Negative electrode and battery

Abstract

A negative electrode 10 is used in an electrode group having a wound structure. The negative electrode 10 is provided with a negative electrode current collector 11 having a first surface 11a positioned on the winding inner circumferential side and a second surface 11b positioned on the winding outer circumferential side, a first negative electrode mixture layer 12 disposed on the first surface 11a, and a second negative electrode mixture layer 13 disposed on the second surface 11b. The first negative electrode mixture layer 12 and the second negative electrode mixture layer 13 each contain, as negative electrode active materials, a silicon-containing material and graphite. When the expansion coefficient during charging of the first negative electrode mixture layer 12 is A1, and the expansion coefficient during charging of the second negative electrode mixture layer 13 is A2, A1 and A2 satisfy relational expression (1) in at least a portion of the negative electrode 10.　(1): A1 < A2

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