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"label": "Standard hydrogen electrode",
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"id": "standard-hydrogen-electrode",
"name": "Standard hydrogen electrode",
"abbr": "SHE",
"section": "topic-electrochemistry",
"definition": "The reference electrode that defines zero on the electrochemical potential scale: platinum in a solution of unit hydrogen-ion activity, bubbled with hydrogen at 1 bar. Battery work mostly uses the Li/Li⁺ scale instead, which sits 3.04 V below it, so 4.2 V vs Li/Li⁺ is about 1.16 V vs SHE.",
"formula": "E(vs SHE) ≈ E(vs Li/Li⁺) − 3.04 V",
"unit": "V",
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"title": "Convert a reference potential",
"text": "Using the approximate standard-state offset of −3.04 V for Li/Li⁺ versus SHE, an electrode at 4.0 V versus Li/Li⁺ is approximately 0.96 V versus SHE. Actual reference conditions and solvent conventions matter."
},
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"id": "term:reference-electrode",
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"id": "term:standard-potential",
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"id": "standard-potential",
"name": "Standard electrode potential",
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"section": "topic-electrochemistry",
"definition": "An electrode’s potential under standard conditions, tabulated against the standard hydrogen electrode. Lithium’s −3.04 V is the most negative of any metal, which is why lithium cells have the highest voltages.",
"unit": "V",
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"id": "term:electrode",
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"label": "Activities shift equilibrium potential",
"properties": {
"title": "Activities shift equilibrium potential",
"summary": "The logarithm of the reaction quotient changes equilibrium potential; reference electrodes set the voltage zero.",
"readout": "A tenfold increase in Q shifts E by −59.16 mV at 25 °C for n = 1.",
"formula": "E − E° = −(RT/nF) ln Q; E(vs SHE) ≈ E(vs Li/Li⁺) − 3.04 V",
"note": "Q is dimensionless activity quotient, not electrical charge. The −3.04 V reference offset is an approximate conventional value; it is not recomputed with temperature.",
"software": {
"status": "reference",
"label": "Reference concept",
"body": "This is a reference thermodynamic calculation. battery-core does not construct an activity model or compute OCV from a half-reaction.",
"href": "../chapter-1/"
},
"html": "Potential shift by activity quotient