A high efficiency electrolyte enables robust inorganic-organic solid electrolyte interfaces for fast Li metal anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-rate lithium metal anodes are crucial for fast-charging batteries.
• Concentration gradients and unstable passivation layers hinder Li metal anode performance at high current densities, leading to low Coulombic efficiency.

Purpose of the Study:

• To develop a stable, high-rate lithium metal anode using a novel electrolyte.
• To improve the Coulombic efficiency and cycling stability of lithium metal anodes under high current densities.

Main Methods:

• Investigated a concentrated dual-salts electrolyte composed of LiFSI-LiNO3 in DOL (1,2-dimethoxyethane).
• Evaluated the passivation behavior of fresh lithium deposition and the flexibility of organic layers formed by the electrolyte.
• Tested the cycling performance and Coulombic efficiency of the lithium metal anode at a high current density of 8.0 mA cm⁻².

Main Results:

• The LiFSI-LiNO3/DOL electrolyte effectively passivates fresh lithium deposition due to sufficient Li salts.
• 1,2-dimethoxyethane (DOL) promotes the formation of flexible organic layers, accommodating lithium metal volume changes during cycling.
• The lithium metal anode demonstrated stable cycling over 240 cycles with an average Coulombic efficiency of 99.14% at 8.0 mA cm⁻².

Conclusions:

• The concentrated dual-salts LiFSI-LiNO3/DOL electrolyte significantly enhances the high-rate performance and stability of lithium metal anodes.
• This electrolyte design addresses key challenges in lithium metal battery development, paving the way for faster charging capabilities.