Lithium metal secondary battery having improved life characteristics

Patent metadata

Field	Value
Publication number	US-11437626-B2
Application number	US-201916980701-A
Country	US
Kind code	B2
Filing date	Apr 3, 2019
Priority date	Apr 6, 2018
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A lithium metal secondary battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a protective layer interposed between the negative electrode and the separator. The protective layer includes an additive, wherein the additive comprises a mixture of hexagonal boron nitride (BN) flakes with an ionomer having a sulfur (S)-containing anionic group and fluorine (F).

First claim

What is claimed is:

1. A lithium metal secondary battery comprising:
a positive electrode;
a negative electrode;
a separator interposed between the positive electrode and the negative electrode; and
a protective layer interposed between the negative electrode and the separator, wherein the protective layer comprises an additive, and wherein the additive comprises a mixture of hexagonal boron nitride (BN) flakes and an ionomer represented by the following formula:

wherein m:n ranges from 1:1 to 10:1.

2. The lithium metal secondary battery according to claim 1 , wherein the protective layer is a porous polymer layer, an inorganic layer, or a laminate comprising a porous polymer layer and an inorganic layer.

3. The lithium metal secondary battery according to claim 2 , wherein the protective layer is the porous polymer layer, which comprises at least one selected from the group consisting of polyvinyl chloride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyethylhexyl acrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylidene fluoride, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polypropylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan and carboxyl methyl cellulose.

4. The lithium metal secondary battery according to claim 2 , wherein the protective layer is the inorganic layer, which comprises at least one selected from the group consisting of SiO 2 , BaTiO 3 , Pb(Zr x Ti l-x )O 3 (PZT, 0<x<1), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT, 0<x<1, 0<y<1), (1-x)Pb(Mg 1/3 Nb 2/3 )O 3-x PbTiO 3 (PMNPT, 0<x<1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , AlOOH, lithium lanthanum ziroconium oxide (LLZO), Si 3 N 4 , TiC, TiO 2 and SiC.

5. The lithium metal secondary battery according to claim 1 , wherein the protective layer has a thickness range of from 0.1 μm to 10 μm.

6. The lithium metal secondary battery according to claim 1 , wherein the additive is used in an amount of 50 wt % to 98 wt % based on a total weight of the protective layer.

7. The lithium metal secondary battery according to claim 1 , wherein the additive comprises the hexagonal boron nitride flakes and the ionomer mixed at a weight ratio of 1:9 to 9:1.

8. A lithium metal secondary battery comprising:
a positive electrode;
a negative electrode;
a separator interposed between the positive electrode and the negative electrode, wherein the positive electrode and/or negative electrode comprises a solid electrolyte, and
wherein the solid electrolyte comprises an additive, wherein the additive comprises a mixture of hexagonal boron nitride (BN) flakes with an ionomer represented by the following formula:

wherein m:n ranges from 1:1 to 10:1.

9. The lithium metal secondary battery according to claim 8 , wherein the additive is added in the form of an additive mixture combined with the solid electrolyte.

10. The lithium metal secondary battery according to claim 9 , wherein the solid electrolyte comprises at least one selected from the group consisting of a polymer solid electrolyte, polymer gel electrolyte, sulfide-based solid electrolyte and an oxide-based solid electrolyte.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Yoon Jong-Keon
• Park Sol-Ji
• Yun Hyun-Woong
• Ahn Kyoung-Ho
• Hah Hoe-Jin

Classifications

• H01M50/417

  Polyolefins · CPC title

• C08K3/38

  Boron-containing compounds · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M10/4235 Primary

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M2300/0071

  Oxides · CPC title