Abstract: An anode capable of relaxing internal stress and thereby preventing deformation and a battery using it are provided. An anode provided with an anode active material layer is formed on an anode current collector. The anode active material layer has active material particles containing silicon (Si) as an element, and at least some of the active material particles contain a polymer component in the particle.

Abstract: A battery capable of improving cycle characteristics is provided. An anode contains Si as an element. Where the Li insertion amount per unit area when the anode is fully charged is A, the Li amount capable of being electronically inserted per unit area of the anode is B, and the maximum utilization ratio C % is (A/B)×100, the maximum utilization ratio C % is in the range from 35% to 85%. The surface roughness Ra value of the anode current collector is 0.2 ?m or more.