Stabilized Electrode/Electrolyte Interphase by a Saturated Ionic Liquid Electrolyte for High-Voltage...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Nonaqueous electrolytes are critical for high-performance lithium-ion batteries but pose technical challenges.
• Enabling high-voltage cathodes and high-capacity anodes requires advanced electrolyte solutions.

Purpose of the Study:

• To develop a novel ionic liquid electrolyte for advanced lithium-ion batteries.
• To investigate the electrolyte's performance with high-voltage cathodes and high-capacity anodes.

Main Methods:

• Utilized a saturated piperidinum bis(fluorosulfonyl)imide ionic liquid with LiFSI salt.
• Conducted cycling performance tests on NMC532/Si-graphite full cells between 4.6 and 3.0 V.
• Employed spectroscopic/microscopic analysis and molecular dynamics (MD) simulations.

Main Results:

• The ionic liquid electrolyte demonstrated support for high-voltage cathode redox reactions.
• Exceptional kinetic stability was observed on the lithiated anode, improving cycling performance.
• Formation of a stable solid-electrolyte interphase on both electrodes was confirmed.
• A unique solvation structure with a deadlocked coordination network was identified.

Conclusions:

• The developed ionic liquid electrolyte overcomes nonaqueous electrolyte limitations in high-performance lithium-ion batteries.
• The electrolyte's stability and unique solvation structure prevent transition metal dissolution, enhancing battery longevity.
• This research offers a promising pathway for next-generation lithium-ion battery electrolytes.