Layered cathode
By designing the structure of the ion transport layer and electron transport layer in the NMC cathode of a sulfide-based solid state battery, the problem of resistive interface layer formation caused by the reaction of the NMC cathode with LPSC is solved, the energy density and cycle life of the battery are improved, and carbon additives are allowed to be stably included.
Patent Information
- Application Number
- CN202411738118.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-11
- Filing Date
- 2024-11-29
- Publication Date
- 2025-06-20
AI Technical Summary
In a sulfide-based solid state battery (SSB) containing lithium silver ore (Li6PS5Cl or LPSC) sulfide solid electrolyte, the reaction of the NMC cathode with the LPSC leads to the formation of a resistive interface layer, affecting capacity and cycle life.
A cathode structure is designed, including an ion transport layer and an electron transport layer. The ion transport layer consists of a homogeneous mixture of lithium silver ore particles and NMC particles coated with lithium ceramics, and the electron transport layer consists of uncoated NMC particles and contains lithium silver ore particles and carbon additives in a certain proportion (about 10:90).
With this structure, the energy density and output performance of the battery are improved, side reactions are reduced, cycle life is extended, and carbon additives are allowed to be stably included to improve conductivity.
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Figure CN120184172A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a cathode structure for a solid-state battery cell. Background Art
[0002] In the field of energy storage, sulfide-based solid-state batteries (SSBs) with cathodes based on nickel manganese cobalt (NMC) are used due to their energy density, thermal stability, specific capacity, and performance at high voltages in lithium-ion batteries. However, cathodes used in SSBs containing a lithiophosphate (Li6PS5Cl or LPSC) sulfide solid electrolyte can react with NMC, resulting in the formation of a resistive interfacial layer. These layers can cause capacity fade during the initial charge or discharge cycle.
[0003] For conventional lithium-ion batteries, adding a carbon additive to the cathode is a well-recognized method to improve conductivity. Extending this concept to NMC cathodes in sulfide-based SSBs, carbon additives have been considered to enhance conductivity. However, this solution introduces new problems. Carbon additives tend to react with LPSC particles, thereby affecting LPSC. This reaction can lead to capacity fade and shortened cycle life. Summary of the Invention
[0004] A battery electrode includes: a homogeneous layer of lithiophosphate particles and nickel manganese cobalt oxide (NMC) particles coated with a lithium ceramic for forming an ion transport layer; and an additional layer of uncoated NMC particles that defines an electron transport layer, thereby forming a cathode when in contact with the ion transport layer. The electron transport layer can be sulfide-based or include lithiophosphate particles. In one embodiment, the ratio of lithiophosphate particles to uncoated NMC particles is about 10:90. The electron transport layer can also contain a carbon additive, and the lithium ceramic coating on the NMC particles can be Li4Ti5O 12 or LiNbO3.
[0005] A method for forming a cathode involves applying and curing a homogeneous slurry of lithiophosphate particles and NMC particles, followed by a layer of uncoated NMC particles, onto a current collector. The lithium ceramic coating on the NMC particles in the method can be applied using a sol-gel process and can be Li4Ti5O 12 or LiNbO3. The slurry applied to the homogeneous layer can have a specific ratio of lithiophosphate particles to NMC particles of about 10:90.
[0006] A solid-state battery cell is described, which includes an anode, a cathode having different ion-conductive layers and electron-conductive layers, and a solid electrolyte between the anode and the ion-conductive layer. The cell may include a pair of current collectors sandwiching the anode, the solid electrolyte, and the cathode. The electron-conductive layer may contain a carbon additive, be sulfide-based, or include lithiated garnet particles and uncoated NMC particles, where the specific ratio of lithiated garnet particles to uncoated NMC particles is about 10:90. The ion-conductive layer may include NMC particles coated with a lithium ceramic, and the NMC particles coated with a lithium ceramic include a homogeneous mixture of lithiated garnet particles and NMC particles coated with a lithium ceramic, and the NMC particles coated with a lithium ceramic may be coated with Li4Ti5O 12 or LiNbO3. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 is a schematic diagram of a battery cell according to one embodiment;
[0008] Figure 2 is a schematic diagram of a battery electrode according to one embodiment; and
[0009] Figure 3 is a flowchart of an assembly process according to one embodiment. DETAILED DESCRIPTION
[0010] Embodiments are described herein. However, it is to be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The drawings are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Accordingly, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching one of ordinary skill in the art.
