Anode active material for batteries, and method for preparing same
An anode active material for batteries including anode active substance particles that include a silicon oxide compound. The anode active substance particles includes lithium and a non-lithium doping metal, where the non-lithium doping metal includes a metal M 1 including one or more of titanium, magnesium, zirconium, zinc, aluminum, yttrium and calcium, and the content of the non-lithium doping metal in the anode active material is 0.01-20 wt %, for example 0.05-15 wt %, in another example 0.1-10 wt %, and in still another example 0.1-5 wt %. The anode active material has high water tolerance, and a secondary battery prepared from the anode active material has the advantages of high capacity, high coulombic efficiency and long cycle life.
1. An anode active material for batteries, comprising anode active substance particles, the anode active substance particles comprising a silicon oxide compound,
wherein the anode active substance particles further comprise lithium and a non-lithium doping metal, and
wherein the non-lithium doping metal comprises a metal M 1 including one or more of titanium, magnesium, zirconium, zinc, aluminum, yttrium and calcium, and a content of the metal M 1 in the anode active material is 0.01-20 wt %;
wherein the metal M 1 exists in the anode active material is in a form of an oxygen-containing compound, and the oxygen-containing compound is dispersedly distributed in the silicon oxide compound; and
wherein the anode active substance particles further comprise nano-silicon grains that are regularly dispersed in the anode active substance particles, and a median size of the nano-silicon grains is 1-15 nm.
2. The anode active material for batteries according to claim 1 , wherein the non-lithium doping metal further comprises a metal M 2 including one or more of copper, nickel, ferrum, manganese, cobalt and chromium.
3. The anode active material for batteries according to claim 2 , wherein a content of the metal M 2 in the anode active material is 0.01-20 wt %.
4. The anode active material for batteries according to claim 2 , wherein total contents of the metal M 1 and the metal M 2 in the anode active material are 0.01-25 wt %.
5. The anode active material for batteries according to claim 1 , wherein the oxygen-containing compound of the non-lithium doping metal comprises one or more of a metal oxide, a metal silicate, a lithium-containing composite metal silicate, and a composite oxide of lithium and a non-lithium doping metal.
6. The anode active material for batteries according to claim 1 , wherein the oxygen-containing compound is concentrated on a surface layer of the silicon oxide compound, and concentration of the oxygen-containing compound decreases gradually from the surface layer to an interior of the silicon oxide compound.
7. The anode active material for batteries according to claim 2 , wherein the metal M 2 exists in the anode active material in a form of an elemental metal phase or a silicon alloy phase.
8. The anode active material for batteries according to claim 1 , wherein a content of the lithium in the anode active substance particles is 0.1-20 wt %.
9. The anode active material for batteries according to claim 1 , wherein the anode active substance particles comprise at least one lithium-containing compound selected from Li 4 SiO 4 , Li 2 SiO 3 , Li 6 Si 2 O 7 , Li 8 SiO 6 and Li 2 Si 2 O 5 .
10. The anode active material for batteries according to claim 1 , wherein a median size of the anode active substance particles is 0.2-20 μm.
11. The anode active material for batteries according to claim 1 , wherein a content of silicon in the anode active substance particles is 30-80 wt %.
12. The anode active material for batteries according to claim 1 , wherein the anode active substance particles are coated with a carbon film covering a surface of the silicon oxide compound, and a thickness of the carbon film is 0.001-5 μm.
13. The anode active material for batteries according to claim 12 , wherein a weight ratio of the carbon film and the silicon oxide compound is 0.01:100-20:100 .
14. An electrode, comprising the anode active material according to claim 1 .
15. A method for preparing the anode active material according to claim 1 , comprising:
preparing silicon oxide compound particles; and
doping lithium and a non-lithium metal into the silicon oxide compound particles, wherein a stoichiometric ratio of silicon and oxygen in the silicon oxide compound particles is 1:0.4-1:2;
wherein the lithium is doped into the silicon oxide compound particles after the non-lithium metal is doped into the silicon oxide compound particles;
wherein a doping temperature of the non-lithium metal is 750-1100° C.
16. The method according to claim 15 , wherein a median size of the silicon oxide compound particles is 0.2-20 μm.
17. The method according to claim 15 , wherein the silicon oxide compound particles are coated with a carbon film.