Anode layer for all-solid secondary battery, all-solid secondary battery including the same, and method of manufacturing all-solid secondary battery

1. An anode layer for all-solid secondary batteries, the anode layer comprising:

an anode current collector; and

a first anode active material layer on the anode current collector,

wherein the first anode active material layer includes a metal-carbon composite including a metal, carbon, and a polyol, and the metal includes silver, zinc, tin, or a combination thereof, and

wherein, in the metal-carbon composite, a content of the metal is about 3 wt % to about 25 wt %, a content of the carbon is about 55 wt % to about 95 wt %, and a content of the polyol is about 2 wt % to about 40 wt %, based on a total weight of the metal-carbon composite.

2. The anode layer as claimed in claim 1 , wherein the metal-carbon composite has:

a bulk density of about 0.1 g/cm 3 to about 0.5 g/cm 3 , and

a BET specific surface area of about 40 m 2 /g to 60 m 2 /g.

3. The anode layer as claimed in claim 1 , wherein, in an infrared spectroscopic analysis of the metal-carbon composite, one absorption peak appears at a wave number of about 750 cm −1 to about 1,200 cm −1 , and another absorption peak appears at a wave number of about 3,250 cm −1 to about 3,500 cm −1 .

4. The anode layer as claimed in claim 1 , wherein, in a thermogravimetric analysis of the metal-carbon composite, a weight loss is about 3 wt % to about 30 wt % at about 50° C. to about 150° C.

5. The anode layer as claimed in claim 1 , wherein the anode layer has a porosity of 30% or less.

6. The anode layer as claimed in claim 1 , wherein the polyol includes ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, poly(ethylene glycol), propanediol, butanediol, pentanediol, hexanediol, glycerol, or a combination thereof.

7. The anode layer as claimed in claim 1 , further comprising a metal or metalloid thin film between the anode current collector and the first anode active material layer.

8. The anode layer as claimed in claim 7 , wherein:

the metal or metalloid thin film includes gold (Au), silver (Ag), magnesium (Mg), zinc (Zn), silicon (Si), tin (Sn), platinum (Pt), palladium (Pd), aluminum (Al), bismuth (Bi), or a combination thereof, and

the metal or metalloid thin film has a thickness of about 1 nm to about 800 nm.

9. The anode layer as claimed in claim 1 , further comprising a second anode active material layer,

wherein:

the second anode active material layer includes a metal, a metalloid element, or a combination thereof, the metal or metalloid element being capable of forming an alloy with lithium, or

the second anode active material layer is a metal layer including lithium or a lithium alloy.

10. An all-solid secondary battery, comprising:

a cathode layer;

an anode layer; and

a solid electrolyte layer between the cathode layer and the anode layer,

wherein the anode layer is the anode layer as claimed in claim 1 .

11. The all-solid secondary battery as claimed in claim 10 , wherein:

the anode layer further includes a second anode active material on the first anode active material layer or between the anode current collector and the first anode active material layer, and

the second anode active material layer includes lithium or a lithium alloy.

12. The all-solid secondary battery as claimed in claim 10 , wherein the anode layer further includes a carbon layer between the first anode active material layer and the solid electrolyte layer.

13. The all-solid secondary battery as claimed in claim 10 , wherein a solid electrolyte included in the solid electrolyte layer is a sulfide solid electrolyte.

14. The all-solid secondary battery as claimed in claim 13 , wherein the sulfide solid electrolyte includes Li 2 S-P 2 S 5 , Li 2 S-P 2 S 5 -LiX, in which X is a halogen element, Li 2 S-P 2 S 5 -Li 2 O, Li 2 S-P 2 S 5 -Li 2 O-LiI, Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-B 2 S 3 , Li 2 S-P 2 S 5 -Z m S n , in which m and n are each a positive number, and Z is Ge, Zn, or Ga, Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li p MO q , in which p and q are each a positive number, and M is P, Si, Ge, B, Al, Ga, or In, Li 7-x PS 6-x Cl x , in which 0≤x≤2, Li 7-x PS 6-x Br x , in which 0≤x≤2, or Li 7-x PS 6-x I x , in which 0≤x≤2.

15. The all-solid secondary battery as claimed in claim 13 , wherein the sulfide solid electrolyte is an argyrodite solid electrolyte including Li 6 PS 5 Cl, Li 6 PS 5 Br, or Li 6 PS 5 I.

16. The anode layer as claimed in claim 1 , wherein, in the metal-carbon composite, the metal includes silver.

17. A method of manufacturing an all-solid secondary battery, the method comprising:

providing an anode layer including an anode current collector and a first anode active material layer;

providing a cathode layer;

providing a solid electrolyte layer between the anode layer and the cathode layer to prepare a laminate; and

pressing the laminate,

wherein the first anode active material layer includes a metal-carbon composite including a metal, carbon, and a polyol, and the metal includes silver, zinc, tin, or a combination thereof, and

wherein, in the metal-carbon composite, a content of the metal is about 3 wt % to about 25 wt %, a content of the carbon is about 55 wt % to about 95 wt %, and a content of the polyol is about 2 wt % to about 40 wt %, based on a total weight of the metal-carbon composite.

18. The method as claimed in claim 17 , wherein providing the anode layer includes applying a composition including the metal-carbon composite, a binder, and a solvent onto an anode current collector and drying to prepare the anode layer including the first anode active material layer including the anode current collector and a metal-carbon composite.

19. The method as claimed in claim 18 , wherein the metal-carbon composite is prepared by:

mixing a carbon material, a metal precursor, a polyol, and a solvent to obtain a mixture; and applying light or heat to the mixture.

20. The method as claimed in claim 17 , wherein, in the metal-carbon composite, the metal includes silver.