Negative electrode for all-solid secondary battery, all-solid secondary battery including negative electrode, and method of preparing all-solid secondary battery

A negative electrode-solid electrolyte sub-assembly for an all-solid secondary battery, the sub-assembly comprising:

• a negative electrode current collector;
• a first negative active material layer on the current collector;
• an interlayer on the first negative active material layer;
• and
• a solid electrolyte on the interlayer and opposite the first negative active material layer,
• wherein the interlayer comprises a composite comprising a first metal material and a lithium ion conductor, wherein the first metal material comprises a first metal, an alloy comprising the first metal and lithium, a compound comprising the first metal and lithium, or a combination thereof,
• wherein the first negative active material layer comprises a carbonaceous negative active material, and optionally a first negative active material comprising a second metal, a metalloid, or a combination thereof, and
• wherein the negative electrode-solid electrolyte sub-assembly further comprises a second negative active material layer between the negative electrode current collector and the first negative active material layer, and the second negative active material layer comprises a third metal material, and the third metal material comprises at least one metal of lithium, a third metal, a lithium alloy, or a combination thereof.

A method of preparing an all-solid secondary battery, the method comprising:

• providing a positive electrode;
• disposing a solid electrolyte on the positive electrode;
• disposing an interlayer on the solid electrolyte opposite the positive electrode;
• disposing a first negative active material layer on the interlayer, the first negative active material layer comprising
• a carbonaceous negative active material, and
• optionally a first negative active material comprising a second metal, a metalloid, or a combination thereof;
• and
• disposing a current collector on the first negative active material layer opposite the interlayer to prepare the all-solid secondary battery.

An all-solid secondary battery comprising:

• a positive electrode;
• and
• a negative electrode-solid electrolyte sub-assembly;
• wherein the solid electrolyte is between the positive electrode and the negative electrode,
• wherein the negative electrode-solid electrolyte sub-assembly comprises
• a negative electrode current collector,
• a first negative active material layer on the current collector,
• an interlayer on the first negative active material layer, and
• a solid electrolyte on the interlayer and opposite the first negative active material layer,
• wherein the interlayer comprises a composite comprising a first metal material and a lithium ion conductor, wherein the first metal material comprises a first metal, an alloy comprising the first metal and lithium, a compound comprising the first metal and lithium, or a combination thereof,
• wherein the first negative active material layer comprises
• a carbonaceous negative active material, and
• optionally a first negative active material comprising a second metal, a metalloid, or a combination thereof, and
• wherein the negative electrode-solid electrolyte sub-assembly further comprises a second negative active material layer between the negative electrode current collector and the first negative active material layer.