One aspect of the present invention is a solid electrolyte containing lithium, phosphorus, sulfur, halogen, and tin as constituent elements and having a crystal structure.

A proton conductor of the present disclosure includes a compound represented by the chemical formula BaZr.sub.(1-x-y)Yb.sub.xSc.sub.yO.sub.3-δ. The chemical formula satisfies 0<x<0.5, 0 <y<0.5, (x+y)<0.5, and 0<δ<0.5.

An electrode material of the present disclosure is an electrode material that includes a compound represented by the chemical formula BaZr.sub.1-x-yM.sub.xCo.sub.yO.sub.3-δ. M is In or Yb, and the chemical formula satisfies 0<x<1, 0<y<1, 0<(x+y)<1, and 0<δ<1. A membrane electrode assembly of the present disclosure includes a first electrode including the electrode material, and an electrolyte membrane provided on a first main surface of the first electrode.

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 oxygen and lithium, the positive-electrode active material and the coating layer constitute a coated active material, and the ratio Li/O of the lithium content to the oxygen content in a surface layer portion of the coated active material is 0.26 or less based on the atomic ratio.

A covered positive electrode active material includes a particulate positive electrode active material and a solid electrolyte that covers a surface of the positive electrode active material. The solid electrolyte forms a covering layer. The covering layer is formed such that recessed portions of the surface of the positive electrode active material are filled with the solid electrolyte. Protruding portions of the surface of the positive electrode active material are exposed on a surface of the covered positive electrode active material. A degree of unevenness of a group of particles of the positive electrode active material is defined as ζ.sub.1, a degree of unevenness of a group of particles of the covered positive electrode active material is defined as ζ.sub.2, and a degree of change in unevenness R defined by formula (2) below is greater than or equal to 1.1.

R=ζ.sub.2/ζ.sub.1   (2)

The production method of the present disclosure includes: heat-treating a material mixture containing LiA, YB.sub.3, GdC.sub.3, and CaD.sub.2 in an inert gas atmosphere. A, B, C, and D are each independently at least one selected from the group consisting of F, Cl, Br, and I. In the heat-treating, the material mixture is heat-treated at higher than or equal to 200° C. and lower than or equal to 700° C.

Several variations of synthetic carbon materials are disclosed. The materials can assume a variety of properties, including high electrical conductivity. The materials also can have favorable structural and mechanical properties. They can form gas impenetrable barriers, form insulating structures, and can have unique optical properties.

The present invention relates to an anode active material, a method of manufacturing the anode active material, and an anode and a secondary battery including the anode active material, the anode active material including secondary carbon particles formed by flocculation of a plurality of primary carbon particles having an average particle diameter (D.sub.50) in a range from 5 to 200 nm, wherein the secondary carbon particles have an average particle diameter (D.sub.50) in a range from 0.5 to 20 μm.

A positive-electrode active material contains a compound that has a crystal structure belonging to a space group FM3-M and contains is represented by the composition formula (1) and an insulating compound,
Li.sub.xMe.sub.yO.sub.αF.sub.β  (1)
wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr, and the following conditions are satisfied.
1.7≤x≤2.2
0.8≤y≤1.3
1≤α≤2.5
0.5≤β≤2

The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to the process, and to the uses of the composite material, especially as a precursor for the synthesis of electrochemically-active materials, electrode or active anode material.