Suppressing lithium dendrite formation by slowing its desolvation kinetics

Area of Science:

• Electrochemistry
• Materials Science
• Battery Technology

Background:

• Lithium metal batteries offer high energy density but suffer from dendrite formation, leading to capacity fade and safety concerns.
• Dendrite growth during lithium electrodeposition is a major obstacle for commercializing advanced battery systems.

Purpose of the Study:

• To investigate the use of tetraethylene glycol dimethyl ether (TEGDME) as a complementary solvent to suppress lithium dendrite formation.
• To elucidate the mechanism by which TEGDME influences Li+ desolvation and electrodeposition kinetics.

Main Methods:

• Density functional theory (DFT) calculations were employed to study the coordination interactions between Li+ and various solvents.
• Raman spectroscopy was utilized to experimentally verify the coordination strength and solvation shell structure.
• Electrochemical testing of Li|Li symmetric cells was performed to evaluate cycling stability and morphology.

Main Results:

• TEGDME exhibits stronger coordination with Li+ compared to traditional solvents like DME and DOL.
• This enhanced coordination increases the desolvation activation energy of Li+, slowing down lithium electrodeposition kinetics.
• Uniform lithium electrodeposition morphology was observed, and Li|Li symmetric cells demonstrated stable cycling for over 500 hours.

Conclusions:

• TEGDME effectively suppresses lithium dendrite formation by controlling the electrochemical reaction rate.
• The findings suggest a novel strategy for enhancing the safety and longevity of lithium metal batteries through solvent engineering.