def from_steps(cls,
step1,
step2,
normalization_els,
framework_formula=None):
"""
Creates a ConversionVoltagePair from two steps in the element profile
from a PD analysis.
Args:
step1: Starting step
step2: Ending step
normalization_els: Elements to normalize the reaction by. To
ensure correct capacities.
"""
working_ion_entry = step1["element_reference"]
working_ion = working_ion_entry.composition.elements[0].symbol
working_ion_valence = max(Element(working_ion).oxidation_states)
voltage = (-step1["chempot"] +
working_ion_entry.energy_per_atom) / working_ion_valence
mAh = ((step2["evolution"] - step1["evolution"]) *
Charge(1, "e").to("C") * Time(1, "s").to("h") * N_A * 1000 *
working_ion_valence)
licomp = Composition(working_ion)
prev_rxn = step1["reaction"]
reactants = {
comp: abs(prev_rxn.get_coeff(comp))
for comp in prev_rxn.products if comp != licomp
}
curr_rxn = step2["reaction"]
products = {
comp: abs(curr_rxn.get_coeff(comp))
for comp in curr_rxn.products if comp != licomp
}
reactants[licomp] = step2["evolution"] - step1["evolution"]
rxn = BalancedReaction(reactants, products)
for el, amt in normalization_els.items():
if rxn.get_el_amount(el) > 1e-6:
rxn.normalize_to_element(el, amt)
break
prev_mass_dischg = (sum([
prev_rxn.all_comp[i].weight * abs(prev_rxn.coeffs[i])
for i in range(len(prev_rxn.all_comp))
]) / 2)
vol_charge = sum([
abs(prev_rxn.get_coeff(e.composition)) * e.structure.volume
for e in step1["entries"]
if e.composition.reduced_formula != working_ion
])
mass_discharge = (sum([
curr_rxn.all_comp[i].weight * abs(curr_rxn.coeffs[i])
for i in range(len(curr_rxn.all_comp))
]) / 2)
mass_charge = prev_mass_dischg
mass_discharge = mass_discharge
vol_discharge = sum([
abs(curr_rxn.get_coeff(e.composition)) * e.structure.volume
for e in step2["entries"]
if e.composition.reduced_formula != working_ion
])
totalcomp = Composition({})
for comp in prev_rxn.products:
if comp.reduced_formula != working_ion:
totalcomp += comp * abs(prev_rxn.get_coeff(comp))
frac_charge = totalcomp.get_atomic_fraction(Element(working_ion))
totalcomp = Composition({})
for comp in curr_rxn.products:
if comp.reduced_formula != working_ion:
totalcomp += comp * abs(curr_rxn.get_coeff(comp))
frac_discharge = totalcomp.get_atomic_fraction(Element(working_ion))
rxn = rxn
entries_charge = step2["entries"]
entries_discharge = step1["entries"]
return cls(
rxn=rxn,
voltage=voltage,
mAh=mAh,
vol_charge=vol_charge,
vol_discharge=vol_discharge,
mass_charge=mass_charge,
mass_discharge=mass_discharge,
frac_charge=frac_charge,
frac_discharge=frac_discharge,
entries_charge=entries_charge,
entries_discharge=entries_discharge,
working_ion_entry=working_ion_entry,
_framework_formula=framework_formula,
)
def __init__(self, entry1, entry2, working_ion_entry):
#initialize some internal variables
working_element = working_ion_entry.composition.elements[0]
entry_charge = entry1
entry_discharge = entry2
if entry_charge.composition.get_atomic_fraction(working_element) \
> entry2.composition.get_atomic_fraction(working_element):
(entry_charge, entry_discharge) = (entry_discharge, entry_charge)
comp_charge = entry_charge.composition
comp_discharge = entry_discharge.composition
ion_sym = working_element.symbol
frame_charge_comp = Composition({
el: comp_charge[el]
for el in comp_charge if el.symbol != ion_sym
})
frame_discharge_comp = Composition({
el: comp_discharge[el]
for el in comp_discharge if el.symbol != ion_sym
})
#Data validation
#check that the ion is just a single element
if not working_ion_entry.composition.is_element:
raise ValueError("VoltagePair: The working ion specified must be "
"an element")
#check that at least one of the entries contains the working element
if not comp_charge.get_atomic_fraction(working_element) > 0 and \
not comp_discharge.get_atomic_fraction(working_element) > 0:
raise ValueError("VoltagePair: The working ion must be present in "
"one of the entries")
#check that the entries do not contain the same amount of the workin
#element
if comp_charge.get_atomic_fraction(working_element) == \
comp_discharge.get_atomic_fraction(working_element):
raise ValueError("VoltagePair: The working ion atomic percentage "
"cannot be the same in both the entries")
#check that the frameworks of the entries are equivalent
if not frame_charge_comp.reduced_formula == \
frame_discharge_comp.reduced_formula:
raise ValueError("VoltagePair: the specified entries must have the"
" same compositional framework")
#Initialize normalization factors, charged and discharged entries
valence_list = Element(ion_sym).oxidation_states
working_ion_valence = max(valence_list)
(self.framework,
norm_charge) = frame_charge_comp.get_reduced_composition_and_factor()
norm_discharge = \
frame_discharge_comp.get_reduced_composition_and_factor()[1]
self._working_ion_entry = working_ion_entry
#Initialize normalized properties
self._vol_charge = entry_charge.structure.volume / norm_charge
self._vol_discharge = entry_discharge.structure.volume / norm_discharge
comp_charge = entry_charge.composition
comp_discharge = entry_discharge.composition
self._mass_charge = comp_charge.weight / norm_charge
self._mass_discharge = comp_discharge.weight / norm_discharge
self._num_ions_transferred = \
(comp_discharge[working_element] / norm_discharge) \
- (comp_charge[working_element] / norm_charge)
self._voltage = \
(((entry_charge.energy / norm_charge) -
(entry_discharge.energy / norm_discharge)) / \
self._num_ions_transferred + working_ion_entry.energy_per_atom) / working_ion_valence
self._mAh = self._num_ions_transferred * Charge(1, "e").to("C") * \
Time(1, "s").to("h") * AVOGADROS_CONST * 1000 * working_ion_valence
#Step 4: add (optional) hull and muO2 data
self.decomp_e_charge = \
entry_charge.data.get("decomposition_energy", None)
self.decomp_e_discharge = \
entry_discharge.data.get("decomposition_energy", None)
self.muO2_charge = entry_charge.data.get("muO2", None)
self.muO2_discharge = entry_discharge.data.get("muO2", None)
self.entry_charge = entry_charge
self.entry_discharge = entry_discharge
self.normalization_charge = norm_charge
self.normalization_discharge = norm_discharge
self._frac_charge = comp_charge.get_atomic_fraction(working_element)
self._frac_discharge = \
comp_discharge.get_atomic_fraction(working_element)
def from_entries(cls, entry1, entry2, working_ion_entry):
"""
Args:
entry1: Entry corresponding to one of the entries in the voltage step.
