        "electrode"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:5713",
      "source": "term:tap-density",
      "target": "topic:topic-components",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:5714",
      "source": "term:tap-density",
      "target": "term:electrode-density",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5715",
      "source": "term:tap-density",
      "target": "term:particle-size",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5716",
      "source": "term:tap-density",
      "target": "term:calendering",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5717",
      "source": "term:tap-density",
      "target": "term:energy-density",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5718",
      "source": "term:tap-density",
      "target": "term:cathode-active-material",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5719",
      "source": "term:tap-density",
      "target": "term:precursor",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/tap-density/electrode",
      "source": "term:tap-density",
      "target": "term:electrode",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    }
  ],
  "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:electrode-density",
      "type": "Term",
      "label": "Electrode density",
      "properties": {
        "id": "electrode-density",
        "name": "Electrode density",
        "aka": [
          "press density"
        ],
        "section": "topic-manufacturing",
        "definition": "The mass of coating per unit volume after calendering, around 1.6 g/cm³ for graphite and 3.4–3.6 g/cm³ for NMC. Higher density raises energy density but lowers porosity and slows ion transport.",
        "unit": "g/cm³",
        "related": [
          "calendering",
          "porosity",
          "energy-density",
          "areal-loading",
          "tap-density"
        ],
        "url": "https://lemonergy.com/learn/glossary/electrode-density/",
        "mentions": [
          "graphite",
          "coating"
        ]
      }
    },
    {
      "id": "term:particle-size",
      "type": "Term",
      "label": "Particle size",
      "properties": {
        "id": "particle-size",
        "name": "Particle size",
        "aka": [
          "D50"
        ],
        "section": "topic-transport",
        "definition": "The diameter of active-material particles, usually quoted as D50, the median, in micrometres. Small particles shorten the solid diffusion path and favour power; large ones pack densely and favour energy and stability.",
        "unit": "µm",
        "related": [
          "solid-state-diffusion",
          "specific-surface-area",
          "rate-capability",
          "single-crystal"
        ],
        "url": "https://lemonergy.com/learn/glossary/particle-size/",
        "mentions": [
          "diffusion"
        ]
      }
    },
    {
      "id": "term:calendering",
      "type": "Term",
      "label": "Calendering",
      "properties": {
        "id": "calendering",
        "name": "Calendering",
        "section": "topic-manufacturing",
        "definition": "Compressing a dried electrode coating between rollers to set its thickness, density and porosity. It is one of the electrode-making steps in cell production.",
        "related": [
          "porosity",
          "electrode-density",
          "drying",
          "slitting"
        ],
        "lesson": "fundamentals/cell-production/#electrodes",
        "example": {
          "title": "Connect thickness and density",
          "text": "At fixed mass and area, reducing thickness raises bulk density. The pore structure still needs to support wetting and transport."
        },
        "url": "https://lemonergy.com/learn/glossary/calendering/",
        "mentions": [
          "electrode",
          "cell-production",
          "coating"
        ]
      }
    },
    {
      "id": "term:energy-density",
      "type": "Term",
      "label": "Energy density",
      "properties": {
        "id": "energy-density",
        "name": "Energy density",
        "aka": [
          "volumetric energy density"
        ],
        "section": "topic-ratings",
        "definition": "Stored energy per unit volume, in watt-hours per litre. It is the figure that matters when space is the constraint, as in a phone or under a car floor; high-energy cylindrical cells pass 700 Wh/L.",
        "unit": "Wh/L",
        "related": [
          "specific-energy",
          "nominal-energy",
          "ragone-plot",
          "areal-loading"
        ],
        "lesson": "fundamentals/capacity-and-c-rate/#energy",
        "url": "https://lemonergy.com/learn/glossary/energy-density/",
        "mentions": []
      }
    },
    {
      "id": "term:cathode-active-material",
      "type": "Term",
      "label": "Cathode active material",
      "properties": {
        "id": "cathode-active-material",
        "name": "Cathode active material",
        "abbr": "CAM",
        "section": "topic-components",
        "definition": "The lithium-containing compound in the positive electrode — NMC, NCA, LFP or LCO powder — that supplies the cell’s cyclable lithium. It is the most expensive material in most cells and sets the nominal voltage and much of the energy density.",
        "related": [
          "active-material",
          "nmc",
          "lfp",
          "precursor",
          "specific-capacity"
        ],
        "url": "https://lemonergy.com/learn/glossary/cathode-active-material/",
        "mentions": [
          "electrode",
          "positive-electrode",
          "nominal-voltage",
          "energy-density"
        ]
      }
    },
    {
      "id": "term:precursor",
      "type": "Term",
      "label": "Precursor cathode active material",
      "properties": {
        "id": "precursor",
        "name": "Precursor cathode active material",
        "abbr": "pCAM",
        "section": "topic-manufacturing",
        "definition": "The mixed nickel–manganese–cobalt hydroxide made by co-precipitation from metal sulfate solutions, before lithium is added. Its particle size and shape are set here and carried through to the finished NMC powder.",
        "related": [
          "cathode-active-material",
          "calcination",
          "nmc",
          "nickel-sulfate"
        ],
        "url": "https://lemonergy.com/learn/glossary/precursor/",
        "mentions": [
          "particle-size",
          "cobalt",
          "manganese"
        ]
      }
    },
    {
      "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"
        ]
      }
    }
  ]
}