SECONDARY BATTERY NEGATIVE ELECTRODE ACTIVE MATERIAL, SECONDARY BATTERY, AND METHOD FOR MANUFACTURING THEM

To provide: a secondary battery negative electrode active material small in initial irreversible capacity, long in service life and high in capacity, in a negative electrode active material having a large volumetric change of an active material due to charge/discharge; a secondary battery negative electrode and a secondary battery using the same; and a method of manufacturing them.SOLUTION: A method of manufacturing a secondary battery negative electrode active material includes: a step (1) of inserting alkaline metal into a negative electrode active material (a1) to adjust a negative electrode active material (a2) in a swollen state; and a step (2) of covering part or all of a surface of the negative electrode active material (a2) with a conductive material.SELECTED DRAWING: Figure 1 【課題】充放電に伴う活物質の体積変化が大きい負極活物質について、初回不可逆容量が小さく、長寿命かつ大容量の二次電池用負極活物質、それを用いた二次電池用負極および二次電池、ならびに、それらの製造方法を提供することを目的とする。【解決手段】負極活物質（ａ１）にアルカリ金属を挿入させて膨潤状態の負極活物質（ａ２）を調整する工程（１）、および、前記負極活物質（ａ２）の表面の一部または全部を導電性材料で被覆する工程（２）、を含むことを特徴とする、二次電池負極活物質の製造方法。【選択図】図１