Amorphous Matrix-Integrated Si Anodes with Enhanced Elasticity and Conductivity for Li-Ion and All-Solid-State Li-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon (Si) is a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity.
• However, Si anodes suffer from large volume expansion during lithiation/delithiation, leading to poor cycling stability.
• Developing robust matrices to encapsulate Si and buffer volume changes is crucial for high-performance LIBs and all-solid-state LIBs (ASSLIBs).

Purpose of the Study:

• To develop high-performance anode materials for LIBs and ASSLIBs using amorphous matrix-integrated Si nanocomposites.
• To investigate the role of an amorphous Ni3ZnSi2 matrix and a dual-matrix approach with graphite in enhancing Si anode performance.
• To evaluate the electrochemical properties of Si/a-Ni3ZnSi2/G nanocomposites in both conventional LIBs and ASSLIBs.

Main Methods:

• Amorphous Ni3ZnSi2 was synthesized and used as an elastic and conductive matrix for Si nanocrystallites via high-energy milling.
• Dual-matrix Si/a-Ni3ZnSi2/G nanocomposites were fabricated by incorporating a graphite framework.
• Electrochemical performance was tested in coin cells (LIBs) and full cells with NCM811 cathodes and Li6PS5Cl solid electrolytes (ASSLIBs).

Main Results:

• The Si/a-Ni3ZnSi2/G nanocomposite anode demonstrated uniform encapsulation of Si nanocrystallites within the amorphous matrix, providing elastic recovery and buffering volume changes.
• The dual-matrix structure synergistically enhanced charge transport and mechanical stability, leading to high initial Coulombic efficiency, high-rate capability, and long-term cycling stability.
• LIB full cells achieved an energy density of 377.7 Wh kg-1, while ASSLIBs exceeded 300 Wh kg-1 with stable performance across various temperatures and current densities.

Conclusions:

• Amorphous matrix-integrated Si nanocomposites, particularly the dual-matrix Si/a-Ni3ZnSi2/G, are highly effective anode materials for next-generation LIBs and ASSLIBs.
• The developed materials offer a scalable solution for high-energy-density energy storage devices.
• The findings underscore the potential of advanced Si-based anodes for future battery technologies.