All Solid State Battery with Soft Carbon-TiSi₂ Multilayer Structure for Optimized LiSi Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal and silicon anodes are crucial for high-energy-density all-solid-state batteries (ASSBs).
• Lithium dendrite growth and silicon volume expansion cause short-circuiting and capacity fading, hindering ASSB applications.
• Advanced anode designs are needed to overcome these limitations in ASSBs.

Purpose of the Study:

• To design and investigate a novel three-layer structured anode for ASSBs.
• To address challenges of lithium dendrite growth and silicon volume expansion in ASSBs.
• To enhance the electrochemical performance and cycle life of ASSBs.

Main Methods:

• Fabrication of a Si-TiSi2-LPSCl/soft carbon/Li (ST5-SC-Li) three-layer structured anode.
• Utilizing TiSi2 for rigid support and LPSCl for plastic deformation to manage silicon expansion.
• Constructing an ion-electron dual network for enhanced conductivity and ion transport.
• Incorporating a soft carbon (SC) layer to absorb stress and inhibit dendrite penetration.
• Employing a Li metal layer for dynamic compensation of irreversible capacity loss.

Main Results:

• The ST5-SC-Li anode effectively restricts anisotropic silicon expansion and mitigates volume changes.
• A continuous ionic channel and ion-electron dual network were formed, improving conductivity.
• The soft carbon layer successfully absorbed expansion stress and inhibited dendrite penetration.
• LCO/LPSCl/ST5-SC-Li ASSBs demonstrated an ultra-long cycle life of 64,000 cycles at 10C with >100% capacity retention.
• A high reversible areal capacity of 19.6 mAh cm-2 was achieved at 0.1C under high loading.

Conclusions:

• The developed three-layer structured anode significantly enhances the stability and performance of ASSBs.
• The multi-layer design effectively suppresses lithium dendrites and silicon volume expansion.
• This anode architecture offers a promising pathway for realizing high-energy-density and long-lasting ASSBs.