Homogeneous polymer-ionic solvate electrolyte with weak dipole-dipole interaction enabling long cycling pouch lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid polymer electrolytes (SPEs) are crucial for high-voltage lithium metal batteries.
• Strong dipole-dipole interactions in SPEs hinder ionic conductivity enhancement.
• Existing SPEs face limitations in achieving high ionic conductivity for practical applications.

Purpose of the Study:

• To develop a strategy to overcome the ionic conductivity bottleneck in SPEs.
• To introduce a novel diluent, 1,1,2,2-Tetrafluoroethyl-2,2,3,3-Tetrafluoropropylether (TTE), to regulate interactions within polymer electrolytes.
• To enhance the performance and stability of lithium metal batteries using modified SPEs.

Main Methods:

• Synthesized polymer-ionic solvate electrolytes (TPISEs) incorporating the TTE diluent.
• Investigated the effect of TTE on dipole-dipole interactions and ionic solvate distribution.
• Characterized ionic conductivity, interfacial properties, and electrochemical performance of the TPISEs in Li metal batteries.

Main Results:

• TTE significantly reduced dipole-dipole interactions, promoting homogeneous ionic solvate distribution and a continuous ion-conducting network.
• Achieved an enhanced ionic conductivity of 1.27×10^-3 S cm^-1 at 25 °C.
• Demonstrated a stable lithium/electrolyte interface with a 190-fold increase in exchange current density and excellent cycling stability (-30 °C to 60 °C).

Conclusions:

• The TTE diluent effectively regulates dipole-dipole interactions, overcoming a key limitation in SPEs.
• TPISEs with TTE exhibit superior ionic conductivity and interfacial stability, enabling high-performance lithium metal batteries.
• This study presents a promising design strategy for advanced solid-state batteries with enhanced energy density and cycle life.