<p>The increasing demand for high-energy-density lithium-ion batteries necessitates the development of an alternative anode material that can surpass the limitations of the graphite anode. Among the potential candidates, germanium (Ge) is an interesting anode material for lithium-ion batteries owing to its high theoretical capacity and higher lithium-ion diffusivity. This study investigates the lithiation mechanism, electrochemical performance, and structural integrity of Ge-based composite as anode for an all-solid-state lithium-ion battery (ASSLIB). A composite electrode consisting of germanium (Ge), electronically conductive acetylene black (AB), and ionically conductive lithium borohydride (LiBH₄) was synthesized by a simple high-energy ball-milling approach. The electrochemical performance evaluation in a half-cell configuration revealed that the Ge-LiBH₄-AB electrode exhibits excellent electrochemical performance with a reversible lithiation capacity of 1424.7&#xa0;mAh&#xa0;g⁻¹ with an initial coulombic efficiency of 93.25% operated at a c-rate of 0.1&#xa0;C. The Li⁺ ion storage mechanism was further studied via ex situ x-ray diffraction, indicating the formation of highly lithiated Li₁₅Ge₄ phase. Furthermore, morphological and interfacial properties of the pristine and cycled electrode were determined by scanning electron microscopy and electrochemical impedance spectroscopy techniques. Overall, this work explores the feasibility of Ge as a viable anode candidate for an all-solid-state lithium-ion battery, highlighting its potential toward the development of safer and high-energy-density storage system.</p>