{
  "node": {
    "id": "term:polysulfide-shuttle",
    "type": "Term",
    "label": "Polysulfide shuttle",
    "properties": {
      "id": "polysulfide-shuttle",
      "name": "Polysulfide shuttle",
      "aka": [
        "shuttle effect",
        "polysulfide shuttle effect"
      ],
      "section": "topic-aging",
      "definition": "The parasitic loop in a lithium–sulfur cell in which long-chain polysulfides, Li₂Sₙ with n from 4 to 8, dissolve into the electrolyte, diffuse to the lithium electrode, are reduced there and diffuse back. It causes self-discharge, low coulombic efficiency and loss of sulfur; lithium nitrate, which passivates the lithium surface, is the usual additive against it.",
      "related": [
        "lithium-sulfur",
        "self-discharge",
        "coulombic-efficiency",
        "lithium-metal-anode",
        "electrolyte-additive",
        "conversion-reaction"
      ],
      "url": "https://lemonergy.com/learn/glossary/polysulfide-shuttle/",
      "mentions": [
        "electrode",
        "electrolyte"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:6598",
      "source": "term:polysulfide-shuttle",
      "target": "topic:topic-aging",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:6599",
      "source": "term:polysulfide-shuttle",
      "target": "term:lithium-sulfur",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6600",
      "source": "term:polysulfide-shuttle",
      "target": "term:self-discharge",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6601",
      "source": "term:polysulfide-shuttle",
      "target": "term:coulombic-efficiency",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6602",
      "source": "term:polysulfide-shuttle",
      "target": "term:lithium-metal-anode",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6603",
      "source": "term:polysulfide-shuttle",
      "target": "term:electrolyte-additive",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:6604",
      "source": "term:polysulfide-shuttle",
      "target": "term:conversion-reaction",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/polysulfide-shuttle/electrode",
      "source": "term:polysulfide-shuttle",
      "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/polysulfide-shuttle/electrolyte",
      "source": "term:polysulfide-shuttle",
      "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-aging",
      "type": "Topic",
      "label": "Aging and degradation",
      "properties": {
        "id": "topic-aging",
        "name": "Aging and degradation",
        "lede": "Why a cell loses capacity and gains resistance, and the mechanisms behind it.",
        "context": "Separate mechanisms, observations and fitted models.",
        "example": "Capacity loss and resistance rise can have different causes; a film-growth curve cannot identify both.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-aging/",
        "lesson_label": "Open aging"
      }
    },
    {
      "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:self-discharge",
      "type": "Term",
      "label": "Self-discharge",
      "properties": {
        "id": "self-discharge",
        "name": "Self-discharge",
        "section": "topic-charging",
        "definition": "The slow loss of stored charge while a cell is not in use. An unexpected rise can signal a leakage path or a soft internal short.",
        "unit": "%/month",
        "related": [
          "internal-short-circuit",
          "calendar-aging",
          "k-value",
          "calendar-life",
          "self-discharge-test"
        ],
        "lesson": "fundamentals/battery-aging/#check-yourself",
        "url": "https://lemonergy.com/learn/glossary/self-discharge/",
        "mentions": []
      }
    },
    {
      "id": "term:coulombic-efficiency",
      "type": "Term",
      "label": "Coulombic efficiency",
      "properties": {
        "id": "coulombic-efficiency",
        "name": "Coulombic efficiency",
        "abbr": "CE",
        "section": "topic-ratings",
        "definition": "Charge delivered on discharge divided by charge put in on the previous charge. A healthy lithium-ion cell exceeds 99.9 %; the missing fraction is lithium lost to side reactions, so CE is an early and sensitive aging signal.",
        "formula": "CE = Q_discharge / Q_charge",
        "unit": "%",
        "related": [
          "energy-efficiency",
          "loss-of-lithium-inventory",
          "sei",
          "formation"
        ],
        "example": {
          "title": "Compare charge in and charge out",
          "text": "If a defined test charges 5.00 Ah and subsequently discharges 4.95 Ah over the chosen voltage window, its coulombic efficiency is 99%. This ratio alone does not include voltage-related energy loss."
        },
        "url": "https://lemonergy.com/learn/glossary/coulombic-efficiency/",
        "mentions": []
      }
    },
    {
      "id": "term:lithium-metal-anode",
      "type": "Term",
      "label": "Lithium metal anode",
      "properties": {
        "id": "lithium-metal-anode",
        "name": "Lithium metal anode",
        "section": "topic-components",
        "definition": "A negative electrode made of lithium metal itself. It stores about ten times more charge per gram than graphite, which is the main attraction of solid-state cells, but it is reactive and prone to uneven deposits.",
        "related": [
          "lithium-metal-battery",
          "dendrite",
          "solid-state-battery",
          "anode-free"
        ],
        "lesson": "fundamentals/solid-state-cell-production/#why",
        "url": "https://lemonergy.com/learn/glossary/lithium-metal-anode/",
        "mentions": [
          "electrode",
          "negative-electrode",
          "graphite"
        ]
      }
    },
    {
      "id": "term:electrolyte-additive",
      "type": "Term",
      "label": "Electrolyte additive",
      "properties": {
        "id": "electrolyte-additive",
        "name": "Electrolyte additive",
        "aka": [
          "VC",
          "FEC"
        ],
        "section": "topic-electrolytes",
        "definition": "A compound added to the electrolyte at a few percent to improve one property — vinylene carbonate and fluoroethylene carbonate build a tougher SEI, others suppress gassing or overcharge. Additive packages are among a cell maker’s closest secrets.",
        "related": [
          "electrolyte",
          "sei",
          "formation",
          "gas-generation",
          "libob"
        ],
        "url": "https://lemonergy.com/learn/glossary/electrolyte-additive/",
        "mentions": [
          "overcharge",
          "vc",
          "fec"
        ]
      }
    },
    {
      "id": "term:conversion-reaction",
      "type": "Term",
      "label": "Conversion reaction",
      "properties": {
        "id": "conversion-reaction",
        "name": "Conversion reaction",
        "section": "topic-electrochemistry",
        "definition": "An electrode reaction in which the host compound is broken down and reformed, as sulfur or a metal fluoride is, rather than lithium slotting into an intact structure. Conversion materials store more charge than intercalation hosts but suffer large volume change and voltage hysteresis.",
        "related": [
          "intercalation",
          "alloying",
          "lithium-sulfur",
          "voltage-hysteresis"
        ],
        "url": "https://lemonergy.com/learn/glossary/conversion-reaction/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "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: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"
        ]
      }
    }
  ]
}