{
  "node": {
    "id": "term:concentration-polarization",
    "type": "Term",
    "label": "Concentration polarization",
    "properties": {
      "id": "concentration-polarization",
      "name": "Concentration polarization",
      "section": "topic-electrochemistry",
      "definition": "Voltage loss that arises when reactant is consumed faster than diffusion can replace it, so the concentration at the surface differs from the bulk. It dominates at high current and low temperature and recovers slowly when current stops.",
      "related": [
        "polarization",
        "diffusion",
        "overpotential",
        "relaxation",
        "concentration-gradient"
      ],
      "url": "https://lemonergy.com/learn/glossary/concentration-polarization/",
      "mentions": []
    }
  },
  "edges": [
    {
      "id": "edge:1936",
      "source": "term:concentration-polarization",
      "target": "topic:topic-electrochemistry",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:1937",
      "source": "term:concentration-polarization",
      "target": "term:polarization",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1938",
      "source": "term:concentration-polarization",
      "target": "term:diffusion",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1939",
      "source": "term:concentration-polarization",
      "target": "term:overpotential",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1940",
      "source": "term:concentration-polarization",
      "target": "term:relaxation",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1941",
      "source": "term:concentration-polarization",
      "target": "term:concentration-gradient",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-electrochemistry",
      "type": "Topic",
      "label": "Electrochemistry fundamentals",
      "properties": {
        "id": "topic-electrochemistry",
        "name": "Electrochemistry fundamentals",
        "lede": "The reactions and potentials that make a cell a battery.",
        "context": "Connect reaction sites and transport paths.",
        "example": "A circuit can predict terminal voltage while leaving electrode potentials and reaction kinetics unresolved.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-anatomy/",
        "lesson_label": "Open cell anatomy"
      }
    },
    {
      "id": "term:polarization",
      "type": "Term",
      "label": "Polarization",
      "properties": {
        "id": "polarization",
        "name": "Polarization",
        "aka": [
          "overvoltage"
        ],
        "section": "topic-charging",
        "definition": "The gap between a cell’s terminal voltage under load and its open-circuit voltage. It has ohmic, charge-transfer and concentration parts, grows with current and falling temperature, and is where delivered energy is lost.",
        "unit": "V",
        "related": [
          "overpotential",
          "ir-drop",
          "concentration-polarization",
          "open-circuit-voltage",
          "polarisation-curve"
        ],
        "url": "https://lemonergy.com/learn/glossary/polarization/",
        "mentions": [
          "voltage",
          "closed-circuit-voltage"
        ]
      }
    },
    {
      "id": "term:diffusion",
      "type": "Term",
      "label": "Diffusion",
      "properties": {
        "id": "diffusion",
        "name": "Diffusion",
        "section": "topic-transport",
        "definition": "The net movement of a species from where it is concentrated to where it is scarce, driven by random thermal motion. In a cell lithium diffuses through the electrolyte in the pores and, far more slowly, through the solid particles themselves.",
        "related": [
          "ficks-first-law",
          "diffusion-coefficient",
          "solid-state-diffusion",
          "concentration-gradient",
          "migration"
        ],
        "lesson": "transport/ficks-first-law/#in-a-cell",
        "url": "https://lemonergy.com/learn/glossary/diffusion/",
        "mentions": [
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:overpotential",
      "type": "Term",
      "label": "Overpotential",
      "properties": {
        "id": "overpotential",
        "name": "Overpotential",
        "abbr": "η",
        "section": "topic-electrochemistry",
        "definition": "The extra voltage, beyond the equilibrium potential, needed to drive a reaction at a given rate at one electrode. Activation overpotential pays for charge transfer, concentration overpotential for depleted reactant, and both appear as polarization at the terminals.",
        "unit": "V",
        "related": [
          "polarization",
          "butler-volmer",
          "exchange-current-density",
          "concentration-polarization"
        ],
        "url": "https://lemonergy.com/learn/glossary/overpotential/",
        "mentions": [
          "electrode",
          "charge-transfer"
        ]
      }
    },
    {
      "id": "term:relaxation",
      "type": "Term",
      "label": "Relaxation",
      "properties": {
        "id": "relaxation",
        "name": "Relaxation",
        "aka": [
          "rest"
        ],
        "section": "topic-charging",
        "definition": "The slow recovery of a cell’s voltage towards open-circuit voltage after current stops, as concentration gradients inside the electrodes level out. It takes minutes to hours, which is why OCV measurements need a rest period.",
        "related": [
          "open-circuit-voltage",
          "polarization",
          "diffusion",
          "hppc",
          "voltage-relaxation-analysis"
        ],
        "url": "https://lemonergy.com/learn/glossary/relaxation/",
        "mentions": []
      }
    },
    {
      "id": "term:concentration-gradient",
      "type": "Term",
      "label": "Concentration gradient",
      "properties": {
        "id": "concentration-gradient",
        "name": "Concentration gradient",
        "section": "topic-transport",
        "definition": "The rate at which concentration changes with distance, dc/dx, in mol/m⁴. It is the driving force in Fick’s law; current creates one across the electrolyte and inside each particle, and it relaxes away when current stops.",
        "unit": "mol/m⁴",
        "related": [
          "ficks-first-law",
          "concentration-polarization",
          "relaxation",
          "diffusion"
        ],
        "lesson": "transport/ficks-first-law/#sign",
        "url": "https://lemonergy.com/learn/glossary/concentration-gradient/",
        "mentions": [
          "electrolyte"
        ]
      }
    }
  ]
}