COMPOSITE ANODE ACTIVE MATERIAL FOR ALL-SOLID-STATE-BATTERY AND MANUFACTURING METHOD THEREOF

An embodiment composite negative electrode active material for an all-solid-state battery includes a negative electrode active material including a silicon-based active material and a coating layer including a solid electrolyte and coating a portion of a surface of the negative electrode active material, wherein a ratio (E/T) of a Young's modulus (E) of the solid electrolyte to a thickness (T) of the coating layer satisfies 0.02