Active material, battery, and methods for producing these
A main object of the present disclosure is to provide an active material wherein a volume variation due to charge/discharge is small. The present disclosure achieves the object by providing an active material comprising at least Si and Al, including a silicon clathrate type crystal phase, and 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.
1. An active material comprising at least Si and Al,
including a silicon clathrate type crystal phase, and
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 and the active material is represented by Na x (Si, Al) 136 , where 0≤x≤20.
2. The active material according to claim 1 , wherein the active material includes a void inside a primary particle.
3. The active material according to claim 2 , wherein a void ratio of the void is 2% or more and 15% or less.
4. The active material according to claim 1 , wherein the active material includes a silicon clathrate II type crystal phase as the silicon clathrate type crystal phase.
5. A battery comprising a cathode layer, an anode layer, and an electrolyte layer formed between the cathode layer and the anode layer, and
the anode layer includes the active material according to claim 1 .