LITHIUM SECONDARY BATTERY

Provided is a lithium secondary battery including a positive electrode layer composed of a cobalt-containing lithium complex oxide sintered body, a negative electrode layer composed of a titanium-containing sintered body, a ceramic separator interposed between the positive electrode layer and the negative electrode layer and containing MgO, an electrolytic solution with which the positive electrode layer, the negative electrode layer, and the ceramic separator are impregnated, and an exterior body including a closed space, the closed space accommodating the positive electrode layer, the negative electrode layer, the ceramic separator, and the electrolytic solution, wherein the positive electrode layer, the ceramic separator, and the negative electrode layer are bonded together, and the interface between the negative electrode layer and the ceramic separator has a larger roughness than the interface between the positive electrode layer and the ceramic separator.