Secondary battery and anode

Patent metadata

Field	Value
Publication number	US-9620810-B2
Application number	US-61730609-A
Country	US
Kind code	B2
Filing date	Nov 12, 2009
Priority date	Nov 14, 2008
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A secondary battery capable of obtaining superior cycle characteristics and superior swollenness characteristics is provided. The secondary battery includes a cathode and an anode capable of inserting and extracting an electrode reactant; and an electrolyte containing a solvent and an electrolyte salt. The anode has an anode active material layer on an anode current collector. The anode active material layer contains a plurality of crystalline anode active material particles having silicon (Si) as an element. The plurality of anode active material particles contain a spherical particle and a nonspherical particle.

First claim

What is claimed is:

1. A secondary battery comprising:
a cathode and an anode capable of inserting and extracting an electrode reactant; and
an electrolyte containing a solvent and an electrolyte salt,
wherein,
the anode has an anode active material layer on an anode current collector,
the anode active material layer comprises at least one layer which includes anode active material particles including a plurality of spherical crystalline particles having silicon (Si) as an element and a plurality of non-spherical particles each having a plate-like outline when viewed in cross-section,
at least some of the spherical crystalline particles are directly fixed to the anode current collector,
the number of whole spherical crystalline particles having a diameter of 0.1 μm to 40 μm, both inclusive, is 10 pieces to 200 pieces, both inclusive, as obtained as an average count per image for thirty 10.75 μm×16.00 μm SEM images at 8,000 times magnification, the images being of a surface of the anode active material layer,
at least part of each of the spherical crystalline particles has a planular shape, and
the anode active material layer includes a metal layer with metal material in at least some gaps between anode active material particles, the metal material not reacting with the electrode reactant.

2. The secondary battery according to claim 1 , wherein a half-width (2θ) of a diffraction peak in (111) crystal plane of the anode active material particles obtained by X-ray diffraction is 20° or less, or a crystallite size originated in the (111) crystal plane of the anode active material particles obtained by X-ray diffraction is 10 nm or more.

3. The secondary battery according to claim 1 , wherein the spherical crystalline particles have a median diameter from and including 0.5 μm to 35 μm.

4. The secondary battery according to claim 1 , wherein a circularity degree of the spherical particles is greater than or equal to 0.5 and less than 1.

5. The secondary battery according to claim 1 , wherein the anode active material particles are formed by spraying method.

6. The secondary battery according to claim 1 , wherein the anode active material particles are alloyed with at least part of an interface with the anode current collector.

7. The secondary battery according to claim 1 , wherein the anode active material particles are at least one of a simple substance, an alloy, and a compound of silicon.

8. The secondary battery according to claim 1 , wherein the anode active material particles have oxygen (O) as an element, and an oxygen content in the anode active material particles is from and including 1.5 atomic % to 40 atomic %.

9. The secondary battery according to claim 1 , wherein the anode active material particles have at least one metal element selected from the group consisting of iron (Fe), nickel (Ni), molybdenum (Mo), titanium (Ti), chromium (Cr), cobalt (Co), copper (Cu), manganese (Mn), zinc (Zn), germanium (Ge), aluminum (Al), zirconium (Zr), silver (Ag), tin (Sn), antimony (Sb), and tungsten (W).

10. The secondary battery according to claim 1 , wherein the anode active material layer comprises at least a first region containing an amount of oxygen and a second region containing an amount of oxygen less than the oxygen in the first region, the oxygen content being measured in a thickness direction.

11. The secondary battery according to claim 1 , wherein ten point height of roughness profile Rz of a surface of the anode current collector is 1.5 μm or more.

