Electrode structure and secondary battery

A secondary battery comprising a positive electrode, a negative electrode, and a separator, wherein

• the positive electrode and the negative electrode each include a current collector and an active material-containing layer supported on at least one surface of the current collector,
• the separator includes an organic fiber layer facing the active material-containing layer of at least one of the positive electrode and the negative electrode,
• the organic fiber layer includes an organic fiber having an aspect ratio (V1/H1) in a cross section which is 0.97 or less, the cross section intersecting with a length direction of the organic fiber, the organic fiber having the aspect ratio (V1/H1) is in contact with a surface of the active material-containing layer having a roughness higher than an arithmetic mean surface roughness Ra of the active material-containing layer in the cross section,
• the V1 denotes a length parallel to a thickness direction of the active material-containing layer, and the H1 denotes a length horizontal to an in-plane direction of the active material-containing layer.