A positive electrode material in one aspect of the present disclosure includes: a positive electrode active material; and a first solid electrolyte that covers the surface of the positive electrode active material. The first solid electrolyte contains Li, M1, O, and X1. M1 is at least one element selected from the group consisting of Nb and Ta. X1 is at least one element selected from the group consisting of Cl, Br, and I.

A conductive powder for an internal electrode includes a metal particle and a graphene oxide disposed on at least a portion of a surface of the metal particle. A content of the graphene oxide is less than 1.0 weight percent, based on a weight of the metal particle.

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 cathode material, containing a crystal with a superlattice structure, is provided. A chemical formula of the crystal is xLi.sub.2MO.sub.3.(1-x)LiNi.sub.aCo.sub.bMn.sub.(1-a-b)O.sub.2, where 0<x≤0.1, 0.8≤a<1, b≤0.1, and M is selected from one or more of Mn, Co, and Ni. A preparation method of the cathode material and a battery or a capacitor containing the cathode material are also provided.

A cathode material, containing a crystal with a superlattice structure, is provided. A chemical formula of the crystal is xLi.sub.2MO.sub.3.(1-x)LiNi.sub.aCo.sub.bMn.sub.(1-a-b)O.sub.2, where 0<x≤0.1, 0.8≤a<1, b≤0.1, and M is selected from one or more of Mn, Co, and Ni. A preparation method of the cathode material and a battery or a capacitor containing the cathode material are also provided.

A solid electrolyte is composed of a compound represented by the general formula Li.sub.xM.sub.2(PO.sub.4).sub.z where M represents at least one element having a valence of one to four, x represents a number that satisfies 1.003≤x≤1.900, and z represents a number that satisfies 3.001≤z≤3.200.

The present invention aims to provide a lithium ion-conducting oxide capable of providing a solid electrolyte with an excellent ion conductivity, and a solid electrolyte, a sintered body, an electrode material or an electrode and an all-solid-state battery using the same. The lithium ion-conducting oxide of the present invention includes at least lithium, tantalum, phosphorus, silicon, and oxygen as constituent elements, has a peak in a region of −20.0 ppm to 0.0 ppm on the solid-state .sup.31P-NMR spectrum, and has a peak in a range of −80.0 ppm to −100.0 ppm on the solid-state .sup.29Si-NMR spectrum.

A solid electrolyte material according to the present disclosure is represented by the following composition formula (1), Li.sub.aAl.sub.bO.sub.cX.sub.d . . . Formula (1) where values a, b, c, and d are each greater than 0, and X is at least one selected from the group consisting of CI and Br. A battery according to the present disclosure includes a positive electrode, a negative electrode and an electrolyte layer disposed between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer includes the solid electrolyte material according to the present disclosure.

An electrochromic device according to an embodiment includes a first transparent conductive layer, an ion storage layer, an electrolyte layer, an electrochromic layer, and a second transparent conductive layer. The electrolyte layer includes a tantalum atom. The electrochromic layer includes a tungsten atom. The ion storage layer includes an iridium atom and a tantalum atom. The ion storage layer is hydrogenated in bleached state and the electrochromic device has a transmittance of 64.1% or more in bleached state. A difference between the transmittance of the electrochromic device in bleached state and the transmittance of the electrochromic device in colored state is 8.4% or more.