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

Abstract

Amorphous matrix-integrated Si nanocomposites were developed as high-performance anodes for Li-ion batteries (LIBs) and all-solid-state Li-ion batteries (ASSLIBs). Amorphous Ni₃ZnSi₂ was employed as the elastic and conductive matrix because its unique crystal structure readily undergoes amorphization during high-energy milling, yielding a Si/a-Ni₃ZnSi₂ nanocomposite in which Si nanocrystallites are uniformly encapsulated within the amorphous Ni₃ZnSi₂ matrix. The amorphous Ni₃ZnSi₂ matrix provides elastic recovery, high ionic/electronic conductivity, and effective buffering against large volume changes, thereby preserving electrode integrity during cycling. Incorporating a conductive graphite framework further produced dual-matrix Si/a-Ni₃ZnSi₂/G nanocomposites, where the amorphous Ni₃ZnSi₂ and graphite frameworks synergistically enhance charge transport and mitigate mechanical stress. The Si/a-Ni₃ZnSi₂/G anode exhibited high initial Coulombic efficiency, high-rate capability, and long-term cycling stability in both LIBs and ASSLIBs. In LIB full cells comprising a Si/a-Ni₃ZnSi₂/G anode and a LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode, an energy density of 377.7 Wh kg^-1 was achieved with stable cycling performance and high-rate capability. In ASSLIB configurations with Li₆PS₅Cl solid electrolytes, the full cell delivered energy densities exceeding 300 Wh kg^-1 while maintaining electrochemical stability across wide ranges of temperature and current density. These findings highlight the scalability and potential applicability of Si/a-Ni₃ZnSi₂/G nanocomposites as next-generation anode materials for both LIBs and ASSLIBs.