Battery knowledge · Capacity, energy, power and ratings
Theoretical capacity
The capacity a material would deliver if every available lithium ion took part, computed from Faraday’s law and the molar mass. Practical capacity is lower because not all the lithium can be removed reversibly. [1]
- Unit
- mAh/g
- Relationship
- Q = n·F / (3.6·M)
Example
Compute a one-electron capacity
For an illustrative active material with molar mass 100 g/mol and one transferred electron per formula unit, nF/(3.6M) is about 268 mAh/g. Inactive material and incomplete utilization reduce the cell-level value.
Explore the graph
Electron count and molar mass connect electrical charge to transformed material.
268 mAh/g for 1 electron(s) and 100 g/mol.
Q_theoretical = nF / (3.6M); m = charge × M / (nF)
Illustrative model. Assumes complete Faradaic conversion and 100% utilization. Practical reversible capacity can be lower; the material identity is not inferred from molar mass.
Use in Lemonergy
Separate nameplate ratings from test results.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Technical references
- Quantities, Units and Symbols in Physical Chemistry, 3rd edition, 2nd printing
IUPAC · 2011
Technical reference · Physical-chemistry notation, thermodynamics, electrochemistry and transport quantities.
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- The International System of Units (SI), 9th edition
Bureau International des Poids et Mesures · 2026
Topic background · Definitions of SI units and coherent derived units; 2026 revision.
- Battery Test Manual For Electric Vehicles, Revision 3
Jon P. Christopherson · Idaho National Laboratory · 2015
Topic background · Performance characterization, pulse resistance/power, life testing and reference performance tests; historical 2015 edition.