Abstract: The composite active material according to one aspect of the present disclosure includes an active material including Li, Ti, and O and a first solid electrolyte. The active material is a porous material having a plurality of pores. The first solid electrolyte includes Li, M, and X. M is at least one selected from the group consisting of metal elements and metalloid elements belonging to the 5th or 6th period. X is at least one selected from the group consisting of F, Cl, Br, and I. At least a part of the first solid electrolyte is present inside the plurality of pores.

Abstract: An electrode material includes an active material particle and a solid electrolyte particle. The solid electrolyte particle includes Li, M, and X, wherein M is at least one selected from the group consisting of metal elements excluding Li and metalloid elements, and X is at least one selected from the group consisting of F, Cl, Br, and I. The ratio R1 of the volume of the active material particle to the sum of the volume of the active material particle and the volume of the solid electrolyte particle is greater than or equal to 10% and less than 65% when expressed as percentage. The ratio R2 of the average particle diameter of the active material particle to the average particle diameter of the solid electrolyte particle is greater than or equal to 0.5 and less than or equal to 3.4.

Abstract: The electrode material according to one aspect of the present disclosure includes a first active material particle, a second active material particle, and a solid electrolyte. The first active material particle and the second active material particle each include Li, Ti, and O. The ratio of the average particle size of the second active material particle to the average particle size of the first active material particle is greater than or equal to 1.5 and less than or equal to 6.0. The battery according to one aspect of the present disclosure includes a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode. At least one selected from the group consisting of the positive electrode and the negative electrode includes the electrode material.

Abstract: A battery includes a positive-electrode layer, a negative-electrode layer, and an electrolyte layer between the positive-electrode layer and the negative-electrode layer, wherein the negative-electrode layer includes a negative-electrode active material and a first solid electrolyte, the electrolyte layer contains a second solid electrolyte, the negative-electrode active material contains Li, Ti, and O, the first solid electrolyte contains a crystalline phase assigned to a monoclinic crystal and contains Li, M1, and X1, wherein M1 denotes at least one of metal elements and metalloid elements other than Li, and X1 denotes at least one of F, Cl, Br, and I, and the second solid electrolyte contains a crystalline phase assigned to a trigonal crystal and contains Li, M2, and X2, wherein M2 denotes at least one of metal elements and metalloid elements other than Li, and X2 denotes at least one of F, Cl, Br, and I.

Abstract: A negative-electrode material includes a negative-electrode active material and a solid electrolyte. The negative-electrode active material contains Li, Ti, M1, and O, wherein M1 denotes at least one selected from the group consisting of metal elements and metalloid elements other than Li and Ti. The solid electrolyte contains Li, M2, and X, wherein M2 denotes at least one selected from the group consisting of metal elements and metalloid elements other than Li, and X denotes at least one selected from the group consisting of F, Cl, Br, and I.

Abstract: A catalyst includes a mesoporous material and catalytic metal particles supported at least within the mesoporous material and containing platinum and a metal different from platinum. The mesoporous material has mesopores with a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm3/g before supporting of the catalytic metal particles, and has an average particle size of greater than or equal to 200 nm. A molar ratio of the metal different from platinum and contained in the catalytic metal particles relative to all metals contained in the catalytic metal particles is greater than or equal to 0.25, and among the catalytic metal particles, a volume ratio of catalytic metal particles having a particle size of greater than or equal to 20 nm is less than or equal to 10%.

Abstract: An electrode catalyst of an electrochemical device according to the present disclosure is an electrode catalyst of an electrochemical device, the electrode catalyst including a mesoporous material; and catalyst metal particles supported at least in the mesoporous material. Before supporting the catalyst metal particles, the mesoporous material includes mesopores having a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm3/g, and number density of the catalyst metal particles supported in the mesopores is lower at an outer side of the mesoporous material than number density of the catalyst metal particles supported in the mesopores at an inner side thereof.

Abstract: An electrode catalyst for a fuel battery includes a mesoporous material and catalyst metal particles supported at least in the mesoporous material. In the electrode catalyst for a fuel battery, before supporting the catalyst metal particles, the mesoporous material has mesopores having a mode radius of greater than or equal to 1 nm and less than or equal to 25 nm and has a value of greater than 0.90, the value being determined by dividing a specific surface area S1-25 (m2/g) of the mesopores obtained by analyzing a nitrogen adsorption-desorption isotherm according to a BJH method, the mesopores having a radius of greater than or equal to 1 nm and less than or equal to 25 nm, by a BET specific surface area (m2/g) evaluated according to a BET method.

Abstract: A catalyst includes a mesoporous material and catalytic metal particles supported at least within the mesoporous material and containing platinum and a metal different from platinum. The mesoporous material has mesopores with a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm3/g before supporting of the catalytic metal particles, and has an average particle size of greater than or equal to 200 nm. A molar ratio of the metal different from platinum and contained in the catalytic metal particles relative to all metals contained in the catalytic metal particles is greater than or equal to 0.25, and among the catalytic metal particles, a volume ratio of catalytic metal particles having a particle size of greater than or equal to 20 nm is less than or equal to 10%.

Abstract: An electrode catalyst of an electrochemical device according to the present disclosure is an electrode catalyst of an electrochemical device, the electrode catalyst including a mesoporous material; and catalyst metal particles supported at least in the mesoporous material. Before supporting the catalyst metal particles, the mesoporous material includes mesopores having a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm3/g, and number density of the catalyst metal particles supported in the mesopores is lower at an outer side of the mesoporous material than number density of the catalyst metal particles supported in the mesopores at an inner side thereof.