
228 Electrochemically Enabled Sustainability
6.2.2 Application of First-Principles Calculations to Cathode Design
6.2.2.1 Lithium/Sodium Intercalation Voltage
The equilibrium intercalation voltage is determined by the chemical poten-
tial difference of guest ions (Li or Na in most cases) in the cathode and anode.
The chemical potential of a guest ion is the partial derivative of the free
energy of the material with respect to the concentration of the guest ion. The
open-circuit voltage at intercalation level x is obtained as follows:
Vx
x
()
()
=−
−
cathod
node
(6.9)
where A represents the guest ion,
is the chemical potential of the ...