entry2: Entry corresponding to the other entry in the voltage step.
working_ion_entry: A single ComputedEntry or PDEntry representing
the element that carries charge across the battery, e.g. Li.
"""
# initialize some internal variables
working_element = working_ion_entry.composition.elements[0]
entry_charge = entry1
entry_discharge = entry2
if entry_charge.composition.get_atomic_fraction(
working_element) > entry2.composition.get_atomic_fraction(
working_element):
(entry_charge, entry_discharge) = (entry_discharge, entry_charge)
comp_charge = entry_charge.composition
comp_discharge = entry_discharge.composition
ion_sym = working_element.symbol
frame_charge_comp = Composition({
el: comp_charge[el]
for el in comp_charge if el.symbol != ion_sym
})
frame_discharge_comp = Composition({
el: comp_discharge[el]
for el in comp_discharge if el.symbol != ion_sym
})
# Data validation
# check that the ion is just a single element
if not working_ion_entry.composition.is_element:
raise ValueError(
"VoltagePair: The working ion specified must be an element")
# check that at least one of the entries contains the working element
if (not comp_charge.get_atomic_fraction(working_element) > 0 and
not comp_discharge.get_atomic_fraction(working_element) > 0):
raise ValueError(
"VoltagePair: The working ion must be present in one of the entries"
)
# check that the entries do not contain the same amount of the workin
# element
if comp_charge.get_atomic_fraction(
working_element) == comp_discharge.get_atomic_fraction(
working_element):
raise ValueError(
"VoltagePair: The working ion atomic percentage cannot be the same in both the entries"
)
# check that the frameworks of the entries are equivalent
if not frame_charge_comp.reduced_formula == frame_discharge_comp.reduced_formula:
raise ValueError(
"VoltagePair: the specified entries must have the same compositional framework"
)
# Initialize normalization factors, charged and discharged entries
valence_list = Element(ion_sym).oxidation_states
working_ion_valence = abs(max(valence_list))
(
framework,
norm_charge,
) = frame_charge_comp.get_reduced_composition_and_factor()
norm_discharge = frame_discharge_comp.get_reduced_composition_and_factor(
)[1]
# Initialize normalized properties
if hasattr(entry_charge, "structure"):
_vol_charge = entry_charge.structure.volume / norm_charge
else:
_vol_charge = entry_charge.data.get("volume")
if hasattr(entry_discharge, "structure"):
_vol_discharge = entry_discharge.structure.volume / norm_discharge
else:
_vol_discharge = entry_discharge.data.get("volume")
comp_charge = entry_charge.composition
comp_discharge = entry_discharge.composition
_mass_charge = comp_charge.weight / norm_charge
_mass_discharge = comp_discharge.weight / norm_discharge
_num_ions_transferred = (
comp_discharge[working_element] /
norm_discharge) - (comp_charge[working_element] / norm_charge)
_voltage = (
((entry_charge.energy / norm_charge) -
(entry_discharge.energy / norm_discharge)) / _num_ions_transferred
+ working_ion_entry.energy_per_atom) / working_ion_valence
_mAh = _num_ions_transferred * Charge(1, "e").to("C") * Time(
1, "s").to("h") * N_A * 1000 * working_ion_valence
_frac_charge = comp_charge.get_atomic_fraction(working_element)
_frac_discharge = comp_discharge.get_atomic_fraction(working_element)
vpair = InsertionVoltagePair( # pylint: disable=E1123
voltage=_voltage,
mAh=_mAh,
mass_charge=_mass_charge,
mass_discharge=_mass_discharge,
vol_charge=_vol_charge,
vol_discharge=_vol_discharge,
frac_charge=_frac_charge,
frac_discharge=_frac_discharge,
working_ion_entry=working_ion_entry,
entry_charge=entry_charge,
entry_discharge=entry_discharge,
framework_formula=framework.reduced_formula,
)
# Step 4: add (optional) hull and muO2 data
vpair.decomp_e_charge = entry_charge.data.get("decomposition_energy",
None)
vpair.decomp_e_discharge = entry_discharge.data.get(
"decomposition_energy", None)
vpair.muO2_charge = entry_charge.data.get("muO2", None)
vpair.muO2_discharge = entry_discharge.data.get("muO2", None)
return vpair