Asymmetric Surface Charge Engineering Regulates Solvation Structure and Ionic Conductivity in Confined Polymer...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Solid polymer electrolytes (SPEs) are safer alternatives to liquid electrolytes for lithium-metal batteries.
• Low ionic conductivity and lithium-ion transference limit SPE performance.
• Nanoporous confinement enhances ion transport, but molecular mechanisms are unclear.

Purpose of the Study:

• Investigate the impact of nanopore surface charge distribution and modification on ion transport in confined SPEs.
• Clarify molecular-level mechanisms governing lithium-ion dynamics influenced by nanopore electrostatics.
• Provide design principles for optimizing SPEs in nanoporous structures.

Main Methods:

• Utilized comprehensive molecular dynamics simulations.
• Systematically studied poly(ethylene oxide)/LiTFSI electrolytes confined within nanopores.
• Analyzed effects of surface charge distribution and electrostatic modification fractions.

Main Results:

• Charged nanopore walls generally decrease ionic conductivity due to lithium-ion adsorption.
• Asymmetric charge distributions enhance lithium-ion transference by impeding anion mobility.
• Nanopore polarity disrupts polymer coordination but creates alternative solvation sites, leading to a trade-off.

Conclusions:

• Careful balancing of electrostatic modification and charge asymmetry is crucial for optimizing ionic conductivity in nanoconfined SPEs.
• Molecular insights guide the engineering of advanced polymer electrolyte architectures.
• Findings support the development of next-generation lithium-metal batteries.