pymatgen.apps.battery.conversion_battery module

This module contains the classes to build a ConversionElectrode.

class ConversionElectrode(voltage_pairs: Tuple[pymatgen.apps.battery.battery_abc.AbstractVoltagePair], working_ion_entry: pymatgen.entries.computed_entries.ComputedEntry, framework_formula: str, initial_comp_formula: str)

Bases: pymatgen.apps.battery.battery_abc.AbstractElectrode

Class representing a ConversionElectrode, since it is dataclass this object can be constructed for the attributes. However, it is usually easier to construct a ConversionElectrode using one of the classmethods constructors provided.

Attribute:

voltage_pairs: The voltage pairs making up the Conversion Electrode. working_ion_entry: A single ComputedEntry or PDEntry

representing the element that carries charge across the battery, e.g. Li.

initial_comp_formula: Starting composition for ConversionElectrode represented

as a string/formula.

as_dict_summary(**kwargs)

classmethod from_composition_and_entries(comp, entries_in_chemsys, working_ion_symbol='Li', allow_unstable=False)

Convenience constructor to make a ConversionElectrode from a composition and all entries in a chemical system.

Parameters

• comp – Starting composition for ConversionElectrode, e.g., Composition(“FeF3”)

• entries_in_chemsys – Sequence containing all entries in a chemical system. E.g., all Li-Fe-F containing entries.

• working_ion_symbol – Element symbol of working ion. Defaults to Li.

• allow_unstable – If True, allow any composition to be used as the starting point of a conversion voltage curve, this is useful for comparing with insertion electrodes

classmethod from_composition_and_pd(comp, pd, working_ion_symbol='Li', allow_unstable=False)

Convenience constructor to make a ConversionElectrode from a composition and a phase diagram.

Parameters

• comp – Starting composition for ConversionElectrode, e.g., Composition(“FeF3”)

• pd – A PhaseDiagram of the relevant system (e.g., Li-Fe-F)

• working_ion_symbol – Element symbol of working ion. Defaults to Li.

• allow_unstable – Allow compositions that are unstable

get_sub_electrodes(adjacent_only=True)

If this electrode contains multiple voltage steps, then it is possible to use only a subset of the voltage steps to define other electrodes. For example, an LiTiO2 electrode might contain three subelectrodes: [LiTiO2 –> TiO2, LiTiO2 –> Li0.5TiO2, Li0.5TiO2 –> TiO2] This method can be used to return all the subelectrodes with some options

Parameters

adjacent_only – Only return electrodes from compounds that are adjacent on the convex hull, i.e. no electrodes returned will have multiple voltage steps if this is set true

Returns

A list of ConversionElectrode objects

get_summary_dict(print_subelectrodes=True) → Dict

Generate a summary dict. Populates the summary dict with the basic information from the parent method then populates more information. Since the parent method calls self.get_summary_dict(print_subelectrodes=True) for the subelectrodes. The current methode will be called from within super().get_summary_dict.

Parameters

print_subelectrodes – Also print data on all the possible subelectrodes.

Returns

A summary of this electrode”s properties in dict format.

property initial_comp

The pymatgen Composition representation of the initial composition

initial_comp_formula: str

is_super_electrode(conversion_electrode)

Checks if a particular conversion electrode is a sub electrode of the current electrode. Starting from a more lithiated state may result in a subelectrode that is essentially on the same path. For example, a ConversionElectrode formed by starting from an FePO4 composition would be a super_electrode of a ConversionElectrode formed from an LiFePO4 composition.

class ConversionVoltagePair(voltage: float, mAh: float, mass_charge: float, mass_discharge: float, vol_charge: float, vol_discharge: float, frac_charge: float, frac_discharge: float, working_ion_entry: pymatgen.entries.computed_entries.ComputedEntry, framework_formula: str, rxn: pymatgen.analysis.reaction_calculator.BalancedReaction, entries_charge: Iterable[pymatgen.entries.computed_entries.ComputedEntry], entries_discharge: Iterable[pymatgen.entries.computed_entries.ComputedEntry])

Bases: pymatgen.apps.battery.battery_abc.AbstractVoltagePair

A VoltagePair representing a Conversion Reaction with a defined voltage. Typically not initialized directly but rather used by ConversionElectrode. .. attribute:: rxn

type

BalancedReaction

BalancedReaction for the step

voltage: float

Voltage for the step

mAh: float

Capacity of the step

vol_charge: float

Volume of charged state

vol_discharge: float

Volume of discharged state

mass_charge: float

Mass of charged state

mass_discharge: float

Mass of discharged state

frac_charge: float

Fraction of working ion in the charged state

frac_discharge: float

Fraction of working ion in the discharged state

entries_charge: [ComputedEntry]

Entries in the charged state

entries_discharge: [ComputedEntry]

Entries in discharged state

working_ion_entry: ComputedEntry

Entry of the working ion.

entries_charge: Iterable[ComputedEntry]

entries_discharge: Iterable[ComputedEntry]

classmethod from_steps(step1, step2, normalization_els, framework_formula=None)

Creates a ConversionVoltagePair from two steps in the element profile from a PD analysis.

Parameters

• step1 – Starting step

• step2 – Ending step

• normalization_els – Elements to normalize the reaction by. To ensure correct capacities.

rxn: BalancedReaction