Negative electrode material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery
Disclosed is a negative electrode material for a non-aqueous electrolyte secondary battery, including: a lithium silicate phase; silicon particles dispersed in the lithium silicate phase; and at least one element Me dispersed in the lithium silicate phase, and selected from the group consisting of a rare-earth element and an alkaline-earth metal. The composition of the lithium silicate phase is represented, for example, by the formula: Li 2z SiO 2+z , and satisfies 0<z<2, and the element Me is dispersed in the lithium silicate phase, for example, as an Me oxide.
1. A negative electrode material for a non-aqueous electrolyte secondary battery, comprising:
a lithium silicate phase;
silicon particles dispersed in the lithium silicate phase; and
at least one element Me dispersed in the lithium silicate phase, and selected from the group consisting of a rare-earth element and an alkaline-earth metal.
2. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the composition of the lithium silicate phase is represented by the formula: Li 2z SiO 2+z , and satisfies 0<z<2.
3. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the element Me is dispersed in the lithium silicate phase as an Me oxide, and
an amount of the Me oxide is 0.001 mass % or more and 1.0 mass % or less, relative to a total amount of the lithium silicate phase and the silicon particles.
4. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 3 ,
wherein the Me oxide includes at least one selected from the group consisting of an yttrium oxide, a cerium oxide, a calcium oxide, and a magnesium oxide.
5. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the lithium silicate phase includes a zirconium oxide, and
the element Me is dispersed in the zirconium oxide.
6. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 5 ,
wherein the zirconium oxide has an average particle size of 200 nm or less.
7. The negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1 ,
wherein the silicon particles have an average particle size of 200 nm or less before initial charging.
8. A non-aqueous electrolyte secondary battery comprising:
a negative electrode including the negative electrode material for a non-aqueous electrolyte secondary battery according to claim 1 ; a positive electrode capable of electrochemically absorbing and desorbing lithium; and a non-aqueous electrolyte.