Synergistic solid-liquid hybrid electrolyte for cycle-stable and high-efficiency Li-CuCl₂ batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-energy lithium-ion batteries are crucial for modern technology.
• Copper chloride (CuCl2) cathodes offer high theoretical energy density but suffer from capacity decay due to material dissolution and copper ion crossover.
• Existing electrolytes struggle to mitigate these degradation issues effectively.

Purpose of the Study:

• To develop a novel hybrid electrolyte system for CuCl2 conversion cathodes.
• To address the challenges of active material dissolution and copper species migration.
• To enhance the cycling stability and energy density of lithium-ion batteries.

Main Methods:

• Integration of a solvation-tuned liquid electrolyte (8 M LiFSI/DME) with a Li1.5Al0.5Ge1.5(PO4)3 (LAGP) ceramic electrolyte.
• Utilizing the hybrid electrolyte to confine solvent molecules and create a physical barrier against CuCl2 dissolution.
• Employing the LAGP ceramic as an ion-selective membrane to inhibit copper ion migration.

Main Results:

• The hybrid electrolyte effectively suppressed CuCl2 dissolution and copper species crossover.
• Achieved remarkable cycling stability with 77.9% capacity retention over 400 cycles at 0.5C.
• Demonstrated a high energy efficiency of 95.8% and a practical energy density of 806.6 W h kg−1.

Conclusions:

• The solid-liquid hybrid electrolyte is a viable strategy for improving the performance of conversion-type metal chloride cathodes.
• This approach significantly enhances cycling stability and energy density in lithium-ion batteries.
• The developed system offers a promising solution for next-generation high-energy storage devices.