Lithium ion battery cathode material and preparation method thereof, and lithium ion battery

Abstract

The invention discloses a lithium ion battery cathode material and a preparation method thereof, and a lithium ion battery. The preparation method of the material comprises the following steps: 1)mixing metal and SiOx to obtain a mixture, wherein, metal is one or more from lithium, sodium, potassium, calcium, magnesium and titanium, and x is greater than 0 and less than 2.0; and 2)under inert atmosphere or vacuum condition, roasting the mixture for 0.5-24 hours at 300-1000 DEG C to obtain the cathode material. By reacting the metal and SiOx, active oxygen content in the cathode material is reduced, and the obtained cathode material also comprises the above metal oxide. According to the invention, active oxygen content in the cathode material is reduced, primary efficiency for charge and discharge can be greatly increased, the above metal oxide in the cathode material can alleviate volume expansion of silicon in the cathode material at certain degree, and thereby the volume effect of the whole cathode material is reduced.

Description

technical field

[0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode material, a preparation method thereof, and a lithium ion battery. Background technique

[0002] At present, the lithium-ion batteries used in production mainly use graphite-based negative electrode materials, but the theoretical lithium intercalation capacity of graphite is 372mAh / g, but it has actually reached 370mAh / g. Therefore, there is almost no room for improvement in the capacity of graphite-based negative electrode materials.

[0003] In the past ten years, a variety of new high-capacity and high-rate negative electrode materials have been developed, among which silicon-based materials have become a research hotspot due to their high mass specific capacity (the theoretical specific capacity of silicon is 4200mAh / g). The material is accompanied by serious volume expansion and contraction during the lithium...

Examples

Embodiment 1

[0024] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0025] (1) Metal lithium and SiO 0.5 mixed, wherein the particle size of lithium metal is 5 μm, SiO 0.5 The particle size is 15 μm, resulting in a mixture that includes SiO 0.5 and lithium metal, where SiO 0.5 The mass ratio to lithium metal is 2:1.

[0026] (2) Put the mixture obtained in step (1) into a high-temperature furnace with an inert atmosphere for burning, first raise the temperature to 120°C at a rate of 5°C / min, keep it warm for 2 hours, and then heat it up at a rate of 5°C / min The temperature was raised to 800° C., and the temperature was maintained for 4 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 0.5 When the mass ratio to metal lithium is 2:1, the metal lithium can fully reduce the active oxygen in the final lithium ion negative electrode material and improve the first c...

Embodiment 2

[0035] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0036] (1) Metal sodium and SiO 1.5 mixed, wherein the particle size of metallic sodium is 0.1 μm, SiO 1.5 The particle size is 1 μm, resulting in a mixture that includes SiO 1.5 and metallic sodium, where SiO 1.5 The mass ratio to metal sodium is 1:1.

[0037] (2) Put the mixture obtained in step (1) into a high-temperature furnace with an argon atmosphere and burn it. First, heat up to 50°C at a heating rate of 5°C / min, keep it warm for 2 hours, and then heat it up at a heating rate of 5°C / min. The heating rate is raised to 400° C., and the temperature is kept for 24 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 1.5 When the mass ratio to metal sodium is 1:1, metal sodium can fully reduce the active oxygen in the final lithium ion negative electrode material and improve the first charge ...

Embodiment 3

[0041] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0042] (1) Metal calcium, metal titanium and SiO 1.9 Mixed by ball milling, wherein the particle size of metal calcium and metal titanium are both 2 μm, SiO 1.9 The particle size is 10 μm, resulting in a mixture that includes SiO 1.9 , metal calcium and metal titanium, among them, SiO 1.9 The mass ratio to the mass sum of metallic calcium and metallic titanium is 0.4:1.

[0043] (2) Put the mixture obtained in step (1) into a high-temperature furnace with a helium atmosphere for burning, first raise the temperature to 80°C at a heating rate of 5°C / min, keep it warm for 2 hours, and then heat it at a heating rate of 5°C / min The heating rate is raised to 700° C., and the temperature is kept for 12 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 1.9 When the mass ratio of the mass sum of metal ...

technical field

[0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode material, a preparation method thereof, and a lithium ion battery. Background technique

[0002] At present, the lithium-ion batteries used in production mainly use graphite-based negative electrode materials, but the theoretical lithium intercalation capacity of graphite is 372mAh / g, but it has actually reached 370mAh / g. Therefore, there is almost no room for improvement in the capacity of graphite-based negative electrode materials.

[0003] In the past ten years, a variety of new high-capacity and high-rate negative electrode materials have been developed, among which silicon-based materials have become a research hotspot due to their high mass specific capacity (the theoretical specific capacity of silicon is 4200mAh / g). The material is accompanied by serious volume expansion and contraction during the lithium...

Examples

Embodiment 1

[0024] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0025] (1) Metal lithium and SiO 0.5 mixed, wherein the particle size of lithium metal is 5 μm, SiO 0.5 The particle size is 15 μm, resulting in a mixture that includes SiO 0.5 and lithium metal, where SiO 0.5 The mass ratio to lithium metal is 2:1.

[0026] (2) Put the mixture obtained in step (1) into a high-temperature furnace with an inert atmosphere for burning, first raise the temperature to 120°C at a rate of 5°C / min, keep it warm for 2 hours, and then heat it up at a rate of 5°C / min The temperature was raised to 800° C., and the temperature was maintained for 4 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 0.5 When the mass ratio to metal lithium is 2:1, the metal lithium can fully reduce the active oxygen in the final lithium ion negative electrode material and improve the first c...

Embodiment 2

[0035] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0036] (1) Metal sodium and SiO 1.5 mixed, wherein the particle size of metallic sodium is 0.1 μm, SiO 1.5 The particle size is 1 μm, resulting in a mixture that includes SiO 1.5 and metallic sodium, where SiO 1.5 The mass ratio to metal sodium is 1:1.

[0037] (2) Put the mixture obtained in step (1) into a high-temperature furnace with an argon atmosphere and burn it. First, heat up to 50°C at a heating rate of 5°C / min, keep it warm for 2 hours, and then heat it up at a heating rate of 5°C / min. The heating rate is raised to 400° C., and the temperature is kept for 24 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 1.5 When the mass ratio to metal sodium is 1:1, metal sodium can fully reduce the active oxygen in the final lithium ion negative electrode material and improve the first charge ...

Embodiment 3

[0041] This embodiment provides a preparation method of lithium ion battery negative electrode material, comprising the following steps:

[0042] (1) Metal calcium, metal titanium and SiO 1.9 Mixed by ball milling, wherein the particle size of metal calcium and metal titanium are both 2 μm, SiO 1.9 The particle size is 10 μm, resulting in a mixture that includes SiO 1.9 , metal calcium and metal titanium, among them, SiO 1.9 The mass ratio to the mass sum of metallic calcium and metallic titanium is 0.4:1.

[0043] (2) Put the mixture obtained in step (1) into a high-temperature furnace with a helium atmosphere for burning, first raise the temperature to 80°C at a heating rate of 5°C / min, keep it warm for 2 hours, and then heat it at a heating rate of 5°C / min The heating rate is raised to 700° C., and the temperature is kept for 12 hours to obtain the lithium ion battery negative electrode material. When SiO in the mixture 1.9 When the mass ratio of the mass sum of metal ...