Cathode active material for lithium-ion secondary battery and preparation method thereof, cathode pole piece for lithium-ion secondary battery, and lithium-ion secondary battery

Patent metadata

Field	Value
Publication number	US-10454094-B2
Application number	US-201414580030-A
Country	US
Kind code	B2
Filing date	Dec 22, 2014
Priority date	Jul 29, 2013
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

Embodiments of the present invention provide a cathode active material for a lithium-ion secondary battery, where the cathode active material for a lithium-ion secondary battery includes a silicon-based active substance and a nitrogen-doped carbon material. The silicon-based active substance is encased in the interior of the nitrogen-doped carbon material, and the silicon-based active substance is one or more of a nanoparticle and a nanowire; a micropore is arranged on at least one of the exterior and the interior of the nitrogen-doped carbon material; and a material of the nitrogen-doped carbon material is a nitrogen-doped carbon network. The cathode active material for a lithium-ion secondary battery solves a problem in the prior art that a silicon material, when used as a cathode active material, easily falls from a current collector due to a great volume change and has a low conductivity.

First claim

What is claimed is:

1. A cathode active material for a lithium-ion secondary battery, the cathode active material comprising:
a silicon-based active substance comprising one or more of nanoparticles or nanowires;
a nitrogen-doped carbon material comprising a nitrogen-doped carbon network, wherein the nitrogen-doped carbon material comprises a plurality of interlinked branches formed by the nitrogen-doped carbon network, the silicon-based active substance is encased in an interior of the nitrogen-doped carbon material, wherein a particle diameter of the silicon-based active substance nanoparticle is 1 nm-1 μm, and the nanowire is 1-200 nm in diameter and 1-10 μm long;
micropores arranged on at least one of an exterior or an interior of the plurality of interlinked branches of the nitrogen-doped carbon material, wherein an aperture of the micropore ranges between 0.5-500 nm;
wherein a nitrogen atom and a carbon atom in the nitrogen-doped carbon network are bonded in at least one form of pyridinic nitrogen, graphite nitrogen or pyrrolic nitrogen; and
wherein a mass ratio of the silicon-based active substance to the cathode active material is 5%-50%.

2. The cathode active material for a lithium-ion secondary battery according to claim 1 , wherein a ratio of the particle diameter of the silicon-based active substance nanoparticle to the aperture of the micropore is 1-10:1.

3. The cathode active material for a lithium-ion secondary battery according to claim 1 , wherein the branches are 1 nm-10 μm in diameter.

4. The cathode active material for a lithium-ion secondary battery according to claim 1 , wherein the nitrogen-doped carbon network comprises pyrrolic nitrogen.

5. The cathode active material for a lithium-ion secondary battery according to claim 1 , wherein the material of the silicon-based active substance is selected from one or more of simple substance silicon, silicon oxide or silicon alloy.

6. A cathode pole piece for a lithium-ion secondary battery, the cathode pole piece comprising:
a current collector;
a cathode active material coated on the current collector and comprising a silicon-based active substance and a nitrogen-doped carbon material, wherein the silicon-based active substance is encased in an interior of the nitrogen-doped carbon material, and the silicon-based active substance comprising one or more of nanoparticles or nanowires, wherein a particle diameter of the silicon-based active substance nanoparticle is 1 nm-1 μm, and the nanowire is 1-200 nm in diameter and 1-10 μm long;
micropores arranged on at least one of an exterior or the interior of the nitrogen-doped carbon material, and wherein an aperture of the micropore ranges between 0.5-500 nm; and
a material of the nitrogen-doped carbon material is a nitrogen-doped carbon network, wherein a nitrogen atom and a carbon atom in the nitrogen-doped carbon network are bonded in at least one form of pyridinic nitrogen, graphite nitrogen or pyrrolic nitrogen;
wherein the nitrogen-doped carbon material is in a shape of a three-dimensional network and the nitrogen-doped carbon material comprises a plurality of interlinked branches, the micropores are arranged on the plurality of interlinked branches of the nitrogen-doped carbon material; and
wherein a mass ratio of the silicon-based active substance to the cathode active material is 5%-50%.

7. A lithium-ion secondary battery comprising:
an anode pole piece;
a membrane;
a non-aqueous electrolyte and a casing; and
a cathode pole piece, wherein the cathode pole piece comprises:
a current collector;
a cathode active material coated on the current collector and comprising a silicon-based active substance and a nitrogen-doped carbon material, wherein the silicon-based active substance is encased in an interior of the nitrogen-doped carbon material, and the silicon-based active substance comprising one or more of nanoparticles or nanowires, and wherein a particle diameter of the silicon-based active substance nanoparticle is 1 nm-1 μm, and the nanowire is 1-200 nm in diameter and 1-10 μm long;
a micropore arranged on at least one of an exterior or the interior of the nitrogen-doped carbon material, and wherein an aperture of the micropore ranges between 0.5-500 nm; and
a material of the nitrogen-doped carbon material is a nitrogen-doped carbon network, wherein a nitrogen atom and a carbon atom in the nitrogen-doped carbon network are bonded in at least one form of pyridinic nitrogen, graphite nitrogen or pyrrolic nitrogen;
wherein the nitrogen-doped carbon material is in a shape of a three-dimensional network and the nitrogen-doped carbon material comprises a plurality of interlinked branches, the micropores are arranged on the plurality of interlinked branches of the nitrogen-doped carbon material; and
wherein a mass ratio of the silicon-based active substance to the cathode active material is 5%-50%.

Assignees

• Huawei Tech Co Ltd

Inventors

• Xia Shengan
• Yang Jun
• Wang Pinghua

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/583

  Carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title