All-solid secondary battery and method of manufacturing the same

An all-solid secondary battery comprising:

• a cathode layer comprising a cathode active material layer;
• an anode layer;
• and
• a solid electrolyte layer between the cathode layer and the anode layer, the solid electrolyte layer comprising a solid electrolyte,
• wherein the anode layer comprises
• an anode current collector,
• a first anode active material layer in contact with the solid electrolyte layer, and
• a second anode active material layer between the anode current collector and the first anode active material layer,
• wherein the first anode active material layer is a lithium-containing first metal layer comprising lithium and a first metal,
• wherein the second anode active material layer comprises
• a carbon-containing anode active material, or
• a carbon-containing anode active material and a second metal, and
• wherein
• the solid electrolyte layer has an outermost surface adjacent to the first anode active material layer and an opposite second surface adjacent to the cathode layer, the solid electrolyte layer having a porous portion extending from the outermost surface in a direction towards the opposite second surface, and the porous portion having a porosity of 1 percent to 20 percent, and
• the first metal of the lithium-containing first metal layer is present in a pore of the porous portion of the solid electrolyte layer and has a particle size of about 10 nanometers to about 900 nanometers,
• wherein, the solid electrolyte layer comprises lithium, and a content of lithium of the solid electrolyte layer in an area within a 1 micrometer distance from the outermost surface of the solid electrolyte layer adjacent to the first anode active material layer is depleted by about 5 atomic percent to about 20 atomic percent, based on a total lithium content of the solid electrolyte.