KR-102963339-B1 - All Solid secondary battery, and method for preparing all solid secondary battery

KR102963339B1KR 102963339 B1KR102963339 B1KR 102963339B1KR-102963339-B1

Abstract

An all-solid-state secondary battery is presented, comprising: an anode layer including an anode active material layer; a cathode layer; and a solid electrolyte layer disposed between the anode layer and the cathode layer and including a solid electrolyte, wherein the cathode layer comprises: a cathode current collector; a first cathode active material layer disposed on the cathode current collector and in contact with the solid electrolyte layer; and a second cathode active material layer disposed between the cathode current collector and the first cathode active material layer, wherein the first cathode active material layer comprises a first carbon-based cathode active material and the second cathode active material layer comprises a second carbon-based cathode active material, and the intensity ratio of the D band peak and the G band peak in the Raman spectrum of the first carbon-based cathode active material I 1 D / I 1 G is lower than the intensity ratio of the second carbon-based cathode active material I 2 D / I 2 G.

Inventors

김주식
김세원
로에브 빅터
이명진
류새봄
임동민

Assignees

삼성전자주식회사

Dates

Publication Date: 20260511
Application Date: 20210127
Priority Date: 20200218

Claims (20)

A positive electrode layer comprising a positive electrode active material layer; a negative electrode layer; and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer and comprising a solid electrolyte, The above cathode layer comprises a cathode current collector; a first cathode active material layer in contact with the solid electrolyte layer; and a second cathode active material layer disposed between the cathode current collector and the first cathode active material layer. The first negative electrode active material layer comprises a first carbon-based negative electrode active material, and the second negative electrode active material layer comprises a second carbon-based negative electrode active material. The intensity ratio of the D band peak to the G band peak in the Raman spectrum of the first carbon-based negative electrode active material , I1D / I1G , is lower than the intensity ratio of I2D / I2G of the second carbon-based negative electrode active material , and The intensity ratio of the D band peak to the G band peak in the Raman spectrum of the first carbon-based negative electrode active material , I1D / I1G , is 0.5 to 0.95, and An all-solid-state secondary battery in which the intensity ratio of the D band peak to the G band peak in the Raman spectrum of the second carbon-based negative electrode active material , I2D / I2G , is 1.0 or greater.
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In claim 1, the position of the center of the D band peak in the Raman spectrum of the first carbon-based negative electrode active material is blue shifted by more than 2.0 cm⁻¹ compared to the position of the center of the D band peak in the Raman spectrum of the second carbon-based negative electrode active material, The position of the center of the G band peak in the Raman spectrum of the first carbon-based negative electrode active material is blue shifted by more than 1.0 cm⁻¹ compared to the position of the center of the G band peak in the Raman spectrum of the second carbon-based negative electrode active material, and All-solid-state secondary battery in which the width of the D-band peak in the Raman spectrum of the first carbon-based negative electrode active material is 80% or less compared to the width of the D-band peak in the Raman spectrum of the second carbon-based negative electrode active material.
In claim 1, one or more of the first carbon-based negative electrode active material and the second carbon-based negative electrode active material have a particle form, and All-solid-state secondary battery having an average particle size of at least one of the first carbon-based negative electrode active material particles and the second carbon-based negative electrode active material of 4 µm or less.
A solid-state secondary battery according to claim 1, wherein one or more of the first carbon-based negative electrode active material and the second carbon-based negative electrode active material comprise amorphous carbon.
A solid-state secondary battery according to claim 1, wherein one or more of the first negative electrode active material layer and the second negative electrode active material layer are made of a carbon-based material.
A solid-state secondary battery according to claim 1, wherein one or more of the first negative electrode active material layer and the second negative electrode active material layer further comprise a metal or metal negative electrode active material.
The all-solid-state secondary battery according to claim 7, wherein the metal or metalloid negative electrode active material comprises one or more selected from indium (In), silicon (Si), gallium (Ga), tin (Sn), aluminum (Al), titanium (Ti), zirconium (Zr), niobium (Nb), germanium (Ge), antimony (Sb), bismuth (Bi), gold (Au), platinum (Pt), palladium (Pd), magnesium (Mg), palladium (Pd), silver (Ag), and zinc (Zn).
In claim 7, the first cathode active material layer comprises a composite of a first particle made of amorphous carbon and a second particle made of a metal or metalloid, and A solid-state secondary battery in which the content of the second particle is 1 to 60 weight% based on the total weight of the composite.
In claim 7, the second cathode active material layer comprises a mixture of first particles made of amorphous carbon and second particles made of metal or metalloid, and A solid-state secondary battery in which the content of the second particle is 1 to 60 weight% based on the total weight of the mixture.
In claim 7, the content of the metal or metalloid cathode active material included in the second cathode active material layer and the content of the metal or metalloid cathode active material included in the first cathode active material layer are different from each other, A solid-state secondary battery in which the content of the metal or metalloid cathode active material included in the second cathode active material layer is higher than the content of the metal or metalloid cathode active material included in the first cathode active material layer.
In claim 1, the first cathode active material layer comprises a composite of a first particle made of amorphous carbon and a second particle made of a metal or metalloid, and The second negative electrode active material layer comprises a mixture of first particles made of amorphous carbon and second particles made of metal or metalloid, and The average particle size of the first particle included in the second negative electrode active material layer is 50% or less of the average particle size of the first particle included in the first negative electrode active material layer, and An all-solid-state secondary battery in which the average particle size of the second particles included in the second negative electrode active material layer is 50% or less of the average particle size of the second particles included in the first negative electrode active material layer.
A solid-state secondary battery according to claim 1, wherein the first carbon-based negative electrode active material forms one or more of a covalent bond and an ionic bond with the solid electrolyte.
A solid-state secondary battery according to claim 1, wherein the first negative electrode active material layer does not include an organic material.
A solid-state secondary battery according to claim 1, wherein the first carbon-based negative electrode active material is a sintered product of a carbon-based precursor, and the carbon-based precursor is the second carbon-based negative electrode active material.
In claim 1, the thickness of the first negative electrode active material layer is 50% or less of the thickness of the positive electrode active material layer, and All-solid-state secondary battery having a thickness of 10 nm to 10 µm of the first negative electrode active material layer.
In claim 1, the thickness of the second negative electrode active material layer is 50% or less of the thickness of the positive electrode active material layer, and All-solid-state secondary battery having a thickness of 1 µm to 50 µm of the second negative electrode active material layer.
A solid-state secondary battery according to claim 1, wherein the thickness of the first negative electrode active material layer is thinner than the thickness of the second negative electrode active material layer.
A solid-state secondary battery according to claim 1, wherein one or more of the first negative electrode active material layer and the second negative electrode active material layer further comprise a binder.
A solid-state secondary battery according to claim 1, wherein the second negative electrode active material layer comprises a second carbon-based negative electrode active material and a metal or metalloid negative electrode active material, and the first negative electrode active material layer is made of a carbon-based material.

