{
  "node": {
    "id": "term:standard-potential",
    "type": "Term",
    "label": "Standard electrode potential",
    "properties": {
      "id": "standard-potential",
      "name": "Standard electrode potential",
      "abbr": "E°",
      "section": "topic-electrochemistry",
      "definition": "An electrode’s potential under standard conditions, tabulated against the standard hydrogen electrode. Lithium’s −3.04 V is the most negative of any metal, which is why lithium cells have the highest voltages.",
      "unit": "V",
      "related": [
        "electrode-potential",
        "nernst-equation",
        "cell-voltage"
      ],
      "url": "https://lemonergy.com/learn/glossary/standard-potential/",
      "mentions": [
        "electrode",
        "standard-hydrogen-electrode"
      ]
    }
  },
  "edges": [
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      "source": "term:standard-potential",
      "target": "topic:topic-electrochemistry",
      "type": "belongsTo",
      "properties": {
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    {
      "id": "edge:1846",
      "source": "term:standard-potential",
      "target": "term:electrode-potential",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:1847",
      "source": "term:standard-potential",
      "target": "term:nernst-equation",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
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    },
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      "id": "edge:1848",
      "source": "term:standard-potential",
      "target": "term:cell-voltage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
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      "source": "term:standard-potential",
      "target": "term:electrode",
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      "source": "term:standard-potential",
      "target": "reference:iupac-nernst",
      "type": "cites",
      "properties": {
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        "scope": "direct technical reference"
      }
    }
  ],
  "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:electrode-potential",
      "type": "Term",
      "label": "Electrode potential",
      "properties": {
        "id": "electrode-potential",
        "name": "Electrode potential",
        "section": "topic-electrochemistry",
        "definition": "The potential of an electrode relative to a reference, which for lithium-ion work is lithium metal in the same electrolyte, written as V vs Li/Li⁺. Graphite sits near 0.1 V and layered oxides near 3.7–4.3 V on this scale.",
        "unit": "V vs Li/Li⁺",
        "related": [
          "standard-potential",
          "cell-voltage",
          "reference-electrode",
          "half-reaction"
        ],
        "lesson": "labs/battery-materials-lab/#battery-materials-lab",
        "url": "https://lemonergy.com/learn/glossary/electrode-potential/",
        "mentions": [
          "electrode",
          "graphite",
          "electrolyte"
        ]
      }
    },
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      "id": "term:nernst-equation",
      "type": "Term",
      "label": "Nernst equation",
      "properties": {
        "id": "nernst-equation",
        "name": "Nernst equation",
        "section": "topic-electrochemistry",
        "definition": "The relation between an electrode’s potential and the concentrations, or activities, of the species in its half-reaction. It explains why open-circuit voltage changes with state of charge and temperature.",
        "formula": "E = E° − (RT/nF)·ln Q",
        "related": [
          "electrode-potential",
          "standard-potential",
          "open-circuit-voltage",
          "gibbs-free-energy"
        ],
        "example": {
          "title": "Change a reaction quotient by a decade",
          "text": "At 298.15 K with n = 1, increasing the dimensionless reaction quotient from 1 to 10 lowers E by about 59.2 mV. Use activities or a justified concentration approximation."
        },
        "url": "https://lemonergy.com/learn/glossary/nernst-equation/",
        "mentions": [
          "electrode",
          "state-of-charge",
          "half-reaction"
        ]
      }
    },
    {
      "id": "term:cell-voltage",
      "type": "Term",
      "label": "Cell voltage",
      "properties": {
        "id": "cell-voltage",
        "name": "Cell voltage",
        "aka": [
          "electromotive force",
          "EMF"
        ],
        "section": "topic-electrochemistry",
        "definition": "The difference between the positive and negative electrode potentials at equilibrium: for NMC against graphite about 3.7 V. It is set by the chemistry, and the difference in Gibbs free energy of the cell reaction per unit charge.",
        "formula": "E = E₊ − E₋ = −ΔG / nF",
        "unit": "V",
        "related": [
          "electrode-potential",
          "gibbs-free-energy",
          "open-circuit-voltage",
          "nominal-voltage"
        ],
        "example": {
          "title": "Subtract equilibrium electrode potentials",
          "text": "If two illustrative electrode potentials are 4.0 V and 0.2 V versus the same reference, their equilibrium cell voltage is 3.8 V. Under load, resistance and polarization change the measured terminal voltage."
        },
        "url": "https://lemonergy.com/learn/glossary/cell-voltage/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "graphite"
        ]
      }
    },
    {
      "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:standard-hydrogen-electrode",
      "type": "Term",
      "label": "Standard hydrogen electrode",
      "properties": {
        "id": "standard-hydrogen-electrode",
        "name": "Standard hydrogen electrode",
        "abbr": "SHE",
        "section": "topic-electrochemistry",
        "definition": "The reference electrode that defines zero on the electrochemical potential scale: platinum in a solution of unit hydrogen-ion activity, bubbled with hydrogen at 1 bar. Battery work mostly uses the Li/Li⁺ scale instead, which sits 3.04 V below it, so 4.2 V vs Li/Li⁺ is about 1.16 V vs SHE.",
        "formula": "E(vs SHE) ≈ E(vs Li/Li⁺) − 3.04 V",
        "unit": "V",
        "related": [
          "reference-electrode",
          "standard-potential",
          "electrode-potential",
          "half-reaction"
        ],
        "example": {
          "title": "Convert a reference potential",
          "text": "Using the approximate standard-state offset of −3.04 V for Li/Li⁺ versus SHE, an electrode at 4.0 V versus Li/Li⁺ is approximately 0.96 V versus SHE. Actual reference conditions and solvent conventions matter."
        },
        "url": "https://lemonergy.com/learn/glossary/standard-hydrogen-electrode/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "id": "reference:iupac-nernst",
      "type": "Reference",
      "label": "Nernst equation",
      "properties": {
        "title": "Nernst equation",
        "publisher": "IUPAC Gold Book",
        "url": "https://goldbook.iupac.org/terms/view/09068",
        "type": "Terminology reference",
        "scope": "Equilibrium potential as a function of activities; distinguishes activities from concentration approximations.",
        "year": 2025,
        "accessed": "2026-10-27"
      }
    }
  ]
}