Abstract: A positive electrode of a lithium secondary battery includes a sheet-like positive electrode current collector having conductivity, and a positive electrode active material plate that is a plate-like ceramic sintered compact joined to the positive electrode current collector via a conductive joint layer. The positive electrode active material plate includes at least one active material plate element. This at least one active material plate element is joined to the positive electrode current collector. A main surface of the active material plate element that opposes the positive electrode current collector includes a joint region in which the conductive joint layer exists between the positive electrode current collector and the active material plate element and a non-joint region in which the conductive joint layer does not exist between the positive electrode current collector and the active material plate element. The non joint region is arranged around the joint region.

Abstract: In a lithium secondary cell, a positive electrode includes a sheet-like positive current collector having conductivity and a positive active material plate that is a plate-like ceramic sintered body containing a lithium composite oxide. The positive active material plate is bonded to the positive current collector via a conductive bonding layer. The positive active material plate is penetrated by the conductive bonding layer through a surface of the positive active material plate facing the positive current collector. A penetration depth of the conductive bonding layer in the positive active material plate with respect to a direction of superposition is 3% or more and 80% or less of a thickness of the positive active material plate.

Abstract: A positive electrode of a lithium secondary battery includes a sheet-like positive electrode current collector having conductivity, and a positive electrode active material plate that is a plate-like ceramic sintered compact joined to the positive electrode current collector via a conductive joint layer. The positive electrode active material plate includes at least one active material plate element. This at least one active material plate element is joined to the positive electrode current collector. A main surface of the active material plate element that opposes the positive electrode current collector includes a joint region in which the conductive joint layer exists between the positive electrode current collector and the active material plate element and a non-joint region in which the conductive joint layer does not exist between the positive electrode current collector and the active material plate element. The non joint region is arranged around the joint region.