Battery

1. A battery comprising a cathode layer, an electrolyte layer, and an anode layer, in this order, and

the anode layer includes a silicon clathrate compound, as an anode active material,

the silicon clathrate compound has a composition represented by M x Si 46 , wherein M is a metal element, x satisfies 0<x<8, and includes a crystal phase of a Type I silicon clathrate,

an average primary particle size of the silicon clathrate compound is 50 nm or more and 3000 nm or less,

the silicon clathrate compound includes the crystal phase of the Type I silicon clathrate as a main phase, and

the silicon clathrate compound includes at least a Na element, as the M.

2. The battery according to claim 1 , wherein an average secondary particle size of the silicon clathrate compound is 1 μm or more and 40 μm or less.

3. The battery according to claim 1 , wherein the average primary particle size of the silicon clathrate compound is 100 nm or more and 1000 nm or less, and

an average secondary particle size of the silicon clathrate compound is 2 μm or more and 20 μm or less.

4. The battery according to claim 1 , wherein the electrolyte layer includes an inorganic solid electrolyte.

5. The battery according to claim 1 , wherein the electrolyte layer includes a liquid electrolyte.

6. The battery according to claim 1 , wherein the battery is a lithium ion battery.

7. The battery according to claim 1 , wherein the battery is a sodium ion battery.

8. The battery according to claim 1 , wherein

the x satisfies 0<x<6.