Cathode active material for lithium-sulfur battery, comprising metal sulfide nanoparticles, and method for producing same

Patent metadata

Field	Value
Publication number	US-2019267625-A1
Application number	US-201716308316-A
Country	US
Kind code	A1
Filing date	Nov 28, 2017
Priority date	Nov 28, 2016
Publication date	Aug 29, 2019
Grant date	—

Abstract

A positive electrode active material for a lithium-sulfur battery, and more particularly, to a positive electrode active material for a lithium-sulfur battery including metal sulfide nanoparticles and a preparation method thereof. The metal sulfide nanoparticles with large specific surface area applied to the positive electrode active material for the lithium-sulfur battery according to the present invention acts as a redox mediator during charging and discharging of the lithium-sulfur battery, thereby reducing the shuttle response by not only inhibiting the formation itself of polysulfides with elution properties, but also, even if polysulfides are eluted, adsorbing them and thus preventing them from diffusing into the electrolyte solution, and thus the capacity and life characteristics of the lithium-sulfur battery can be improved.

First claim

1 . A positive electrode active material for a lithium-sulfur battery, which comprises:
a sulfur/carbon composite; and metal sulfide nanoparticles.

2 . The positive electrode active material for the lithium-sulfur battery according to claim 1 , wherein the metal sulfide nanoparticles are compounds represented by M x S y (wherein
x and y are integers that satisfy 0<x≤5 and 0<y≤5 respectively, and M is at least one metal selected from the group consisting of cobalt (Co), molybdenum (Mo), titanium (Ti), nickel (Ni), copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), manganese (Mn), antimony (Sb), arsenic (As), silver (Ag) and mercury (Hg).

3 . The positive electrode active material for the lithium-sulfur battery according to claim 1 , wherein an average particle diameter of the metal sulfide nanoparticles is 0.1 to 200 nm.

4 . The positive electrode active material for the lithium-sulfur battery according to claim 1 , wherein the metal sulfide nanoparticles are included in an amount of 1 to 20% by weight based on the total weight of the positive electrode active material.

5 . A preparation method of the positive electrode active material for the lithium-sulfur battery according to claim 1 , which is prepared by
mixing the metal sulfide nanoparticles with the sulfur/carbon composite, wherein the preparation method of the metal sulfide nanoparticles comprises the following steps of; i) preparing a sulfur precursor solution and a metal precursor solution; ii) mixing the sulfur precursor solution and the metal precursor solution; iii) reacting the mixed solution of ii) at 50 to 100° C. for 5 to 24 hours; iv) washing and purifying the solution resulting from iii); and v) performing the drying.

6 . The preparation method of the positive electrode active material for the lithium-sulfur battery according to claim 5 , wherein the sulfur precursor solution is a solution in which at least one compound selected from the group consisting of thioacetamide (TAA), thiourea, and sodium sulfide (Na 2 S) is dissolved in a solvent.

7 . The preparation method of the positive electrode active material for the lithium-sulfur battery according to claim 5 , wherein the sulfur precursor solution contains a surfactant.

8 . The preparation method of the positive electrode active material for the lithium-sulfur battery according to claim 5 , wherein the metal precursor solution is a solution including at least one compound selected from the group consisting of acetate, hydroxide, nitrate, nitride, sulfate, sulfide, alkoxide and halide, and which metal precursor solution contains at least one selected from the group consisting of cobalt (Co), molybdenum (Mo), titanium (Ti), nickel (Ni), copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), manganese (Mn), antimony (Sb), arsenic (As), silver (Ag) and mercury (Hg).

9 . (canceled)

10 . A lithium-sulfur battery, comprising:
a positive electrode; a negative electrode; and electrolyte, wherein the positive electrode comprises the positive electrode active material according to claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Lee Dongwook
• Jung Jongwook
• Sohn Kwonnam
• Yang Doo Kyung
• Hwang Gyo Hyun

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/5815 Primary

  Sulfides · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M10/052 Primary

  Li-accumulators · CPC title

• C01B32/70

  Compounds containing carbon and sulfur, e.g. thiophosgene · CPC title