Modulating Conductivity and Porosity of Interlayer for Long-Cycling All-Solid-State Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sulfide-based all-solid-state lithium metal batteries (ASSLMBs) offer high energy density and safety but face challenges with lithium metal anodes.
• Key issues include dendrite formation, solid electrolyte decomposition, and unstable interfaces, hindering practical application.

Purpose of the Study:

• To develop and evaluate a novel gradient interlayer for lithium metal anodes in ASSLMBs.
• To address dendrite growth, solid electrolyte degradation, and improve lithium deposition uniformity.

Main Methods:

• Fabrication of a triple Si/Carbon nanotube (CNT) interlayer with engineered gradients in conductivity and porosity.
• Characterization of the interlayer's structure and electrochemical performance in half-cell and full-cell configurations.
• Testing with an Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ cathode for long-term cycling and rate capability.

Main Results:

• The gradient interlayer achieved 95.1% initial Coulombic efficiency and 99.9% cycling efficiency over 150 cycles in half-cells.
• Full cells demonstrated 85.2% capacity retention after 500 cycles and stability up to 1800 cycles.
• Excellent rate capabilities were observed: 85.2% at 2C, 76.3% at 5C, and 65.2% at 10C.

Conclusions:

• Gradient-structured interlayers are highly effective in suppressing dendrite growth and SE degradation in ASSLMBs.
• The developed Si/CNT interlayer facilitates uniform lithium deposition, leading to enhanced battery performance and longevity.
• This strategy paves the way for high-energy-density, long-cycling ASSLMBs.