|
specific interfacial area, m−1 |
|
activity of species i, unitless |
A |
area, m2 |
Ac |
cell or electrode area, m2 |
Ar |
Archimedes number, unitless |
b |
Tafel slope, V per decade |
B |
Debye constant for solvent, (kg/mol)½ m−1 |
c |
total concentration or salt concentration, mol m−3 |
c |
speed of light, 2.99792 × 108 m s−1 |
ci |
concentration of species i, mol m−3 |
C |
capacitance, F |
Cd |
differential capacitance, F |
CDL |
double layer capacitance per unit area, F m−2 |
Cp |
battery capacity offset, unitless |
|
distance, m |
|
hydraulic diameter, m |
|
molecular diffusivity of species i, m2·s−1 |
E |
energy for battery or double layer capacitor, J or W·h |
E |
elastic modulus, Pa |
Ea |
activation energy, J/mol |
Eg |
energy gap, eV |
f |
frequency, Hz |
fi |
fugacity of species i, Pa |
F |
Faraday's constant, 96485 C per equivalent |
Fx |
component of force, N |
|
acceleration of gravity, m s−2 |
G |
Gibbs energy, J mol−1 |
G |
conductance, Ω−1 |
Gr |
Grashof number, unitless |
h |
thickness, gap in electrolysis cells, m |
h |
Planck's constant, J-s |
H |
Enthalpy, J mol−1 |
i, i |
current density, A m−2 |
|
current, A |
|
exchange current density, A·m−2 |
|
photon flux, s−1·m−2 |
Ji |
molar flux of species i, mol m−2 s−1 |
ka, kc |
anodic and cathodic reaction rate constants |
kc |
mass transfer coefficient, m s−1 |
k |
thermal conductivity, W·m−1·K−1 |
K |
equilibrium constant, unitless |
L |
characteristic length, m |
Lp |
diffusion length, m |
m |
mass, kg |
m |
molality, mol kg−1 |
|
mass flow, kg s−1 |
Mi |
molecular weight, g·mol−1 or kg·mol−1 |
n |
number of electrons transferred |
n |
number density of electrons, m−3 |
ni |
number of moles of species i, mol |
ni |
number density of electrons in intrinsic semiconductor, m−3 |
NAV |
Avogadro's number |
NA |
number density of acceptor atoms, m−3 |
ND |
number density of donor atoms, m−3 |
Ni |
molar flux of species i relative to stationary coordinates, mol m−2 s−1 |
p |
pressure, Pa |
p |
number density of holes, m−3 |
P |
power, W |
P |
perimeter, m |
q |
fundamental charge, 1.602 × 10−19 C |
q |
charge per unit surface area, C·m−2 |
|
rate of heat generation, W |
Q |
charge, C or A·h |
r |
radius, m |
R |
universal gas constant, 8.314 J mol−1K−1 |
RΩ |
ohmic resistance, Ω or Ω-m2 |
Re |
Reynolds number, unitless |
|
homogeneous reaction rate, mol m−3s−1 |
|
stoichiometric coefficient, unitless |
S |
electrical conductance, S |
S |
entropy, J mol−1K−1 |
Sh |
Sherwood number, unitless |
Sc |
Schmidt number, unitless |
t |
time, s |
|
transference number of species i, unitless |
T |
Temperature, K, or °C |
U |
equilibrium potential, V |
ui |
mobility of ion, m2 mol J−1s−1 |
v |
velocity, m s−1 |
V |
electric potential or voltage, V |
vs |
superficial velocity, m s−1 |
|
volumetric flowrate m3 s−1 |
|
volume, m3 |
W |
work, J |
W |
width of depletion layer, m |
w |
molar flowrate, mol s−1 |
Wa |
Wagner number, unitless |
xi |
mole fraction of species i in condensed phase, unitless |
yi |
mole fraction of species i in gas phase, unitless |
zi |
charge number |