Description

All Solid secondary battery, and method for preparing all solid secondary battery This relates to an all-solid-state secondary battery and a method for manufacturing the same. Recently, driven by industrial demands, the development of batteries with high energy density and safety is actively underway. For example, lithium-ion batteries are being commercialized not only in the fields of information and communication devices but also in the automotive sector. In the automotive sector, safety is considered particularly important because it is directly related to human life. Currently commercially available lithium-ion batteries use electrolytes containing flammable organic solvents, so there is a possibility of overheating and fire in the event of a short circuit. In response to this, all-solid-state batteries using a solid electrolyte instead of an electrolyte are being proposed. By not using flammable organic solvents, all-solid-state batteries can significantly reduce the likelihood of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can offer significantly higher safety compared to lithium-ion batteries that use liquid electrolytes. FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an exemplary embodiment. FIG. 2 is a cross-sectional view of an all-solid-state secondary battery according to an exemplary embodiment. FIG. 3 is a cross-sectional view of an all-solid-state secondary battery according to an exemplary embodiment. FIG. 4 is a cross-sectional view of an all-solid-state secondary battery according to an exemplary embodiment. Figure 5a is an SEM image of the surface of the precursor layer, which is the dried product before heat treatment at 450°C in Example 1. Figure 5b is an SEM image of the surface of the first cathode active material layer obtained after heat treatment at 450°C in Example 1. Figure 6a is an SEM image of a cross-section of a solid electrolyte layer/first cathode active material layer laminate prepared in Example 1. FIG. 6b is an EDX (Energy-Dispersive X-ray spectroscopy) carbon mapping image of a cross- section of the solid electrolyte layer/first cathode active material layer laminate prepared in Example 1. FIG. 7a is a scanning electron microscope (SEM) image of the surface of the first cathode active material layer obtained in Example 2. Figure 7b is a silver mapping image of the surface of the first cathode active material layer prepared in Example 2 using EDX (Energy-Dispersive X-ray spectroscopy). Figure 7c is an EDX (Energy-Dispersive X-ray spectroscopy) carbon mapping image of the surface of the first cathode active material layer prepared in Example 2. FIG. 8a is a scanning electron microscope (SEM) image of a cross- section of a solid electrolyte layer/cathode layer laminate prepared in Example 2. FIG. 8b is a partial enlarged view of the cross-section of the interface region between the solid electrolyte layer and the first cathode active material layer in FIG. 8a. FIG. 8c is a partial enlarged view of the cross-section of the interface region between the first cathode active material layer and the second cathode active material layer in FIG. 8a. FIG. 8d is a partial enlarged view of the cross-section of the inner region of the second cathode active material layer in FIG. 8a. FIG. 8e is an XRD diffraction pattern for the first cathode active material layer adjacent to the solid electrolyte layer in FIG. 8a. FIG. 8f is an XRD diffraction pattern for a second cathode active material layer adjacent to a first cathode active material layer in FIG. 8a. Figure 8g is the XRD diffraction pattern for the region inside the second cathode active material layer in Figure 8a. FIG. 8h is an EDX (Energy-Dispersive X-ray spectroscopy) carbon mapping image of a cross- section of the first cathode active material layer adjacent to the solid electrolyte layer in FIG. 8a. FIG. 8i is an EDX (Energy-Dispersive X-ray spectroscopy) carbon mapping image of a cross-section of a second cathode active material layer adjacent to the first cathode active material layer in FIG. 8a. Figure 8j is an EDX (Energy-Dispersive X-ray spectroscopy) carbon mapping image of a cross-section of a certain area inside the second cathode active material layer in Figure 8a. Figure 9a is the Raman spectrum of the surface of the precursor layer (i.e., the second negative active material layer) which is the dried product before heat treatment at 450°C in Example 1. Figure 9b is a Raman spectrum image of the surface of the first cathode active material layer obtained after heat treatment at 450°C in Example 1. FIG. 10 is a Nyquist plot showing the impedance measurement results for the all-solid-state secondary batteries prepared in Comparative Example 1 and Comparative Example 2. Figure 11a is the charge/discharge profile of the all-solid-state secondary battery manufactured in Example 1. Figure 11b is the charge/discharge profile of the all