{
  "node": {
    "id": "term:sodium-ion",
    "type": "Term",
    "label": "Sodium-ion battery",
    "properties": {
      "id": "sodium-ion",
      "name": "Sodium-ion battery",
      "abbr": "Na-ion",
      "section": "topic-other-chemistries",
      "definition": "A cell built like a lithium-ion cell but shuttling sodium ions, usually between a hard-carbon negative electrode and a layered oxide or Prussian-blue positive. It uses no lithium, cobalt or copper, at the cost of lower energy density.",
      "related": [
        "hard-carbon",
        "lithium-ion",
        "energy-density",
        "stationary-storage",
        "seawater-battery"
      ],
      "url": "https://lemonergy.com/learn/glossary/sodium-ion/",
      "mentions": [
        "electrode",
        "negative-electrode",
        "cobalt",
        "layered-oxide"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:729",
      "source": "term:sodium-ion",
      "target": "topic:topic-other-chemistries",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:730",
      "source": "term:sodium-ion",
      "target": "term:hard-carbon",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:731",
      "source": "term:sodium-ion",
      "target": "term:lithium-ion",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:732",
      "source": "term:sodium-ion",
      "target": "term:energy-density",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:733",
      "source": "term:sodium-ion",
      "target": "term:stationary-storage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:734",
      "source": "term:sodium-ion",
      "target": "term:seawater-battery",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/sodium-ion/electrode",
      "source": "term:sodium-ion",
      "target": "term:electrode",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/sodium-ion/negative-electrode",
      "source": "term:sodium-ion",
      "target": "term:negative-electrode",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/sodium-ion/cobalt",
      "source": "term:sodium-ion",
      "target": "term:cobalt",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/sodium-ion/layered-oxide",
      "source": "term:sodium-ion",
      "target": "term:layered-oxide",
      "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-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:hard-carbon",
      "type": "Term",
      "label": "Hard carbon",
      "properties": {
        "id": "hard-carbon",
        "name": "Hard carbon",
        "section": "topic-components",
        "definition": "A disordered, non-graphitisable carbon used as the negative electrode of sodium-ion cells, where graphite barely works, and as a fast-charge additive in lithium-ion. Its open structure accepts ions without the strict layer spacing of graphite.",
        "related": [
          "sodium-ion",
          "graphite",
          "anode-active-material"
        ],
        "url": "https://lemonergy.com/learn/glossary/hard-carbon/",
        "mentions": [
          "electrode",
          "negative-electrode"
        ]
      }
    },
    {
      "id": "term:lithium-ion",
      "type": "Term",
      "label": "Lithium-ion battery",
      "properties": {
        "id": "lithium-ion",
        "name": "Lithium-ion battery",
        "abbr": "Li-ion",
        "section": "topic-chemistries",
        "definition": "A rechargeable cell in which lithium ions shuttle between two intercalation electrodes, typically graphite and a lithium metal oxide, through a non-aqueous electrolyte. Commercialised in 1991, it dominates portable electronics, electric vehicles and new grid storage.",
        "related": [
          "intercalation",
          "graphite",
          "nmc",
          "lfp",
          "rocking-chair",
          "lithium"
        ],
        "lesson": "fundamentals/battery-basics/#how-it-works",
        "url": "https://lemonergy.com/learn/glossary/lithium-ion/",
        "mentions": [
          "electrolyte"
        ]
      }
    },
    {
      "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: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:seawater-battery",
      "type": "Term",
      "label": "Seawater battery",
      "properties": {
        "id": "seawater-battery",
        "name": "Seawater battery",
        "aka": [
          "seawater-activated battery",
          "rechargeable seawater battery"
        ],
        "section": "topic-other-chemistries",
        "definition": "A battery that uses seawater as its electrolyte or positive reactant. Seawater-activated primaries, such as magnesium–silver chloride cells, sit dry for years and start when immersed, powering sonobuoys and life-jacket lights. Rechargeable versions pull sodium ions from seawater through a NASICON ceramic into a sealed negative electrode, with oxygen reactions on the open seawater side.",
        "related": [
          "nasicon",
          "sodium-ion",
          "primary-cell",
          "zinc-air",
          "aqueous-battery"
        ],
        "url": "https://lemonergy.com/learn/glossary/seawater-battery/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "electrolyte"
        ]
      }
    },
    {
      "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:negative-electrode",
      "type": "Term",
      "label": "Negative electrode",
      "properties": {
        "id": "negative-electrode",
        "name": "Negative electrode",
        "section": "topic-components",
        "definition": "The electrode at the lower potential, usually graphite on copper foil in a lithium-ion cell. It holds the lithium when the cell is charged and releases it on discharge, and industry calls it the anode.",
        "related": [
          "anode",
          "graphite",
          "positive-electrode",
          "copper-foil"
        ],
        "lesson": "fundamentals/cell-anatomy/#anode-cathode",
        "example": {
          "title": "Keep the polarity name",
          "text": "Graphite remains the negative electrode during charge and discharge, while the anode/cathode reaction labels change with operating direction."
        },
        "url": "https://lemonergy.com/learn/glossary/negative-electrode/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "id": "term:cobalt",
      "type": "Term",
      "label": "Cobalt",
      "properties": {
        "id": "cobalt",
        "name": "Cobalt",
        "section": "topic-sustainability",
        "definition": "The metal that stabilises layered-oxide cathodes, mined largely in the Democratic Republic of Congo under scrutiny for working conditions. Its price and ethics have driven the industry from LCO and NMC111 towards high-nickel and cobalt-free LFP.",
        "related": [
          "nmc",
          "lco",
          "high-nickel",
          "critical-raw-materials",
          "due-diligence"
        ],
        "url": "https://lemonergy.com/learn/glossary/cobalt/",
        "mentions": []
      }
    },
    {
      "id": "term:layered-oxide",
      "type": "Term",
      "label": "Layered oxide",
      "properties": {
        "id": "layered-oxide",
        "name": "Layered oxide",
        "abbr": "LTMO",
        "aka": [
          "layered transition-metal oxide",
          "α-NaFeO₂ structure",
          "O3 structure",
          "P2 structure"
        ],
        "section": "topic-chemistries",
        "definition": "The crystal structure of LCO, NMC and NCA: close-packed oxygen layers with lithium and transition-metal ions in alternate layers of octahedral sites, so lithium moves in two-dimensional sheets. The structure offers high capacity and voltage but can distort or mix cations when deeply delithiated. Sodium versions are labelled O3 or P2 by their stacking.",
        "related": [
          "nmc",
          "lco",
          "nca",
          "structural-degradation",
          "spinel-structure",
          "sodium-ion"
        ],
        "url": "https://lemonergy.com/learn/glossary/layered-oxide/",
        "mentions": [
          "stacking"
        ]
      }
    }
  ]
}