LITHIUM SECONDARY BATTERY

Provided is a lithium secondary battery including a positive electrode layer composed of a lithium complex oxide sintered body, a negative electrode layer composed of a titanium-containing sintered body, a ceramic separator interposed therebetween, an electrolytic solution, and an exterior body including a closed space, which accommodates 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, a ratio C/A of a capacity C of the positive electrode layer to a capacity A of the negative electrode layer is 1.03 to 2.30, a ratio Tc/Ta of a thickness Tc of the positive electrode layer to a thickness Ta of the negative electrode layer is 0.50 to 2.00, the thickness Tc is 50 to 1000 μm, and the thickness Ta is 50 to 1200 μm.