Tailoring Li⁺ Local Coordination Environment of Solid Polymer Electrolytes to Boom Ionic Conductivity

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Low ionic conductivity in solid polymer electrolytes (SPEs) hinders their use in batteries.
• Previous research focused on reducing crystallinity, overlooking the influence of the lithium-ion (Li+) local coordination environment.

Purpose of the Study:

• To investigate the impact of the Li+ local coordination environment on SPE ionic conductivity.
• To develop a strategy for enhancing Li+ transport and ionic conductivity in SPEs.

Main Methods:

• Synthesized poly(vinylidene fluoride-co-hexafluoropropylene)-based SPEs.
• Incorporated d-cellobiose octaacetate to tune the Li+ coordination environment.
• Evaluated ionic conductivity and electrochemical performance in lithium metal symmetric and full batteries.

Main Results:

• d-cellobiose octaacetate modified the Li+ coordination, weakening interactions with anions and polymer chains.
• This modification increased charge carrier concentration and improved Li+ transport kinetics.
• Achieved significantly boosted ionic conductivity of SPEs at room temperature (25 °C).

Conclusions:

• The Li+ local coordination environment critically influences Li+ transport in SPEs.
• Tuning the coordination environment offers a promising strategy to enhance SPE ionic conductivity.
• Developed SPEs demonstrate improved electrochemical performance in lithium batteries.