Cathode material and battery

1. A cathode material, comprising:

particles of a cathode active material comprising a lithium nickel-cobalt-manganese oxide;

a coating layer comprising a first solid electrolyte material forming a coating surrounding a surface of the particles of the cathode active material; and

particles of a second solid electrolyte material,

wherein the first solid electrolyte material is represented by Li 2 MgX 4 , Li 2 FeX 4 , Li(Al a Ga b In c )X 4 , Li 3 (Al a Ga b In c )X 6 , where 0≤a≤1, 0≤b≤1, 0≤c≤1, a+b+c=1, or the following composition formula (1):

Li α M β X 6   Formula (1)

where 2.5≤α≤3,

1≤β≤1.1,

M includes at least one element selected from the group consisting of Mg, Al, Ca, Sc, Ti, Zn, Ga, Sr, Y, Zr, Nb, Sn, Ba, Hf, Ta, Bi, B, Si, Ge, As, Sb, and Te, and

X includes at least one element selected from the group consisting of Cl and Br,

wherein the second solid electrolyte material is represented by Li 3 YX′ 6 , Li 2 MgX′ 4 , Li 2 FeX′ 4 , Li(Al a′ Ga b′ In c′ )X′ 4 , Li 3 (Al a′ Ga b′ In c′ )X′ 6 , where 0≤a′≤1, 0≤b′≤1, 0≤c′≤1, a′+b′+c′=1, and X′ includes I and at least one element selected from the group consisting of Cl and Br, and

wherein the particles of the cathode active material and the particles of the second solid electrolyte material are separated by the coating formed by the first solid electrolyte material and are not in direct contact with each other.

2. The cathode material according to claim 1 , wherein M includes yttrium.

3. The cathode material according to claim 1 , wherein X′ includes Cl and Br.

4. A battery, comprising:

a cathode including the cathode material according to claim 1 ;

an anode; and

an electrolyte layer provided between the cathode and the anode,

wherein the electrolyte layer comprises at least one sulfide solid electrolyte material selected from the group consisting of Li 2 S—P 2 S 5 , Li 2 S—SiS 2 , Li 2 S—B 2 S 3 , Li 2 S—GeS 2 , Li 3.25 Ge 0.25 P 0.75 S 4 , and Li 10 GeP 2 S 12 .