Lithium-ion secondary battery and method for producing the same

Patent metadata

Field	Value
Publication number	US-9590237-B2
Application number	US-201414769750-A
Country	US
Kind code	B2
Filing date	Jan 8, 2014
Priority date	Feb 25, 2013
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A lithium-ion secondary battery of the present invention comprises a positive electrode including a positive electrode active material composite formed by compositing a lithium silicate-based material and a carbon material, a negative electrode including a negative electrode active material containing a silicon, and an electrolyte. The lithium-ion secondary battery satisfies 0.8<B/A<1.2, where A is irreversible capacity of the positive electrode and B is irreversible capacity of the negative electrode.

First claim

The invention claimed is:

1. A lithium-ion secondary battery, comprising a positive electrode including a positive electrode active material composite formed by compositing a lithium silicate-based material and a carbon material, a negative electrode including a negative electrode active material containing a silicon, and an electrolyte, and
satisfying 0.8<B/A<1.2, where A is irreversible capacity of the positive electrode and B is irreversible capacity of the negative electrode.

2. The lithium-ion secondary battery according to claim 1 , satisfying 0.8<D/C<1.2, where C is reversible capacity of the positive electrode and D is reversible capacity of the negative electrode.

3. The lithium-ion secondary battery according to claim 1 , wherein the positive electrode active material composite is formed by compositing the lithium silicate-based material and the carbon material by mechanical milling of the lithium silicate-based material and the carbon material.

4. The lithium-ion secondary battery according to claim 3 , wherein the irreversible capacity of the positive electrode is adjusted by controlling at least one of milling speed and milling time of the mechanical milling.

5. The lithium-ion secondary battery according to claim 1 , wherein the lithium silicate-based material is expressed by a compositional formula Li 2+a−b A b M 1−β M′ β Si 1+α O 4+c , where A is at least one element selected from the group consisting of Na, K, Rb, and Cs, M is at least one element selected from the group consisting of Fe and Mn, and M′ is at least one element selected from the group consisting of Mg, Ca, Co, Al, Ni, Nb, Ti, Cr, Cu, Zn, Zr, V, Mo and W, and the subscripts are as follows: 0≦α≦0.2, 0≦β≦0.5, 0≦a<1, 0≦b<0.2, 0<c<0.3.

6. The lithium-ion secondary battery according to claim 1 , wherein the amount of the carbon material contained in the positive electrode active material composite is not less than 1% by mass and not more than 50% by mass of the total mass of the positive electrode active material composite.

7. The lithium-ion secondary battery according to claim 1 , wherein
the negative electrode active material comprises at least one of Si and SiO x , and
the SiO x has an overall composition expressed by a formula: SiO x (0.5≦x≦1.5) and comprises Si phase and SiO 2 phase.

8. The lithium-ion secondary battery according to claim 1 , wherein the negative electrode active material is synthesized from Si powder and the lithium silicate-based material of the positive electrode active material has an average particle size of not less than 10 nm and not more than 10 μm, and the carbon material of the positive electrode active material has an average particle size of not less than 10 nm and not more than 1 μm.

9. The lithium-ion secondary battery according to claim 1 , wherein the negative electrode active material is synthesized from SiO x powder and the lithium silicate-based material of the positive electrode active material has an average particle size of not less than 10 nm and not more than 20 μm, and the carbon material of the positive electrode active material has an average particle size of not less than 10 nm and not more than 1 μm.

10. A method for producing a lithium-ion secondary battery having a positive electrode including a positive electrode active material composite formed of compositing a lithium silicate-based material and a carbon material, a negative electrode including a negative electrode active material containing a silicon, and an electrolyte;
forming the positive electrode active material composite by compositing the lithium silicate-based material and the carbon material by mechanical milling of the lithium silicate-based material and the carbon material; and satisfying 0.8<B/A<1.2, where A is irreversible capacity of the positive electrode and B is irreversible capacity of the negative electrode.

11. The method for producing a lithium-ion secondary battery according to claim 10 , wherein the irreversible capacity of the positive electrode is adjusted by controlling at least one of milling speed and milling time of the mechanical milling.

Assignees

• Toyota Jidoshokki Kk
• Nat Inst Advanced Ind Science & Tech

Inventors

• Kojima Akira
• Niwa Junichi
• Kawasumi Kazuhito
• IKEUCHI Yuta
• Morishita Masanori
• Kojima Toshikatsu
• Sakai Tetsuo

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M10/0525

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