| CPC H01M 4/386 (2013.01) [H01M 4/0471 (2013.01); H01M 4/366 (2013.01)] | 6 Claims |

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1. A method for producing an active material, the method comprising:
a preparing step of preparing a Zintl compound including Na, Si, and Al, and including at least a Zintl phase,
a Na removing step of removing the Na from the Zintl compound, and forming an intermediate including a silicon clathrate type crystal phase, and
an Al removing step, after the Na removing step, of removing the Al from the intermediate so that a proportion of the Al to a total of the Si and the Al is 0.1 atm % or more and 1 atm % or less in the active material,
wherein the active material includes a silicon clathrate II type crystal phase as a main phase.
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