Switching Electrolyte Interfacial Model to Engineer Solid Electrolyte Interface for Fast Charging and...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• The solid electrolyte interphase (SEI) is critical for metal-ion battery performance, but its formation mechanism at the molecular level remains unclear.
• Understanding SEI formation is key to developing advanced battery electrolytes.

Purpose of the Study:

• To develop a new strategy for tuning SEI properties by switching electrolytes.
• To elucidate the molecular mechanisms of SEI formation in different electrolyte systems.
• To enable high-rate capabilities and wide-temperature operation in lithium-ion batteries.

Main Methods:

• Pre-forming a unique, thinner SEI on graphite electrodes using an ether-based electrolyte.
• Utilizing a carbonate-based electrolyte in the subsequent step for enhanced performance.
• Developing a molecular interfacial model to analyze Li+-solvent-anion complexes and SEI formation differences.

Main Results:

• Achieved extremely high-rate capabilities in graphite | LiNi0.6Co0.2Mn0.2O2 (NCM622) batteries.
• Demonstrated the feasibility of fast-charging and wide-temperature battery operation.
• Interpreted the enhanced rate performance through molecular-level understanding of SEI formation.

Conclusions:

• The electrolyte switching strategy successfully combines advantages of different electrolytes for improved battery performance.
• This approach provides a universal pathway for designing stable and versatile SEI layers.
• The study opens new avenues for engineering advanced battery systems.