Tailoring the Salt Concentration in a Gel-Solid Polymer Electrolyte to Stabilize High-Voltage LiCoMnO₄ Cathode

Area of Science:

• Electrochemistry
• Materials Science
• Polymer Science

Background:

• Gel-solid polymer electrolytes (G-SPEs) offer potential advantages over conventional liquid electrolytes in battery technology.
• Understanding the influence of salt concentration on G-SPE properties is critical for optimizing their performance.

Purpose of the Study:

• To investigate the effect of lithium hexafluorophosphate (LiPF6) salt concentration on the electrochemical stability and ionic conductivity of G-SPEs.
• To evaluate the flammability and electrochemical performance of G-SPEs in battery configurations.

Main Methods:

• In-situ polymerization of liquid electrolyte on a solid polymer support to form G-SPEs.
• Electrochemical characterization (ionic conductivity measurements) and flammability tests.
• Half-cell and full-cell configurations using LiCoMnO4 cathodes and Li4Ti5O12 or Cu anodes.
• Post-mortem analysis including XRD, XPS, EDS, and SEM.

Main Results:

• Ionic conductivity of G-SPEs increased with LiPF6 concentration, reaching ≈10^-3 S cm^-1 at ambient temperature.
• G-SPEs demonstrated flame-retardant properties compared to liquid electrolytes.
• Stable electrochemical performance was observed in cells utilizing G-SPEs with varying salt concentrations.

Conclusions:

• Salt concentration is a key parameter for tuning the ionic conductivity and electrochemical stability of G-SPEs.
• G-SPEs exhibit promising characteristics for safer and high-performance battery applications.
• Further investigation into material degradation and electrolyte decomposition is warranted.