{
  "node": {
    "id": "term:sodium-sulfur",
    "type": "Term",
    "label": "Sodium–sulfur battery",
    "properties": {
      "id": "sodium-sulfur",
      "name": "Sodium–sulfur battery",
      "abbr": "NaS",
      "aka": [
        "Na–S",
        "sodium sulphur battery"
      ],
      "section": "topic-other-chemistries",
      "definition": "A high-temperature cell of molten sodium and molten sulfur separated by a β″-alumina ceramic electrolyte, operating at about 300–350 °C and giving roughly 2 V. Made commercially by NGK in Japan since the early 2000s, it has supplied hundreds of megawatts of six-hour grid storage; heater losses and fire risk from molten reactants are its drawbacks.",
      "related": [
        "sodium-nickel-chloride",
        "stationary-storage",
        "solid-electrolyte",
        "lithium-sulfur",
        "long-duration-storage"
      ],
      "url": "https://lemonergy.com/learn/glossary/sodium-sulfur/",
      "mentions": [
        "electrolyte"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:6013",
      "source": "term:sodium-sulfur",
      "target": "topic:topic-other-chemistries",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:6014",
      "source": "term:sodium-sulfur",
      "target": "term:sodium-nickel-chloride",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6015",
      "source": "term:sodium-sulfur",
      "target": "term:stationary-storage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6016",
      "source": "term:sodium-sulfur",
      "target": "term:solid-electrolyte",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6017",
      "source": "term:sodium-sulfur",
      "target": "term:lithium-sulfur",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6018",
      "source": "term:sodium-sulfur",
      "target": "term:long-duration-storage",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/sodium-sulfur/electrolyte",
      "source": "term:sodium-sulfur",
      "target": "term:electrolyte",
      "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:sodium-nickel-chloride",
      "type": "Term",
      "label": "Sodium–nickel chloride battery",
      "properties": {
        "id": "sodium-nickel-chloride",
        "name": "Sodium–nickel chloride battery",
        "abbr": "ZEBRA",
        "aka": [
          "Na–NiCl₂",
          "molten-salt battery"
        ],
        "section": "topic-other-chemistries",
        "definition": "A high-temperature cell, run at about 270–350 °C, with molten sodium as negative, nickel and nickel chloride in molten sodium tetrachloroaluminate as positive, and a β″-alumina ceramic electrolyte between them, giving 2.58 V. Failed cells fail to low resistance, so a series string keeps working; it has served in buses, telecom backup and grid storage.",
        "related": [
          "sodium-sulfur",
          "solid-electrolyte",
          "electric-bus",
          "stationary-storage",
          "liquid-metal-battery"
        ],
        "url": "https://lemonergy.com/learn/glossary/sodium-nickel-chloride/",
        "mentions": [
          "electrolyte",
          "string"
        ]
      }
    },
    {
      "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:solid-electrolyte",
      "type": "Term",
      "label": "Solid electrolyte",
      "properties": {
        "id": "solid-electrolyte",
        "name": "Solid electrolyte",
        "section": "topic-electrolytes",
        "definition": "A solid ion conductor that replaces the liquid electrolyte in an all-solid-state cell. Oxide, sulfide, halide and polymer families each need a different production route.",
        "related": [
          "solid-state-battery",
          "electrolyte",
          "sintering",
          "stack-pressure",
          "ionic-conductivity",
          "superionic-conductor"
        ],
        "lesson": "fundamentals/solid-state-cell-production/#families",
        "url": "https://lemonergy.com/learn/glossary/solid-electrolyte/",
        "mentions": []
      }
    },
    {
      "id": "term:lithium-sulfur",
      "type": "Term",
      "label": "Lithium–sulfur battery",
      "properties": {
        "id": "lithium-sulfur",
        "name": "Lithium–sulfur battery",
        "abbr": "Li–S",
        "section": "topic-other-chemistries",
        "definition": "A cell pairing a lithium-metal negative electrode with a sulfur positive electrode, which is cheap, light and converts rather than intercalates. Theoretical specific energy is very high; dissolving polysulfides and short cycle life are the obstacles.",
        "related": [
          "conversion-reaction",
          "lithium-metal-battery",
          "specific-energy",
          "polysulfide-shuttle"
        ],
        "url": "https://lemonergy.com/learn/glossary/lithium-sulfur/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "positive-electrode",
          "cycle-life"
        ]
      }
    },
    {
      "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:electrolyte",
      "type": "Term",
      "label": "Electrolyte",
      "properties": {
        "id": "electrolyte",
        "name": "Electrolyte",
        "section": "topic-electrolytes",
        "definition": "The ion-conducting medium between the electrodes. In a liquid-electrolyte cell it fills the pores of both electrodes and the separator, so it is not a separate structural layer.",
        "related": [
          "lithium-salt",
          "carbonate-solvent",
          "electrolyte-additive",
          "ionic-conductivity",
          "solid-electrolyte",
          "ionic-liquid-electrolyte"
        ],
        "lesson": "fundamentals/cell-architecture/#electrolyte",
        "example": {
          "title": "Ions and electrons",
          "text": "Electrolyte carries ions between electrodes; the external circuit carries electrons. The two paths serve different roles."
        },
        "url": "https://lemonergy.com/learn/glossary/electrolyte/",
        "mentions": [
          "separator"
        ]
      }
    }
  ]
}