Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1-SnP₂S₁₂

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Enhancing ionic conductivity in solid electrolytes is crucial for advanced battery technologies.
• Current strategies often focus on crystal structure modification or ion stoichiometry.
• The solid-electrolyte inductive effect, a less-explored approach, proposes modulating chemical bonding to improve ion diffusion.

Purpose of the Study:

• To provide direct evidence for the solid-electrolyte inductive effect in superionic lithium-ion conductors.
• To investigate how chemical bonding changes influence lithium-ion diffusion pathways and energy landscapes.
• To demonstrate the practical application of the solid-electrolyte inductive effect for tuning ionic conductivity.

Main Methods:

• Investigated the archetypal superionic conductor Li10Ge1-xSnxP2S12.
• Utilized density functional theory (DFT) calculations to model Ge → Sn substitution.
• Analyzed changes in {Ge,Sn}-S bonding, S2- ion charge density, and Li+ ion potential energy surfaces.

Main Results:

• Ge → Sn substitution weakens {Ge,Sn}-S bonds and increases S2- charge density.
• Charge redistribution alters the Li+ substructure, strengthening Li+-anion interactions.
• DFT calculations confirm the inductive effect occurs without geometric host framework changes.

Conclusions:

• The study provides direct evidence supporting the measurable solid-electrolyte inductive effect.
• Modulating chemical bonding through substitution is a viable strategy for enhancing ionic conductivity.
• This approach offers a practical method for tuning ion diffusion in superionic lithium-ion conductors.