{
  "node": {
    "id": "term:iron-chromium-flow-battery",
    "type": "Term",
    "label": "Iron–chromium flow battery",
    "properties": {
      "id": "iron-chromium-flow-battery",
      "name": "Iron–chromium flow battery",
      "abbr": "ICFB",
      "aka": [
        "Fe–Cr flow battery"
      ],
      "section": "topic-other-chemistries",
      "definition": "The first modern redox flow battery, developed by NASA in the 1970s, using Fe³⁺/Fe²⁺ and Cr³⁺/Cr²⁺ couples dissolved in hydrochloric acid for about 1.2 V. Both metals are cheap, but ions cross the membrane and the chromium side evolves hydrogen, so cells run warm with catalysts and rebalancing; vanadium chemistry largely displaced it.",
      "related": [
        "flow-battery",
        "long-duration-storage",
        "redox-reaction",
        "stationary-storage",
        "hydrogen-bromine-flow-battery"
      ],
      "url": "https://lemonergy.com/learn/glossary/iron-chromium-flow-battery/",
      "mentions": []
    }
  },
  "edges": [
    {
      "id": "edge:6036",
      "source": "term:iron-chromium-flow-battery",
      "target": "topic:topic-other-chemistries",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:6037",
      "source": "term:iron-chromium-flow-battery",
      "target": "term:flow-battery",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6038",
      "source": "term:iron-chromium-flow-battery",
      "target": "term:long-duration-storage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6039",
      "source": "term:iron-chromium-flow-battery",
      "target": "term:redox-reaction",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6040",
      "source": "term:iron-chromium-flow-battery",
      "target": "term:stationary-storage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6041",
      "source": "term:iron-chromium-flow-battery",
      "target": "term:hydrogen-bromine-flow-battery",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-other-chemistries",
      "type": "Topic",
      "label": "Other and emerging chemistries",
      "properties": {
        "id": "topic-other-chemistries",
        "name": "Other and emerging chemistries",
        "lede": "Batteries beyond today’s lithium-ion: lead, nickel and primary cells, flow and metal–air batteries, solid-state and lithium-metal cells, and the multivalent and sodium chemistries in development.",
        "context": "Do not carry lithium-ion assumptions into every chemistry.",
        "example": "Two chemistries can meet the same energy target with different voltage windows and charge termination.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-anatomy/",
        "lesson_label": "Open cell anatomy"
      }
    },
    {
      "id": "term:flow-battery",
      "type": "Term",
      "label": "Flow battery",
      "properties": {
        "id": "flow-battery",
        "name": "Flow battery",
        "aka": [
          "vanadium redox flow battery",
          "VRFB"
        ],
        "section": "topic-other-chemistries",
        "definition": "A battery whose energy is stored in liquid electrolytes held in external tanks and pumped through a reaction stack. Energy and power scale independently, which suits long-duration grid storage; vanadium is the most developed chemistry.",
        "related": [
          "stationary-storage",
          "long-duration-storage",
          "redox-reaction",
          "fuel-cell"
        ],
        "url": "https://lemonergy.com/learn/glossary/flow-battery/",
        "mentions": []
      }
    },
    {
      "id": "term:long-duration-storage",
      "type": "Term",
      "label": "Long-duration energy storage",
      "properties": {
        "id": "long-duration-storage",
        "name": "Long-duration energy storage",
        "abbr": "LDES",
        "section": "topic-applications",
        "definition": "Storage that discharges for eight hours or more, filling gaps that lithium-ion’s one-to-four-hour systems leave. Flow, iron–air and thermal technologies compete for it by making energy capacity cheap even when power is not.",
        "related": [
          "stationary-storage",
          "flow-battery",
          "e-rate",
          "levelized-cost-of-storage"
        ],
        "url": "https://lemonergy.com/learn/glossary/long-duration-storage/",
        "mentions": []
      }
    },
    {
      "id": "term:redox-reaction",
      "type": "Term",
      "label": "Redox reaction",
      "properties": {
        "id": "redox-reaction",
        "name": "Redox reaction",
        "section": "topic-electrochemistry",
        "definition": "A reaction in which electrons move from one species to another: one is oxidised, the other reduced. A battery separates the two halves onto two electrodes so the electrons must travel through the external circuit.",
        "related": [
          "oxidation",
          "reduction",
          "half-reaction",
          "electrode-potential",
          "galvanic-cell"
        ],
        "lesson": "labs/battery-materials-lab/#bml-aqueous-mechanism",
        "url": "https://lemonergy.com/learn/glossary/redox-reaction/",
        "mentions": []
      }
    },
    {
      "id": "term:stationary-storage",
      "type": "Term",
      "label": "Stationary storage",
      "properties": {
        "id": "stationary-storage",
        "name": "Stationary storage",
        "abbr": "BESS",
        "aka": [
          "battery energy storage system",
          "ESS"
        ],
        "section": "topic-applications",
        "definition": "Batteries installed in a fixed place — a container at a solar farm, a cabinet in a home — to shift energy in time or support the grid. LFP cells dominate because cost per cycle and safety matter more than mass.",
        "related": [
          "lfp",
          "energy-management-system",
          "inverter",
          "energy-arbitrage",
          "long-duration-storage",
          "ul-9540a"
        ],
        "url": "https://lemonergy.com/learn/glossary/stationary-storage/",
        "mentions": []
      }
    },
    {
      "id": "term:hydrogen-bromine-flow-battery",
      "type": "Term",
      "label": "Hydrogen–bromine flow battery",
      "properties": {
        "id": "hydrogen-bromine-flow-battery",
        "name": "Hydrogen–bromine flow battery",
        "abbr": "H₂–Br₂",
        "aka": [
          "HBr flow battery",
          "H2-Br2 flow battery"
        ],
        "section": "topic-other-chemistries",
        "definition": "A hybrid flow battery pairing a hydrogen gas electrode, built like a fuel cell’s, with a liquid bromine–bromide electrode, for about 1.1 V. Fast kinetics on both sides give very high power density and hydrobromic acid is cheap; the obstacles are corrosive, toxic bromine attacking the platinum catalyst and membrane, and storing the hydrogen.",
        "related": [
          "flow-battery",
          "fuel-cell",
          "zinc-bromine",
          "iron-chromium-flow-battery",
          "specific-power"
        ],
        "url": "https://lemonergy.com/learn/glossary/hydrogen-bromine-flow-battery/",
        "mentions": [
          "electrode"
        ]
      }
    }
  ]
}