SECONDARY BATTERY

Provided is a secondary battery that can sufficiently suppress a leakage current even when conductive foreign matter passes through a separator to cause a minute short-circuit. The secondary battery according to an aspect of the present disclosure comprises: a positive electrode; a negative electrode; and a separator interposed between the positive electrode and the negative electrode, wherein each of the positive electrode and the negative electrode has a current collector and a mixed material layer formed on the surface of the current collector. At least one of the positive electrode and the negative electrode has a semiconductor layer formed substantially over the entire surface of the mixed material layer and having a higher resistance than the mixed material layer.