To provide a secondary battery in which a side reaction does not easily occur at an interface between a positive electrode active material and a solid electrolyte, an interface between the positive electrode active material and a positive electrode current collector, or the like even when charge and discharge are repeated. In one embodiment of the present invention, a buffer layer or a protective layer is provided on a current collector surface or between a current collector layer and an active material layer to prevent deterioration such as oxidation of the current collector. As the buffer layer or the protective layer, it is possible to use a titanium compound such as titanium oxide, titanium oxide in which nitrogen is substituted for part of oxygen, titanium nitride, titanium nitride in which oxygen is substituted for part of nitrogen, or titanium oxynitride (TiO.sub.xN.sub.y, where 0<x<2 and 0<y<1). Titanium nitride is particularly preferable because it has high conductivity and has a high capability of inhibiting oxidation.

The solid electrolyte material of the present disclosure includes Li, Ca, Y, Sm, X, O, and H, wherein, X is at least one selected from the group consisting of F, Cl, Br, and I; and the molar ratio of O to the sum of Y and Sm is greater than 0 and less than 0.32.

The solid electrolyte material of the present disclosure includes Li, Ca, Y, Sm, X, O, and H, wherein, X is at least one selected from the group consisting of F, Cl, Br, and I; and the molar ratio of O to the sum of Y and Sm is greater than 0 and less than 0.32.

The solid electrolyte material consists essentially of Li, Ti, M, and F. Here, M is at least one selected from the group consisting of Al and Y.

The solid electrolyte material consists essentially of Li, Ti, M, and F. Here, M is at least one selected from the group consisting of Al and Y.

An all-solid secondary battery includes: a cathode layer; an anode layer; and a solid electrolyte between the cathode layer and the anode layer, wherein the anode layer includes an anode current collector and a first anode active material layer on the anode current collector, the first anode active material layer includes a modified ordered mesoporous carbon, and an oxygen content of a surface of the modified ordered mesoporous carbon is about 3 atomic percent to about 10 atomic percent, based on a total content of the surface, when determined by an X-ray photoelectron spectroscopy spectrum of the surface of the modified ordered mesoporous carbon.

A method of treating the surface of a positive electrode active material that is capable of inhibiting a reaction at the interface between a sulfide-based solid electrolyte and the positive electrode active material. A positive electrode active material particle for sulfide-based all-solid-state batteries, the surface of which is reformed, using the method and a sulfide-based all-solid-state battery, the charge/discharge characteristics of which are improved, including the same are also disclosed. The positive electrode active material particle for sulfide-based all-solid-state batteries manufactured using a dry-type method exhibits larger capacity than a positive electrode active material particle for sulfide-based all-solid-state batteries manufactured through a conventional wet-type process. In addition, the manufacturing process is simplified, and the amount of byproducts is reduced.

A method of treating the surface of a positive electrode active material that is capable of inhibiting a reaction at the interface between a sulfide-based solid electrolyte and the positive electrode active material. A positive electrode active material particle for sulfide-based all-solid-state batteries, the surface of which is reformed, using the method and a sulfide-based all-solid-state battery, the charge/discharge characteristics of which are improved, including the same are also disclosed. The positive electrode active material particle for sulfide-based all-solid-state batteries manufactured using a dry-type method exhibits larger capacity than a positive electrode active material particle for sulfide-based all-solid-state batteries manufactured through a conventional wet-type process. In addition, the manufacturing process is simplified, and the amount of byproducts is reduced.

The present invention relates to a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries. The a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries includes a compound with an argyrodite-type crystal structure represented by the following Formula 1:
Li.sub.aPS.sub.bN.sub.cX.sub.d  [Formula 1] wherein 6≤a≤7, 3≤b≤6, 0≤c≤1, 0≤d≤2, and each X is the same or different halogen atom selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I).

The present invention relates to a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries. The a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries includes a compound with an argyrodite-type crystal structure represented by the following Formula 1:
Li.sub.aPS.sub.bN.sub.cX.sub.d  [Formula 1] wherein 6≤a≤7, 3≤b≤6, 0≤c≤1, 0≤d≤2, and each X is the same or different halogen atom selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I).