JP-2023183651-A - POSITIVE ELECTRODE AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY INCLUDING THE SAME

JP2023183651AJP 2023183651 AJP2023183651 AJP 2023183651AJP-2023183651-A

Abstract

To provide a positive electrode which has high energy density and high cycle characteristics and suppresses an increase in resistance during high temperature durability.SOLUTION: A positive electrode 50 disclosed herein includes: a positive electrode active material layer 54 containing a first lithium transition metal composite oxide 110 having the shape of a secondary particle and a second lithium transition metal composite oxide 120 having the shape of a single particle; and a positive electrode current collector 52. A boron compound 112 is disposed on a surface of the secondary particle of the first lithium transition metal composite oxide 110, the secondary particle having a porosity of 2-8%. An aluminum compound 121 is disposed on a surface of the single particle of the second lithium transition metal composite oxide 120. Herein, the first and second lithium transition metal composite oxides 110, 120 each have 70 mol% or more of nickel based on the total amount of transition metal elements, and the mass ratio of the first lithium transition metal composite oxide 110:the second lithium transition metal composite oxide 120 is 80:20-50:50.SELECTED DRAWING: Figure 1

Inventors

HANAZAKI AKIRA
TAKAHASHI KEIICHI

Assignees

PRIME PLANET ENERGY & SOLUTIONS INC

Dates

Publication Date: 20231228
Application Date: 20220616
Priority Date: 20220616

Claims (6)

a positive electrode current collector; a positive electrode active material layer disposed on the positive electrode current collector; A positive electrode comprising: The positive electrode active material layer is a first lithium transition metal composite oxide having a secondary particle shape in which 30 or more primary particles are aggregated; A second lithium transition metal composite oxide consisting of a single particle or a single particle formed by agglomeration of 2 to 10 primary particles, The first lithium transition metal composite oxide is A boron compound is arranged on the surface of the secondary particles, The average porosity of the secondary particles in cross-sectional observation of the secondary particles using a scanning electron microscope is 2 to 8%, The second lithium transition metal composite oxide is An aluminum compound is placed on the surface of the single particle, Here, the first and second lithium transition metal composite oxides have 70 mol% or more of nickel (Ni) based on the total amount of transition metal elements, The positive electrode has a mass ratio of the first lithium transition metal composite oxide to the second lithium transition metal composite oxide of 80:20 to 50:50.
The positive electrode according to claim 1, wherein the boron compound includes at least one selected from the group consisting of lithium borate and boron oxide.
The positive electrode according to claim 1, wherein the aluminum compound includes aluminum oxide.
The positive electrode according to claim 1, wherein at least a lithium borate salt and aluminum oxide are present on the surface of the first lithium transition metal composite oxide.
In cross-sectional observation of the secondary particles using a scanning electron microscope, the average proportion of voids observed in an area inside 1/2 of the radius of the secondary particles when viewed from the center of the secondary particles is The positive electrode according to any one of claims 1 to 4, which has 50% or more of voids in the entire secondary particles.
A positive electrode according to any one of claims 1 to 4, a negative electrode; non-aqueous electrolyte; A non-aqueous electrolyte secondary battery comprising:

Description

The present disclosure relates to a positive electrode and a nonaqueous electrolyte secondary battery including the same. In recent years, the applications of batteries have been expanding more and more, and in particular, nonaqueous electrolyte secondary batteries such as lithium ion secondary batteries are being used as portable power sources for computers, mobile terminals, etc., as well as for battery electric vehicles (BEVs) and hybrids. It is suitably used as a power source for driving vehicles such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). As non-aqueous electrolyte secondary batteries become more widespread, further improvements in performance are required. In the positive electrode of a non-aqueous electrolyte secondary battery, a lithium transition metal composite oxide is generally used as a positive electrode active material. Incidentally, in recent years, from the viewpoint of high energy density, lithium transition metal composite oxides with a high nickel content (hereinafter also referred to as "high Ni-containing lithium transition metal composite oxides") have attracted attention as positive electrode active materials. For example, Patent Document 1 describes a lithium transition metal composite oxide containing nickel at a ratio of 70 at % or more based on the total number of metal atoms other than lithium, a binder, and liquid P-CTFE (polychlorotrifluorocarbon). A positive electrode for a lithium ion secondary battery containing ethylene) is disclosed. Further, Patent Document 2 discloses a lithium ion battery positive electrode material in which the area percentage of each secondary particle is adjusted among secondary particles having different amounts of agglomeration of primary single crystal particles. JP 2017-112103 PublicationJP2019-21627A FIG. 1 is a cross-sectional view schematically showing a positive electrode according to an embodiment.FIG. 2 is a cross-sectional view schematically showing a first lithium transition metal composite oxide.1 is a vertical cross-sectional view schematically showing a lithium ion secondary battery as an example of a secondary battery obtained by a manufacturing method according to an embodiment.4 is an exploded view schematically showing an electrode body of the lithium ion secondary battery according to FIG. 3. FIG. Embodiments of the technology disclosed herein will be described below with reference to the drawings. Note that matters not mentioned in this specification, which are necessary for implementing the technology disclosed herein, can be understood as matters designed by those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the field. Furthermore, in the drawings below, members and parts that have the same functions are designated by the same reference numerals. Furthermore, the dimensional relationships (length, width, thickness, etc.) in each figure do not reflect the actual dimensional relationships. In addition, in this specification, the numerical range expressed as "A to B" includes A and B, and also includes the meanings of "preferably larger than A" and "preferably smaller than B." do. Note that in this specification, the term "secondary battery" refers to a power storage device that can be repeatedly charged and discharged, and is a term that includes so-called storage batteries and power storage elements such as electric double layer capacitors. Furthermore, in this specification, the term "lithium ion secondary battery" refers to a secondary battery that utilizes lithium ions as charge carriers and is charged and discharged by the movement of charges associated with the lithium ions between positive and negative electrodes. The term "high Ni-containing lithium transition metal composite oxide" refers to a lithium transition metal composite oxide in which the ratio of nickel (Ni) to the total amount (100 mol%) of transition metal elements is 70 mol% or more. FIG. 1 is a cross-sectional view schematically showing a positive electrode according to one embodiment. FIG. 2 is a cross-sectional view schematically showing a first lithium transition metal composite oxide according to one embodiment. As shown in FIG. 1, the positive electrode 50 according to this embodiment includes a positive electrode active material layer 54 provided on a positive electrode current collector 52. The positive electrode active material layer 54 includes a first lithium transition metal composite oxide 110 and a second lithium transition metal composite compound 120. As shown in FIG. 2, in the first lithium transition metal composite oxide 110, a boron compound 112 is disposed on the surface of the first lithium transition metal composite oxide 110. On the other hand, as shown in FIG. 1, in the second lithium-transition metal composite oxide 120, an aluminum com