{
  "node": {
    "id": "term:nvp",
    "type": "Term",
    "label": "Sodium vanadium phosphate",
    "properties": {
      "id": "nvp",
      "name": "Sodium vanadium phosphate",
      "abbr": "NVP",
      "aka": [
        "Na₃V₂(PO₄)₃"
      ],
      "section": "topic-other-chemistries",
      "definition": "A polyanionic sodium-ion positive electrode, Na₃V₂(PO₄)₃, with a NASICON-type framework of open three-dimensional channels through which sodium moves quickly. Cells reach about 2.9–3.1 V nominal and suit high power and very long cycle life; vanadium makes the material costlier than iron-based NFPP.",
      "related": [
        "sodium-ion",
        "polyanionic-cathode",
        "nfpp",
        "hard-carbon",
        "power-cell-energy-cell"
      ],
      "url": "https://lemonergy.com/learn/glossary/nvp/",
      "mentions": [
        "electrode",
        "positive-electrode",
        "cycle-life"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:belongsTo/term:nvp/topic:topic-other-chemistries",
      "source": "term:nvp",
      "target": "topic:topic-other-chemistries",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:relatedTo/term:nvp/term:sodium-ion",
      "source": "term:nvp",
      "target": "term:sodium-ion",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:nvp/term:polyanionic-cathode",
      "source": "term:nvp",
      "target": "term:polyanionic-cathode",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:nvp/term:nfpp",
      "source": "term:nvp",
      "target": "term:nfpp",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:nvp/term:hard-carbon",
      "source": "term:nvp",
      "target": "term:hard-carbon",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:nvp/term:power-cell-energy-cell",
      "source": "term:nvp",
      "target": "term:power-cell-energy-cell",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/nvp/electrode",
      "source": "term:nvp",
      "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/nvp/positive-electrode",
      "source": "term:nvp",
      "target": "term:positive-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/nvp/cycle-life",
      "source": "term:nvp",
      "target": "term:cycle-life",
      "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-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 and a layered-oxide (NFM), polyanionic (NFPP, NVP) or Prussian-blue positive. It uses no lithium or cobalt and needs no copper foil, so it can be stored at 0 V, at the cost of lower energy density.",
        "related": [
          "hard-carbon",
          "nfpp",
          "lithium-ion",
          "energy-density",
          "stationary-storage",
          "seawater-battery"
        ],
        "aka": [
          "SIB",
          "Na-ion battery",
          "sodium-ion cell"
        ],
        "url": "https://lemonergy.com/learn/glossary/sodium-ion/",
        "mentions": [
          "copper-foil",
          "nfm",
          "nvp",
          "cobalt",
          "polyanionic-cathode"
        ]
      }
    },
    {
      "id": "term:polyanionic-cathode",
      "type": "Term",
      "label": "Polyanionic cathode",
      "properties": {
        "id": "polyanionic-cathode",
        "name": "Polyanionic cathode",
        "aka": [
          "polyanion cathode",
          "NVPF",
          "NFPP",
          "phosphate cathode"
        ],
        "section": "topic-other-chemistries",
        "definition": "A positive material built from transition metals and polyanion groups such as PO₄³⁻, SO₄²⁻ or P₂O₇⁴⁻. The strongly bonded groups raise the voltage through the inductive effect and hold oxygen tightly, giving long life and safety at some cost in capacity and conductivity. LFP is the lithium example; Na₃V₂(PO₄)₂F₃ and iron-based Na₄Fe₃(PO₄)₂P₂O₇ serve sodium-ion cells.",
        "related": [
          "lfp",
          "olivine-structure",
          "sodium-ion",
          "prussian-blue-analogue",
          "layered-oxide"
        ],
        "url": "https://lemonergy.com/learn/glossary/polyanionic-cathode/",
        "mentions": [
          "nfpp"
        ]
      }
    },
    {
      "id": "term:nfpp",
      "type": "Term",
      "label": "Sodium iron pyrophosphate-phosphate",
      "properties": {
        "id": "nfpp",
        "name": "Sodium iron pyrophosphate-phosphate",
        "abbr": "NFPP",
        "aka": [
          "Na₄Fe₃(PO₄)₂P₂O₇",
          "sodium iron phosphate-pyrophosphate"
        ],
        "section": "topic-other-chemistries",
        "definition": "A polyanionic sodium-ion positive electrode, Na₄Fe₃(PO₄)₂P₂O₇, made from cheap iron and phosphate. With a hard-carbon negative it gives cells of about 2.8–3.0 V nominal with long cycle life and good thermal stability, but less energy than layered oxides. It plays the role LFP plays among lithium-ion chemistries.",
        "related": [
          "sodium-ion",
          "polyanionic-cathode",
          "hard-carbon",
          "lfp",
          "nvp",
          "nfm"
        ],
        "url": "https://lemonergy.com/learn/glossary/nfpp/",
        "mentions": [
          "electrode",
          "positive-electrode",
          "cycle-life"
        ]
      }
    },
    {
      "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:power-cell-energy-cell",
      "type": "Term",
      "label": "Power cell and energy cell",
      "properties": {
        "id": "power-cell-energy-cell",
        "name": "Power cell and energy cell",
        "section": "topic-applications",
        "definition": "Two design points of the same chemistry: a power cell has thin, porous electrodes and many tabs for high current and fast charging; an energy cell has thick, dense electrodes for maximum watt-hours. A hybrid car wants the first, a long-range car the second.",
        "related": [
          "specific-power",
          "specific-energy",
          "areal-loading",
          "cell-design"
        ],
        "url": "https://lemonergy.com/learn/glossary/power-cell-energy-cell/",
        "mentions": [
          "fast-charging"
        ]
      }
    },
    {
      "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:positive-electrode",
      "type": "Term",
      "label": "Positive electrode",
      "properties": {
        "id": "positive-electrode",
        "name": "Positive electrode",
        "section": "topic-components",
        "definition": "The electrode at the higher potential: a lithium metal oxide or phosphate coated on aluminium foil. It is the lithium source when a cell is built, and industry calls it the cathode.",
        "related": [
          "cathode",
          "cathode-active-material",
          "negative-electrode",
          "aluminium-foil"
        ],
        "lesson": "fundamentals/cell-anatomy/#anode-cathode",
        "example": {
          "title": "Polarity and reaction",
          "text": "The positive electrode retains its polarity label while its electrochemical reaction reverses between charge and discharge."
        },
        "url": "https://lemonergy.com/learn/glossary/positive-electrode/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "id": "term:cycle-life",
      "type": "Term",
      "label": "Cycle life",
      "properties": {
        "id": "cycle-life",
        "name": "Cycle life",
        "section": "topic-ratings",
        "definition": "The number of full charge–discharge cycles a cell completes before its capacity falls to a stated fraction, usually 80 %, of its initial value under defined conditions. LFP cells reach several thousand cycles; high-energy NMC fewer.",
        "unit": "cycles",
        "related": [
          "end-of-life",
          "capacity-fade",
          "depth-of-discharge",
          "calendar-life",
          "equivalent-full-cycle",
          "cycle-life-test"
        ],
        "url": "https://lemonergy.com/learn/glossary/cycle-life/",
        "mentions": []
      }
    }
  ]
}