{ "node": { "id": "term:titration-gas-chromatography", "type": "Term", "label": "Titration gas chromatography", "properties": { "id": "titration-gas-chromatography", "name": "Titration gas chromatography", "abbr": "TGC", "aka": [ "water titration", "inactive lithium quantification" ], "section": "topic-analysis", "definition": "Quantifying metallic lithium in a cycled electrode by reacting it with water and measuring the hydrogen released by gas chromatography. Most SEI lithium compounds give off no hydrogen, so the method separates dead metallic lithium from SEI lithium down to about a microgram; it showed that unreacted metal dominates capacity loss in lithium-metal cells.", "formula": "2Li + 2H₂O → 2LiOH + H₂", "related": [ "dead-lithium", "lithium-plating", "lithium-metal-battery", "loss-of-lithium-inventory", "gas-chromatography-mass-spectrometry" ], "example": { "title": "Use the reaction stoichiometry", "text": "In the ideal reaction 2Li + 2H₂O → 2LiOH + H₂, 1 μmol of measured H₂ corresponds to 2 μmol of metallic Li. Interfering gas-producing species and instrument calibration must be assessed." }, "notes": [ "This is a stoichiometric interpretation, not instructions for opening or reacting a battery." ], "url": "https://lemonergy.com/learn/glossary/titration-gas-chromatography/", "mentions": [ "electrode", "sei" ] } }, "edges": [ { "id": "edge:5591", "source": "term:titration-gas-chromatography", "target": "topic:topic-analysis", "type": "belongsTo", "properties": { "sourceFile": "terms.json" } }, { "id": "edge:5592", "source": "term:titration-gas-chromatography", "target": "term:dead-lithium", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5593", "source": "term:titration-gas-chromatography", "target": "term:lithium-plating", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5594", "source": "term:titration-gas-chromatography", "target": "term:lithium-metal-battery", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5595", "source": "term:titration-gas-chromatography", "target": "term:loss-of-lithium-inventory", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:5596", "source": "term:titration-gas-chromatography", "target": "term:gas-chromatography-mass-spectrometry", "type": "relatedTo", "properties": { "sourceFile": "terms.json", "meaning": "Related context; not a causal claim" } }, { "id": "edge:mentions/titration-gas-chromatography/electrode", "source": "term:titration-gas-chromatography", "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/titration-gas-chromatography/sei", "source": "term:titration-gas-chromatography", "target": "term:sei", "type": "mentions", "properties": { "sourceFile": "terms.json", "method": "build_glossary.mention_index + mentions", "field": "definition", "meaning": "Text mention; not a causal claim" } }, { "id": "edge:5599", "source": "term:titration-gas-chromatography", "target": "visual:lithium-stoichiometry", "type": "illustratedBy", "properties": { "sourceFile": "visual-pages.json" } } ], "neighbors": [ { "id": "topic:topic-analysis", "type": "Topic", "label": "Materials analysis and post-mortem", "properties": { "id": "topic-analysis", "name": "Materials analysis and post-mortem", "lede": "The laboratory techniques that look inside electrodes, interphases and electrolytes to see what a cell is made of and how it aged.", "context": "Connect results with scale and specimen preparation.", "example": "Surface and bulk measurements may find different compositions in the same electrode without contradiction.", "lesson_url": "https://lemonergy.com/learn/labs/battery-materials-lab/", "lesson_label": "Open materials lab" } }, { "id": "term:dead-lithium", "type": "Term", "label": "Dead lithium", "properties": { "id": "dead-lithium", "name": "Dead lithium", "aka": [ "inactive lithium" ], "section": "topic-aging", "definition": "Plated lithium metal that has lost electrical contact with the electrode, usually because SEI formed around it. It can no longer take part in cycling, so every gram of it is permanent capacity loss.", "related": [ "lithium-plating", "loss-of-lithium-inventory", "sei", "titration-gas-chromatography" ], "url": "https://lemonergy.com/learn/glossary/dead-lithium/", "mentions": [ "electrode" ] } }, { "id": "term:lithium-plating", "type": "Term", "label": "Lithium plating", "properties": { "id": "lithium-plating", "name": "Lithium plating", "section": "topic-aging", "definition": "Lithium metal depositing on the negative-electrode surface instead of intercalating into it. It is promoted by charging at low temperature