12. The secondary battery according to claim 1 , wherein the solvent contains at least one of:
(a) a chain ester carbonate having halogen as an element,
(b) a cyclic ester carbonate having halogen as an element,
(c) a cyclic ester carbonates having an unsaturated carbon bond,
(d) sultone, or
(e) an acid anhydride
wherein,
(1) the chain ester carbonate having halogen as an element is fluoromethyl methyl carbonate, bis(fluoromethyl) carbonate, difluoromethyl methyl carbonate, or any combination of them,
(2) the cyclic ester carbonate having halogen as an element is any one or a combination of chemical formulae 2-1 to 2-21, chemical formulae 2-1 to 2-21 being:

 and
(3) the cyclic ester carbonates having an unsaturated carbon bond is vinylene carbonate (1,3-dioxole-2-one), methylvinylene carbonate (4-methyl-1,3-dioxole-2-one), ethylvinylene carbonate (4-ethyl-1,3-dioxole-2-one), 4,5-dimethyl-1,3-dioxole-2-one, 4,5-diethyl-1,3-dioxole-2-one, 4-fluoro-1,3-dioxole-2-one, 4-trifluoromethyl-1,3-dioxole-2-one, vinyl ethylene carbonate (4-vinyl-1,3-dioxolane-2-one), 4-methyl-4-vinyl-1,3-dioxolane-2-one, 4-ethyl-4-vinyl-1,3-dioxolane-2-one, 4-n-propyl-4-vinyl-1,3-dioxolane-2-one, 5-methyl-4-vinyl-1,3-dioxolane-2-one, 4,4-divinyl-1,3-dioxolane-2-one, 4,5-divinyl-1,3-dioxolane-2-one, 4-methylene-1,3-dioxolane-2-one, 4,4-dimethyl-5-methylene-1,3-dioxolane-2-one, 4,4-diethyl-5-methylene-1,3-dioxolane-2-one, catechol carbonate having a benzene ring, or any combination of them.

13. The secondary battery according to claim 1 , wherein:
(1) the electrolyte salt contains lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), a compound shown in chemical formulae 6-1 to 6-6, a compound shown in chemical formulae 7-1 to 7-8, a compound shown in chemical formula 8-1, one or a combination of lithium bis(trifluoromethanesulfonyl)imide (LiN(CF 3 SO 2 ) 2 ), lithium bis(pentafluoroethanesulfonyl)imide (LiN(C 2 F 5 SO 2 ) 2 ), lithium (trifluoromethanesulfonyl)(pentafluoroethanesulfonyl)mide (LiN(CF 3 SO 2 )(C 2 F 5 SO 2 )), lithium(trifluoromethanesulfonyl)(heptafluoropropanesulfonyl)imide (LiN(CF 3 SO 2 )(C 3 F 7 SO 2 )), and lithium(trifluoromethanesulfonyl)(nonafluorobutanesulfonyl)imide (LiN(CF 3 SO 2 )(C 4 F 9 SO 2 )), a compound shown in chemical formula 10-1 to 10-4, lithium tris(trifluoromethanesulfonyl)methyde (LiC(CF 3 SO 2 ) 3 , or any combination of them;
(2) chemical formulae 6-1 to 6-6 are:

(3) chemical formulae 7-1 to 7-8 are:

(4) chemical formula 8-1 is

 and
(5) chemical formula 10-1 to 10-4 are:

14. The secondary battery according to claim 1 , wherein the cathode contains a composite oxide shown in Formula 12 as a cathode active material, Formula 12 being LiNi 1-x M x O 2 , where M is at least one of cobalt, manganese, iron, aluminum, vanadium (V), tin, magnesium (Mg), titanium, strontium (Sr), calcium (Ca), zirconium, molybdenum, technetium (Tc), ruthenium (Ru), tantalum (Ta), tungsten, rhenium (Re), ytterbium (Yb), copper, zinc, barium (Ba), boron (B), chromium, silicon, gallium (Ga), phosphorus (P), antimony, or niobium (Nb), and x is in the range of 0.005<x<0.5.

15. The secondary battery according to claim 1 , wherein the metal layer covers at least parts of surfaces of the anode active material particl

Assignees

• Hirose Takakazu
• Kawase Kenichi
• Noguchi Kazunori
• Fujii Takayuki
• Sony Corp

Inventors

• Hirose Takakazu
• Kawase Kenichi
• Noguchi Kazunori
• Fujii Takayuki

Classifications

• H01M10/0525 Primary

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/38 Primary

  of elements or alloys · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/0568

  characterised by the solutes · CPC title