Silicon-oxygen composite material, anode material, anode and lithium ion battery and preparation method thereof
Providing a silicon-oxygen composite material, an anode material and a preparation method thereof. The silicon-oxygen composite material has a size D10 of in a range of 3.0 μm to 8.2 μm. In the present disclosure, by controlling the particle size D10 of the silicon-oxygen composite material to between 3.0 μm and 8.2 μm, on the one hand, the uniformity of pre-lithiation can be improved, the nano-silicon cannot be exposed on a surface of the particles, and desired improvement of initial Coulombic efficiency and good cycle stability can be obtained; on the other hand, the silicon-oxygen composite material has a suitable electron and ion conduction channels, and internal resistance of the particles is small, which improves the rate performance and cycle performance of the material.
1 . A silicon-oxygen composite material, comprising an inner core and a carbon layer formed on a surface of the inner core,
wherein the inner core comprises a lithium-containing compound and a non-metallic silicon-containing material, the non-metallic silicon-containing material comprises nano-silicon and silicon oxide, the non-metallic silicon-containing material is dispersed in the lithium-containing compound;
wherein the silicon-oxygen composite material has a D10 of 3.0 μm to 8.2 μm.
2 . The silicon-oxygen composite material of claim 1 , wherein the lithium-containing compound comprises at least one of lithium silicate, lithium carbonate, lithium aluminate, and lithium nitrate; and/or
the silicon oxide has a chemical formula of SiO x , wherein 0<x≤1.8; and/or
the nano-silicon is dispersed in the silicon oxide, and/or, the nano-silicon is dispersed in the lithium-containing compound; and/or
a mass ratio of the nano-silicon dispersed in the silicon oxide to the nano-silicon dispersed in the lithium-containing compound is (15-46):(54-75); and/or
the nano-silicon has a D50 of 0 to 15 nm, and excluding 0.
3 . The silicon-oxygen composite material of claim 1 , wherein the lithium-containing compound comprises at least one of lithium chloride, lithium nitride, lithium carbide, lithium sulfide, and lithium sulfate.
4 . The silicon-oxygen composite material of claim 1 , wherein a molar ratio of the nano-silicon to the lithium-containing compound is (0.5-10):1 and/or
a molar ratio of the silicon oxide to the lithium-containing compound is (0.2-2):1; and/or
the carbon layer comprises at least one of amorphous carbon, graphene sheet, graphitizable soft carbon, carbon fiber, carbon nanotube, and conductive carbon black; and/or
a mass content of the carbon layer is 1% to 15% based on 100% by mass of the silicon-oxygen composite material; and/or
the carbon layer has a thickness of 200 nm to 1000 nm.
5 . An anode material, comprising the silicon-oxygen composite material of claim 1 .
6 . The anode material of claim 5 , wherein the anode material is a composite of graphite and the silicon-oxygen composite material.
7 . The anode material of claim 5 , wherein the anode material is a composite of lithium titanate and the silicon-oxygen composite material.
8 . A preparation method of a silicon-oxygen composite material, comprising the followings:
adjusting a particle size of a silicon source such that a particle size D10 of the silicon source is 2.5 μm to 7.5 μm;
carbon-coating the silicon source having adjusted particle size to obtain a carbon-containing silicon-oxygen precursor; and
mixing the carbon-containing silicon-oxygen precursor and a lithium source, roasting, to obtain the silicon-oxygen composite material;
wherein the silicon-oxygen composite material has a particle size D10 of 3.0 μm to 8.2 μm.
9 . The preparation method of claim 8 , wherein a method for preparing the silicon source comprises: heating a raw material capable of producing silicon oxide gas under an inert atmosphere to produce silicon oxide gas, and obtaining the silicon source after cooling down.
10 . The preparation method of claim 9 , comprising at least one of the following features (1) to (5):
(1) the silicon source is silicon monoxide;
(2) the inert atmosphere comprises at least one of helium atmosphere, neon atmosphere, argon atmosphere, krypton atmosphere, xenon atmosphere, and nitrogen atmosphere;
(3) a temperature of the heating is 900° C. to 1500° C.;
(4) the raw material capable of producing silicon oxide gas is a mixture of Si and SiO 2 ;
(5) a method for adjusting a particle size comprises at least one of crushing, ball milling, and classification.
11 . The preparation method of claim 8 , wherein a method for the carbon-coating comprises at least one of a gas-phase carbon-coating process and a solid-phase carbon-coating process; and/or
the gas-phase carbon-coating process comprises: mixing the silicon source having adjusted particle size and an organic carbon source under a protective atmosphere, and heating to obtain the carbon-containing silicon-oxygen precursor; and/or
the solid-phase carbon-coating process comprises: fusing the silicon source having an adjusted particle size with a coated carbon source, and obtaining the carbon-containing silicon-oxygen precursor after carbonization.
12 . The preparation method of claim 11 , wherein a gas in the protective atmosphere comprises at least one of hydrogen, nitrogen, helium, neon, argon, krypton, and xenon; and/or
the organic carbon source comprises at least one of methane, ethylene, acetylene, acetone, and benzene; and/or
the heating temperature is 600° C. to 1000° C.; and/or
a time of the fusing is 0.2 h to 1 h; and/or
the coated carbon source comprises at least one of coal coke, petroleum coke, sugar, organic acid, and pitch; and/or
a temperature of the carbonization is 600° C. to 1000° C.; and/or
a time of the carbonization is 3 h to 10 h; and/or
the carbon-containing silicon-oxygen precursor has a particle size D10 of 3.0 μm to 8.2 μm.
13 . The preparation method of claim 11 , wherein the carbon source comprises an organic carbon source that is decomposed to form a carbon layer at 600° C. to 1000° C.; and/or
the organic carbon source comprises at least one of alkane, alkene, alkyne, ketone, and aromatic hydrocarbon; and/or
the coated carbon source comprises at least one of needle coke, resin, polyol, and enol.
14 . The preparation method of claim 8 , wherein the lithium source comprises an oxygen-free lithium compound; and/or
the lithium source comprises at least one of lithium hydride, lithium amide, alkyl lithium, lithium aluminum hydride, lithium element, and lithium borohydride; and/or
the lithium source has a particle size D10 of 0.5 μm to 10 μm; and/or
a molar ratio of the carbon-containing silicon-oxygen precursor to the lithium source is (1.4-3):1; and/or
a manner of mixing the carbon-containing silicon-oxygen precursor and the lithium source comprises at least one of VC mixing, blending, fusion, kneading, dispersion, and stirring; and/or
the roasting is performed in a non-oxygen atmosphere; and/or
the non-oxygen atmosphere comprises at least one of a vacuum atmosphere, a hydrogen atmosphere, a nitrogen atmosphere, a helium atmosphere, a neon atmosphere, an argon atmosphere, a krypton atmosphere, and a xenon atmosphere; and/or
a temperature of the roasting is 300° C. to 1000° C.
15 . The preparation method of claim 8 , comprising the following:
heating a mixture of Si and SiO 2 to 900° C. to 1500° C. under an inert atmosphere to produce silicon oxide gas, cooling down, and adjusting particle size, to obtain a silicon source with a particle size D10 of 2.5 μm to 7.5 μm;
carbon-coating the silicon source having adjusted particle size to obtain a carbon-containing silicon-oxygen precursor with a particle size D10 of 3.0 μm to 8.2 μm; and
mixing the carbon-containing silicon-oxygen precursor with a lithium source, and calcinating at a temperature of 450° C. to 800° C. in a non-oxygen atmosphere, to obtain a silicon-oxygen composite material with a particle size D10 of 3.0 μm to 8.2 μm.