Nonaqueous lithium-type power storage element

Patent metadata

Field	Value
Publication number	US-10748716-B2
Application number	US-201916377407-A
Country	US
Kind code	B2
Filing date	Apr 8, 2019
Priority date	Jan 22, 2016
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

Provided is a nonaqueous lithium-type power storage element in which a lithium compound is included in positive electrode, wherein energy loss due to voltage decrease under high temperatures and high voltages is reduced, and the high-load charge and discharge cycle characteristics are exceptional.

First claim

What is claimed is:

1. A method for producing a nonaqueous lithium-type storage element, the method comprising the steps of:
providing a positive electrode precursor, comprising a positive electrode power collector, and a positive electrode active material layer located at one surface or both surfaces of the positive electrode power collector, wherein the positive electrode active material layer comprises a positive electrode active material, a lithium compound other than the positive electrode active material, and a solvent;
providing a negative electrode, comprising a negative electrode power collector, and a negative electrode active material layer located at one surface or both surfaces of the negative electrode power collector, wherein the negative electrode active material layer comprises a negative electrode active material, and a solvent;
laminating the positive electrode precursor and the negative electrode via a separator to provide an electrode laminated body, or rolling the positive electrode precursor and the negative electrode via a separator to provide an electrode roll; and
drying the electrode laminated body or the electrode roll, so that the amount of the solvent remaining in the positive electrode active material layer or the negative electrode active material layer is less than or equal to 1.5 weight % based on the total weight of the positive electrode active material layer or the negative electrode active material layer.

2. The method according to claim 1 , further comprising after the drying step, the steps of:
placing the electrode laminated body or the electrode roll in a casing, injecting a nonaqueous electrolytic solution containing lithium ions in the casing, and encapsulating the casing; and
pre-doping lithium ions to the negative electrode active material layer, by decomposition of the lithium compound in the positive electrode precursor, by applying voltage between the positive electrode precursor and the negative electrode, releasing lithium ions, and reducing lithium ions at the negative electrode.

3. The method according to claim 2 , further comprising performing a charging and discharging cycle after the pre-doping step.

4. The method according to claim 3 , wherein the charging and discharging cycle is performed between a voltage of 2.0 V and 4.0 V.

5. The method according to claim 4 , wherein the nonaqueous lithium-type storage element comprises (a) a positive electrode including the positive electrode power collector, the positive electrode active material layer located at one surface or both surfaces of the positive electrode power collector, and containing the positive electrode active material and the lithium compound other than the positive electrode active material, (b) the negative electrode, (c) the separator, and (d) the nonaqueous electrolytic solution containing lithium ions,
wherein the nonaqueous lithium-type storage element satisfies:
2≤C≤300, where C (ppm) is concentration of Na and/or K element, contained in the positive electrode active material layer, and
1.0≤D≤15, 10≤E≤100, 0.2≤C/D≤38, and 0.1≤C/E≤7.2, where D (g/m 2 ) is basis weight of the lithium compound other than the positive electrode active material, contained in the positive electrode active material layer, per one surface of the positive electrode, and E (g/m 2 ) is basis weight of the positive electrode active material contained in the positive electrode active material layer, per one surface of the positive electrode.

6. The method according to claim 5 , wherein the lithium compound is lithium carbonate.

7. The method according to claim 5 , wherein the concentration C is 2.5≤C≤300.

8. The method according to claim 5 , wherein 0.01≤D/E≤0.52.

9. The method according to claim 5 , wherein A 1 is 40% to 99%, where A 1 is area overlap ratio of fluorine mapping to oxygen mapping, binarized based on average value of brightness, in an element mapping obtained using SEM-EDX of the surface of the positive electrode.

10. The method according to claim 5 , wherein A 2 is 10% to 60%, where A 2 is area overlap ratio of fluorine mapping to oxygen mapping, binarized based on average value of brightness, in the element mapping obtained using SEM-EDX of the cross-section of the BIB processed positive electrode.

11. The method according to claim 5 , wherein
(h) Fe/F is 1.01 or higher,
where Fe (F) is static capacitance after carrying out charging and discharging cycle 60,000 times under an environmental temperature of 25° C., a cell voltage of from 2.2 V to 3.8 V, a rate of an electric current value of 200 C, and subsequently carrying out charging under a constant voltage of 4.5 V for 1 hour, and F (F) is static capacitance before the charging and discharging cycle, for the nonaqueous lithium-type storage element.

12. The method according to claim 11 , wherein the nonaqueous electrolytic solution in the nonaqueous lithium-type storage element further contains a lithium salt of
(A) at least one of LiPF 6 and LiBF 4 ; as well as
(B) at least one of LiN(SO 2 F) 2 , LiN(SO 2 CF 3 ) 2 , and LiN(SO 2 C 2 F 5 ) 2 .

13. The method according to claim 12 , wherein molar concentration ratio M A /(M A +M B ) is in a range of from 1/10 to 9/10, where M A (mol/L) is the total molar concentration of the (A), and M B (mol/L) is the total molar concentration of the (B), based on the total amount of the nonaqueous electrolytic solution in the nonaqueous lithium-type storage element.

14. The method according to claim 13 , wherein molar concentration ratio M A /M B of the lithium salt is in a range of from 2/10 to 6/10.

15. The method according to claim 12 , wherein the total molar concentration M B (mol/L) of the (B) is 0.1 mol/L to 1.5 mol/L.

16. The method according to claim 12 , wherein the (A) is LiPF 6 , and the (B) is LiN(SO 2 F) 2 .

17. The method according claim 5 , wherein the positive electrode precursor comprises the positive electrode active material layer containing the positive electrode active material containing activated carbon, and the lithium compound other than the positive electrode active material, wherein 20≤C 0 ≤1300 ppm, where C 0 (ppm) is concentration of Na and/or K element contained in the positive electrode active material layer of the positive electrode precursor; 8.0≤D 0 ≤50.0, where D 0 (g/m 2 ) is basis weight of the lithium compound other than the positive electrode active material contained in the positive electrode active material layer, per one surface of the positive electrode precursor;10≤E 0 ≤100, 0.2≤C 0 /D 0 ≤38, and 0.1≤C 0 /E 0 ≤7.2, where E 0 (g/m 2 ) is basis weight of the positive electrode active material contained in the positive electrode active material layer, per one surface of the positive electrode precursor.

18. The method according to claim 5 , wherein the nonaqueous lithium-type storage element satisfies 1.00≤C 1 /C 2 ≤15.00, where C 1 (ppm) is concentration of Na and/or K element contained in the negative electrode active material layer, and C 2 (ppm) is concentration of Na and/or K element contained in the electrolytic solution,
the lithium compound is one or more compounds selected from lithium carbonate, lithium oxide, lithium hydroxide, lithium fluoride, lithium chloride, lithium bromide, lithium iodide, lithium nitride, lithium oxalate, and lithium acetate, and
wherein the nonaqueous lithium-type storage element satisfies 0.1 μm≤X 1 ≤10 μm, where X 1 is average particle diameter of the lithium compound, 2 μm≤Y 1 ≤20 μm, and X 1 <Y 1 , where Y 1 is average particle diameter of the positive electro

Assignees

• Asahi Chemical Ind

Inventors

• Umetsu Kazuteru
• Hirakawa Yuichiro
• Kimura Yuima
• Morita Hitoshi
• Okada Nobuhiro

Classifications

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01G11/62

  characterised by the solute, e.g. salts, anions or cations therein · CPC title

• H01G11/60

  characterised by the solvent · CPC title

• H01G11/30

  characterised by their material · CPC title

• H01G11/24

  characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor · CPC title