Battery knowledge · Electrochemistry fundamentals
Standard hydrogen electrode
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.
- Abbreviation
- SHE
- Unit
- V
- Relationship
- E(vs SHE) ≈ E(vs Li/Li⁺) − 3.04 V
Example
Convert a reference potential
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.
Explore the graph
The logarithm of the reaction quotient changes equilibrium potential; reference electrodes set the voltage zero.
A tenfold increase in Q shifts E by −59.16 mV at 25 °C for n = 1.
E − E° = −(RT/nF) ln Q; E(vs SHE) ≈ E(vs Li/Li⁺) − 3.04 V
Illustrative model. 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.
Use in Lemonergy
Connect reaction sites and transport paths.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Quantities, Units and Symbols in Physical Chemistry, 3rd edition, 2nd printing
IUPAC · 2011
Topic background · Physical-chemistry notation, thermodynamics, electrochemistry and transport quantities.