A protected anode, an electrochemical device including the same, and a method of preparing the electrochemical device. The protected anode may include: an anode layer; and a protective layer including an oxide represented by Formula 1, on the anode layer:

##STRFormula 1##

In Formula 1, A is at least one of Ge, Sb, Bi, Se, Sn, or Pb; M is at least one of In, Tl, Sb, Bi, S, Se, Te, or Po; A and M are different from each other; and 0<x<100 and 0<y<100.

The present invention concerns new lithium rare earth halides that may be used as solid electrolytes or in electrochemical devices. The invention also refers to wet and dry processes for the synthesis of such lithium rare earth halides and lithium rare earth halides susceptible to be obtained by these processes.

A negative electrode with little degradation is provided. Alternatively, a novel negative electrode is provided. A secondary battery includes a positive electrode and a negative electrode, and the negative electrode includes a solvent containing fluorine, a current collector, a negative electrode active material, and graphene. The negative electrode further includes a solid electrolyte material and the solid electrolyte material is an oxide. The negative electrode active material may contain fluorine. The secondary battery may include a plurality of electrolytes different from each other. The negative electrode active material is, for example, a material containing one or more elements selected from silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, and indium.

A solid electrolyte contains a compound that has a crystal phase having an argyrodite-type crystal structure and that is represented by Li.sub.aPS.sub.bX.sub.c, where X is at least one elemental halogen, a represents a number of 3.0 or more and 6.0 or less, b represents a number of 3.5 or more and 4.8 or less, and c represents a number of 0.1 or more and 3.0 or less. The proportion of the crystal phase with an argyrodite-type structure relative to all crystal phases constituting the solid electrolyte is 97.0 wt % or more. The compound has a lattice strain of less than 0.10%. The solid electrolyte preferably exhibits a lithium ion conductivity of 4.0 mS/cm or more.

One aspect of the present invention is a solid electrolyte which has a crystal structure attributable to a space group F-43m and contains lithium, phosphorus, sulfur, and an element A, in which the element A is a metal element having an ionic radius of more than 59 pm and 120 pm or less in 4-fold coordination and 6-fold coordination in an ion crystal.

A positive electrode material of the present disclosure includes: a positive electrode active material; and a first solid electrolyte material coating at least partially a surface of the positive electrode active material, wherein the first solid electrolyte material includes Li, Ti, M1, and F, and the M1 is at least one element selected from the group consisting of Ca, Mg, Al, Y, and Zr.

A positive-electrode material according to the present disclosure includes a positive-electrode active material and a coating layer covering the positive-electrode active material, wherein the coating layer contains niobium and carbon, the positive-electrode active material and the coating layer constitute a coated active material, and the ratio Nb/C of the niobium content to the carbon content in a surface layer portion of the coated active material is 0.11 or more based on the atomic ratio.

The present disclosure relates to a solid electrolyte containing a halide-based nanocomposite, a method for preparing the same and an all-solid-state battery including the solid electrolyte. Halide-based nanocomposites were prepared by the mechanochemical reaction of a lithium oxide precursor, a lithium halide precursor, and a metal halide in order to improve the low ion conductivity and large interfacial resistance of the existing halide-based solid electrolyte. Furthermore, it is possible to provide superior atmospheric stability, improve ion conductivity through activation of interfacial conduction and, at the same time, significantly improve the interfacial stability with a sulfide-based solid electrolyte and high-voltage cycle stability.

Provided is a battery including a positive electrode including a first positive electrode layer and a second positive electrode layer; a negative electrode; and an electrolyte layer. The first positive electrode layer includes a first positive electrode active material, a first solid electrolyte material, and a coating material. The second positive electrode layer includes a second positive electrode active material and the first solid electrolyte material. The first solid electrolyte material includes lithium, at least one kind selected from the group consisting of metalloid elements and metal elements other than lithium; and at least one kind selected from the group consisting of chlorine and bromine. The first solid electrolyte material does not include sulfur.

A lithium-ion conducting composite material includes a Li binary salt, a Li-ion conductor with a chemical composition of Li.sub.2−3x+y−zFe.sub.xO.sub.y(OH).sub.1−yCl.sub.1−z, and at least two of: a first inorganic compound with a chemical composition of (Fe.sub.1−xM1.sub.x)O.sub.1−y(OH).sub.yCl.sub.1−x; a second inorganic compound with a chemical composition of M2OX; and a defected doped inorganic compound with a chemical composition of (M3OX)′. The value of n is 1 or 2, x is greater than 0 and less than or equal to 0.25, and y is greater than or equal to 0 and less than or equal to 0.25. Also, M1 is at least one of Mg and Ca, M2 and M3 are each at least one of Fe, Al, Sc, La, and Y, and X is at least one of F, Cl, Br, and I.