Electrochemical Stability Window (ECW) Calculation

Goal

To determine the intrinsic electrochemical stability window (ECW) of a material, specifically bounding the reduction ($V_{\text{red}}$) and oxidation ($V_{\text{ox}}$) potentials against a mobile working ion (e.g., Li/Li+), using a standard zero-Kelvin phase diagram.

This explicitly implements the standard thermodynamic approach for solid electrolytes defined in: Zhu, Y., He, X. & Mo, Y. "Origin of Outstanding Stability in the Lithium Solid Electrolyte Materials: Insights from Thermodynamic Analyses Based on First-Principles Calculations". ACS Appl. Mater. Interfaces 7, 23685–23693 (2015).

[!TIP] Coupling with Stability: ECW calculation relies entirely on the same generic computed energies and PhaseDiagram used for determining $E_{hull}$. You can uniquely combine this with the mat-stability skill to calculate both intrinsic thermodynamic stability and electrochemical stability in the same step using the same unified convex hull.

Methodology

The electrochemical stability window of a phase represents the voltage range over which it is thermodynamically stable against reduction by (e.g., lithiation) or oxidation (e.g., delithiation) of the target ion.

In pymatgen, this exact analytical bounding is extracted using PhaseDiagram.get_transition_chempots(mobile_element).