Mediating Solid Electrolyte Interphase Formation Kinetics on SiO_x Anodes Using Proton Acceptors.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Silicon anodes offer high energy density but face challenges with volume expansion and unstable solid electrolyte interphase (SEI) formation.
• Current electrolyte additives for SEI stabilization exhibit suboptimal decomposition kinetics, competing with other electrolyte components and leading to inefficient SEI structures.

Purpose of the Study:

• To improve the stability of the solid electrolyte interphase (SEI) on silicon anodes.
• To enhance the electrochemical performance of silicon-based batteries by optimizing additive utilization.

Main Methods:

• Introduced a proton acceptor to react with fluoroethylene carbonate (FEC), a common electrolyte additive.
• Generated an intermediate that lowers the reduction kinetic barrier for LiF formation.
• Investigated the effect of the intermediate on SEI composition, structure, and mechanical properties.

Main Results:

• Accelerated LiF formation and enriched LiF in the inner SEI layer, creating a more stable SEI structure.
• The modified SEI exhibited improved mechanical stability and lithium-ion conductivity, effectively accommodating silicon anode volume changes.
• Achieved superior electrochemical performance compared to conventional methods, demonstrating enhanced silicon anode utilization.

Conclusions:

• The intermediate-based strategy significantly enhances the efficiency of commercial additives like FEC.
• This approach offers a practical and effective direction for designing advanced electrolytes for high-performance silicon anodes.
• The improved SEI stability and performance pave the way for next-generation high-energy-density batteries.