Negative electrode active material, negative electrode including the negative electrode active material, secondary battery including the negative electrode, and method of preparing the negative electrode active material

Patent metadata

Field	Value
Publication number	US-2021257617-A1
Application number	US-201917252431-A
Country	US
Kind code	A1
Filing date	Oct 18, 2019
Priority date	Oct 19, 2018
Publication date	Aug 19, 2021
Grant date	—

Abstract

According to an exemplary embodiment of the present disclosure, a negative electrode active material includes metal-silicon-carbon based particles including a MaSibC matrix, wherein M in the MaSibC matrix is one or more selected from the group consisting of Li, Mg, Na, Ca, and Al, 0.3≤a≤1, and 1≤b≤2. Since at the time of charging and discharging a battery, formation of an irreversible phase may be minimized by the MaSibC matrix, initial efficiency of the battery may be improved, and electrical conductivity, physical strength, and chemical stability may be improved, such that capacity and lifecycle characteristics of the battery may be improved.

First claim

1 . A negative electrode active material comprising metal-silicon-carbon based particles including a M a Si b C matrix, wherein M in the M a Si b C matrix is one or more selected from the group consisting of Li, Mg, Na, Ca, and Al, 0.3≤a≤1, and 1≤b≤2.

2 . The negative electrode active material according to claim 1 , wherein an average particle size (D 50 ) of the metal-silicon-carbon based particles is 1 μm to 10 μm.

3 . The negative electrode active material according to claim 1 , wherein the M a Si b C matrix includes Si, SiC, and M x Si y C,
M in M x Si y C being one or more selected from the group consisting of Li, Mg, Na, Ca, and Al, 1<x≤3, and 0.5<y≤2.

4 . The negative electrode active material according to claim 1 , wherein the M a Si b C matrix includes 10 wt % to 35 wt % of M, 45 wt % to 75 wt % of Si, and 15 wt % to 25 wt % of C based on a total weight of M a Si b C matrix.

5 . The negative electrode active material according to claim 1 , wherein in the M a Si b C matrix, a weight ratio of Si to M is 1.5 to 7.

6 . A method of preparing the negative electrode active material according to claim 1 , the method comprising forming a matrix fluid through thermal treatment by introducing a vaporized silicon source, a carbon source, a metal source, and a carrier gas into a reaction furnace, wherein in the forming of the matrix fluid, a ratio of a flow rate of the vaporized silicon source, a flow rate of the carbon source, and a flow rate of the metal source is 1:0.2:0.2 to 1:0.8:0.8.

7 . The method according to claim 6 , wherein the thermal treatment is performed at 1,000° C. to 2,500° C.

8 . The method according to claim 6 , wherein the carrier gas is one or more selected from the group consisting of Ar, He, and Ne.

9 . A negative electrode comprising the negative electrode active material of claim 1 .

10 . The negative electrode according to claim 9 , further comprising a graphite based active material.

11 . A secondary battery comprising:
the negative electrode of claim 9 ; a positive electrode; a separator interposed between the positive electrode and the negative electrode; and and an electrolyte.

Assignees

• Lg Chemical Ltd

Inventors

• Oh Il Geun
• Lee Yong Ju
• Lee Su Min

Classifications

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• C01B32/963

  Preparation from compounds containing silicon · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/40

  Alloys based on alkali metals · CPC title