{ "node": { "id": "term:porous-electrode", "type": "Term", "label": "Porous electrode", "properties": { "id": "porous-electrode", "name": "Porous electrode", "section": "topic-components", "definition": "An electrode made of active-material particles, conductive additive and binder with electrolyte-filled pores between them. 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It makes up most of the electrode coating; the rest is binder and conductive additive.", "related": [ "cathode-active-material", "anode-active-material", "binder", "conductive-additive", "specific-capacity" ], "lesson": "fundamentals/cell-architecture/#composite", "example": { "title": "Choose a mass basis", "text": "A 100 g coating containing 95 g active material has different specific-capacity numbers when normalized to active mass versus total coating mass." }, "url": "https://lemonergy.com/learn/glossary/active-material/", "mentions": [ "electrode", "graphite", "coating" ] } }, { "id": "term:porous-electrode-theory", "type": "Term", "label": "Porous-electrode theory", "properties": { "id": "porous-electrode-theory", "name": "Porous-electrode theory", "section": "topic-transport", "definition": "The framework, due to Newman and co-workers, that treats a porous electrode as two overlapping continua — solid and electrolyte — exchanging current everywhere through their shared surface. 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The structure shortens the paths ions must travel through a thick electrode and enlarges the reactive surface, so a cell can keep its energy while charging faster.", "related": [ "tortuosity", "areal-loading", "porous-electrode", "fast-charging", "current-collector", "xfc" ], "url": "https://lemonergy.com/learn/glossary/3d-electrode/", "mentions": [ "electrode", "coating" ] } }, { "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:binder", "type": "Term", "label": "Binder", "properties": { "id": "binder", "name": "Binder", "section": "topic-components", "definition": "A polymer that holds electrode particles to each other and to the foil — typically PVDF for positive electrodes and CMC with SBR for graphite. It stores no charge, so cell designers use as little as the electrode needs.", "related": [ "active-material", "conductive-additive", "slurry", "pvdf", "nmp", "paa" ], "lesson": "fundamentals/cell-architecture/#composite", "example": { "title": "Balance coating functions", "text": "Increasing binder fraction at fixed coating mass leaves less mass for active material and conductive additive. Adhesion and capacity are separate design considerations." }, "url": "https://lemonergy.com/learn/glossary/binder/", "mentions": [ "electrode", "graphite", "cmc", "sbr" ] } }, { "id": "term:conductive-additive", "type": "Term", "label": "Conductive additive", "properties": { "id": "conductive-additive", "name": "Conductive additive", "aka": [ "carbon black", "conductive carbon" ], "section": "topic-components", "definition": "Fine carbon, such as carbon black or carbon nanotubes, added in small amounts to an electrode so that electrons can reach every active particle. Many active materials conduct electrons poorly on their own.", "related": [ "active-material", "binder", "electronic-conductivity", "slurry" ], "lesson": "fundamentals/cell-architecture/#composite", "example": { "title": "Distribution matters", "text": "Two coatings with the same additive mass can have different electronic connectivity if the additive is distributed differently." }, "url": "https://lemonergy.com/learn/glossary/conductive-additive/", "mentions": [ "electrode", "carbon-nanotube" ] } }, { "id": "lesson:fundamentals/cell-architecture/", "type": "Lesson", "label": "Lesson 1B · Cell architecture", "properties": { "url": "https://lemonergy.com/learn/fundamentals/cell-architecture/" } }, { "id": "visual:porous", "type": "Visual", "label": "Porosity reduces effective transport", "properties": { "title": "Porosity reduces effective transport", "summary": "A Bruggeman relation approximates transport through a porous medium.", "readout": "At 40% porosity, D_eff is 25.298% of bulk diffusivity.", "formula": "D_eff = D εᵇ", "note": "An empirical pore-structure assumption; actual tortuosity must be characterized.", "software": { "status": "reference", "label": "Reference concept", "body": "The flux helper accepts a supplied diffusivity. It does not estimate porosity or tortuosity. The shown D_eff = D εᵇ relationship is an explicit teaching assumption.", "href": "../transport/ficks-first-law/" }, "html": "
Effective diffusivity fraction
Effective diffusivity fractionPorosity ε (fraction) versus D_eff / D (fraction). εᵇ; Straight-pore scaling ε. Interpretation follows the graphs.000.250.250.50.50.750.7511Porosity ε (fraction)D_eff / D (fraction)
εᵇStraight-pore scaling ε (dashed)
" } }, { "id": "reference:doyle-model", "type": "Reference", "label": "Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell", "properties": { "title": "Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell", "publisher": "Journal of The Electrochemical Society", "url": "https://doi.org/10.1149/1.2221597", "type": "Research article", "scope": "Porous-electrode transport and insertion-cell modeling; foundational work rather than a specification for a particular commercial cell.", "year": 1993, "authors": [ "Marc Doyle", "Thomas F. Fuller", "John Newman" ], "accessed": "2026-10-27" } } ] }