or high current.", "related": [ "dendrite", "fast-charging", "intercalation", "np-ratio", "dead-lithium", "electrodeposition" ], "lesson": "fundamentals/battery-aging/#plating", "url": "https://lemonergy.com/learn/glossary/lithium-plating/", "mentions": [] } }, { "id": "term:lithium-metal-battery", "type": "Term", "label": "Lithium-metal battery", "properties": { "id": "lithium-metal-battery", "name": "Lithium-metal battery", "section": "topic-other-chemistries", "definition": "A rechargeable cell whose negative electrode is lithium metal rather than a host material. It promises much higher energy density than lithium-ion, but lithium deposits unevenly on charge, so dendrites and short life have kept it from the mass market.", "related": [ "lithium-metal-anode", "dendrite", "solid-state-battery", "anode-free" ], "url": "https://lemonergy.com/learn/glossary/lithium-metal-battery/", "mentions": [ "electrode", "negative-electrode", "energy-density" ] } }, { "id": "term:loss-of-lithium-inventory", "type": "Term", "label": "Loss of lithium inventory", "properties": { "id": "loss-of-lithium-inventory", "name": "Loss of lithium inventory", "abbr": "LLI", "section": "topic-aging", "definition": "The degradation mode in which cyclable lithium is consumed by side reactions — SEI growth, plating, electrolyte decomposition — and can no longer shuttle between the electrodes. It is the dominant cause of capacity fade in most lithium-ion cells.", "related": [ "sei", "lithium-plating", "capacity-fade", "loss-of-active-material", "coulombic-efficiency" ], "url": "https://lemonergy.com/learn/glossary/loss-of-lithium-inventory/", "mentions": [ "electrolyte", "aging-mechanism", "electrolyte-decomposition" ] } }, { "id": "term:gas-chromatography-mass-spectrometry", "type": "Term", "label": "Gas chromatography–mass spectrometry", "properties": { "id": "gas-chromatography-mass-spectrometry", "name": "Gas chromatography–mass spectrometry", "abbr": "GC-MS", "aka": [ "gas chromatography", "GC" ], "section": "topic-analysis", "definition": "Separating the volatile components of a sample in a heated column and identifying each by its mass spectrum. It measures electrolyte composition and aging products such as transesterified solvents and oligomers; with thermal-conductivity detection it also quantifies hydrogen, carbon monoxide, carbon dioxide and hydrocarbons in cell and vent gas.", "related": [ "electrolyte-decomposition", "off-gas", "gas-generation", "differential-electrochemical-mass-spectrometry", "post-mortem" ], "url": "https://lemonergy.com/learn/glossary/gas-chromatography-mass-spectrometry/", "mentions": [ "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:sei", "type": "Term", "label": "Solid–electrolyte interphase", "properties": { "id": "sei", "name": "Solid–electrolyte interphase", "abbr": "SEI", "section": "topic-aging", "definition": "A film of electrolyte reaction products on the negative-electrode particles — graphite, and also silicon or lithium metal. It protects the electrode from further reaction but grows slowly for the whole life of the cell, consuming cyclable lithium.", "related": [ "passivation", "formation", "calendar-aging", "loss-of-lithium-inventory", "cei" ], "lesson": "fundamentals/battery-aging/#sei", "url": "https://lemonergy.com/learn/glossary/sei/", "mentions": [ "electrode", "graphite", "electrolyte" ] } }, { "id": "visual:lithium-stoichiometry", "type": "Visual", "label": "A reaction equation predicts a molar signal", "properties": { "title": "A reaction equation predicts a molar signal", "summary": "The reaction consumes two moles of lithium per mole of hydrogen.", "readout": "For 1 mg of pure metallic lithium, the equation predicts 72.05 μmol of hydrogen.", "formula": "2 Li + 2 H₂O → 2 LiOH + H₂; n(H₂) = n(Li) / 2", "note": "Assumes pure metallic lithium and complete stoichiometric reaction. Real analysis requires calibration, collection efficiency and interference assessment.", "software": { "status": "reference", "label": "Reference concept", "body": "This is a stoichiometric explanation of the term, not a laboratory procedure or analytical calibration. The software does not separate species in a real electrode sample.", "href": "../chapter-1/" }, "html": "
Ideal hydrogen amount from metallic lithium
Ideal hydrogen amount from metallic lithiumMetallic lithium mass (mg) versus Hydrogen amount (μmol). Stoichiometric amount. Interpretation follows the graphs.001802.536055407.572010Metallic lithium mass (mg)Hydrogen amount (μmol)
Stoichiometric amount
" } } ] }