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Lithium secondary battery

A lithium secondary battery and electrolyte technology, applied in secondary batteries, lithium batteries, battery electrodes, etc., can solve serious battery, cycle characteristics degradation, expansion high temperature stability and other problems

Pending Publication Date: 2021-03-05
SK ON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Metal-substituted nickel-based lithium transition metal oxides have the advantage of better cycle characteristics and capacity characteristics at room temperature, but in this case, the cycle characteristics deteriorate rapidly during long-term use at high temperatures, and cannot sufficiently solve problems such as Problems with expansion due to outgassing and low chemical stability
In particular, Li-Ni-based transition metal oxides with high Ni content generate excessive gas during storage or cycling, thereby showing severe battery swelling phenomenon and low high-temperature stability.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0224] [Example 1] Amyl difluorophosphite (CH 3 (CH 2 ) 4 OPF 2 (hereinafter referred to as "PDFP") preparation

[0225]

[0226] Step 1: Amyl dichlorophosphite (CH 3 (CH 2 ) 4 OPCl 2 ) preparation

[0227]

[0228] Tetrahydrofuran (200 mL) was added to the 500 mL flask. Phosphorus trichloride (PCl 3 ) (56mL, 0.57mol), stirred for 10 minutes, and lowered the temperature to a low temperature near 0°C using ice water. 1-Pentanol (50 g, 0.57 mol) was slowly added dropwise thereto for 30 minutes, and the solution was stirred for 3 hours while raising the temperature to room temperature. The reaction mixture was reduced to vacuum to remove volatiles. Analysis using NMR equipment to confirm residual material and final product. The final product after reduced pressure, pentyl dichlorophosphate (75 g, 0.40 mol) was obtained in 70% yield with almost 100% purity.

[0229] 1 H NMR (500MHz, C 6 D. 6 )δ0.94 (m, 3H), 1.00-1.40 (m, 6H), 3.80 (m, 2H) ppm.

[0230] Step ...

Embodiment 2

[0234] [Example 2] Preparation of (1,3-bis(allyloxy)prop-2-yl)difluorophosphite

[0235]

[0236] Step 1: (1,3-bis(allyloxy)propan-2-yl)dichlorophosphite (C 9 h 15 C l2 o 3 P) preparation

[0237]

[0238] Under a nitrogen atmosphere, 150ml of acetonitrile was added to a 500ml flask, and 37.78g (275.5mmol) of phosphorus trichloride (PCl 3 ), and the temperature was lowered to -15 °C using saline and dry ice. A mixed solution of 43.56 g (252.9 mmol) of 1,3-bis(allyloxy)propan-2-ol and 20 ml of acetonitrile was slowly added dropwise thereto for 1 hour, and the solution was stirred while raising the temperature to room temperature 3 hours. The reaction mixture was depressurized to vacuum to remove the solvent to obtain 58.85 g (215.5 mmol) of (1,3-bis(allyloxy)propan-2-yl)dichlorophosphite (C 9 h 15 C l2 o 3 P) with a yield of 85.2%.

[0239] 1 H NMR (500MHz, C 6 D. 6 )δ5.70 (m, 2H), 5.13 (d, 2H), 4.99 (d, 2H), 4.77 (m, 1H), 3.68 (m, 4H), 3.45 (m, 4H) ppm.

...

Embodiment 3- Embodiment 6

[0245] The solution was used to prepare the electrolyte by further adding the components described in Table 1 below, as the base electrolyte (1.0M LiPF 6 , EC / EMC=25:75) solution, LiPF 6 It was dissolved in a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a volume ratio of 25:75 so that the solution became a 1.0M solution.

[0246] First lithium metal oxide contained in positive electrode active material having a structure (NCM-811) including secondary particles formed by aggregating primary particles and having no concentration gradient or having a core-shell structure (CSG-811) LiNi 0.8 co 0.1 mn 0.1 o 2 , prepared in the form of the first lithium metal oxide precursor according to the following steps.

[0247] Preparation for the preparation of LiNi 0.8 co 0.1 mn 0.1 o 2 An aqueous metal solution (which has a structure including secondary particles formed by aggregating primary particles and having no concentration gradient or has a co...

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Abstract

The invention provides a lithium secondary battery, and the lithium secondary battery of the present invention includes: a positive electrode including a first lithium-metal oxide including secondaryparticles formed by aggregating primary particles having a particle diameter of 2 [mu]m or less and a second lithium-metal oxide including nickel and at least one or more metals selected from the group consisting of manganese (Mn) and cobalt (Co) and including particles having a primary particle diameter of 2 [mu]m or more; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and an electrolyte, wherein the electrolyte includes a lithium salt, a nonaqueous organic solvent, and a difluorophosphite compound containing at least one or more difluorophosphite groups.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from Korean Patent Application No. 2019-0105944 filed with the Korean Intellectual Property Office on August 28, 2019, the entire contents of which are hereby incorporated by reference in their entirety. technical field [0003] The present invention relates to a lithium secondary battery, and more particularly, to a lithium secondary battery using a positive electrode made of a positive electrode active material comprising two different A mixture of lithium metal oxides of this structure. Background technique [0004] In recent years, with the development and change of the industrial environment toward the pursuit of environmentally friendly energy, intensive research has been conducted on new energy. In particular, lithium secondary batteries that have high energy density, exhibit high performance, and also allow stable power supply as a main power source or an auxiliary power source...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/052H01M10/058H01M4/48H01M10/0566H01M10/0567H01M4/505H01M4/525
CPCH01M10/052H01M10/058H01M4/48H01M10/0566H01M10/0567H01M4/505H01M4/525H01M10/0525H01M2300/0025H01M4/131H01M4/364H01M4/366Y02E60/10Y02P70/50H01M2300/0037H01M50/46H01M10/0569H01M2004/027H01M2004/028H01M2300/0034H01M2300/0051
Inventor 都永勋李润知赵镛显赵仁行
Owner SK ON CO LTD