Anion-Complementary Soft Solvation Electrolytes Stabilizing Dual Interfaces for High-Voltage Lithium Metal Batteries...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium metal batteries (LMBs) suffer from interfacial instability, including lithium dendrite growth and electrolyte decomposition.
• Conventional electrolytes struggle to stabilize both lithium metal anodes and high-voltage cathodes due to competing reactions.

Purpose of the Study:

• To develop a novel electrolyte that addresses the interfacial challenges in LMBs.
• To enable simultaneous stabilization of lithium metal anodes and high-voltage cathodes.

Main Methods:

• A softly solvating electrolyte was designed using 1,3-dioxane (1,3-DX) and dual salts (LiFSI/LiPF6).
• Anion-complementary coordination was employed to separate interfacial functions of FSI- and PF6-.
• Spectroscopic techniques (Raman, 17O NMR) and microscopy (SEM, TEM) were used for characterization.

Main Results:

• The electrolyte formed a LiF-rich solid-electrolyte interphase (SEI) on the anode and a thin cathode-electrolyte interphase (CEI) on the NCM523 cathode.
• Li||NCM523 cells demonstrated over 80% capacity retention after 100 cycles at 4.3 V with high Coulombic efficiency (>99.0%).
• Excellent low-temperature performance was observed, retaining 36.9% capacity at -30 °C.

Conclusions:

• The developed electrolyte effectively reconciles bulk ion transport with dual-electrode interfacial requirements through an anion-synergistic design.
• This strategy enhances the stability, cycle life, and low-temperature performance of lithium metal batteries.