[0011] The various features shown and described in any one of the reference drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. Combinations of the features shown provide representative embodiments for typical applications. However, for a particular application or implementation, various combinations and modifications of the features may be desirable that are consistent with the teachings of this disclosure.
[0012] This disclosure relates to the assembly and composition of sulfide-based solid-state batteries (SSBs), particularly cathode composition and design. Utilizing the layered oxide LiNi x Mn y Co 1-xySulfide-based SSBs with O2(NMC) as the cathode material can have potential advantages over conventional lithium-ion batteries, especially in terms of energy density. However, when NMC is used as a solid electrolyte together with sulfide-based argyrodite (Li6PS5Cl or LPSC), the instability of LPSC in the presence of NMC leads to side reactions that may reduce the effectiveness of NMC in lithium-ion intercalation and produce by-products at the cathode and separator interface.
[0013] A cathode structure including two different layers is proposed. The first layer, called the ion transport layer, is located at the interface between the cathode and the solid electrolyte. This layer can include a homogeneous mixture of NMC and LPSC particles, with a ratio that may be 50:50. The NMC particles in this layer can be coated with a lithium-containing material applied through a sol-gel process, such as a Li2O-based solid solution, Li4Ti5O 12 or LiNbO3. This coating can promote lithium-ion conduction while preventing electron conduction.
[0014] Compared with the second layer, the ion transport layer includes large NMC particle sizes (about 10 μm average particle diameter). This size difference is intended to promote the diffusion of lithium ions into the cathode, thereby theoretically increasing the energy density and output of the battery. The second layer, called the electron transport layer, is located between the current collector and the ion transport layer. The electron transport layer can include NMC and LPSC particles in a ratio of 90:10. The reduced presence of LPSC in this layer can allow for the stable inclusion of carbon additives that are mixed with the NMC particles to increase the conductivity at the cathode and current collector interface. These additives can help improve the charging rate of the battery. In this layer, the NMC particles are generally not coated to maintain conductivity, which may be a consideration for direct current (DC) fast charging applications.
[0015] The layered cathode composition can be assembled through two consecutive slot die coating operations. The first operation involves coating the electron transport layer onto the current collector, followed by applying the ion transport layer onto the electron transport layer.
[0016] Figure 1Shows a schematic diagram of a solid-state battery cell 10 according to an embodiment. The anode current collector 12 is located at the topmost section of the battery cell 10. The anode current collector 12 facilitates the collection and distribution of electrons at the anode end during charging and discharging cycles. The design of the anode current collector 12 is optimized for efficient electron flow, thus contributing to the overall performance of the battery. The anode 14 is directly below the anode current collector 12. The anode layer 14 accommodates lithium ions during the discharge phase of the battery, thus affecting the energy capacity of the battery cell 10. Below the anode layer 14 is the solid electrolyte 16, which is a sulfide-based solid electrolyte and is in direct contact between the anode 14 and the ion-conducting layer 18. The solid electrolyte 16 facilitates ion conduction while preventing electron flow.
[0017] The ion-conducting layer 18 comprises a homogeneous mixture of lithium garnet particles and lithium nickel manganese cobalt oxide particles, or lithium garnet particles and lithium nickel manganese cobalt oxide particles in a ratio of 50:50. The nickel manganese cobalt oxide particles may be coated with a lithium ceramic, such as Li4Ti5O 12 or LiNbO3. This forms a homogeneous layer defining the ion transport layer 18. The ion-conducting layer 18 facilitates the movement of lithium ions within the battery cell 10. Below the ion-conducting layer 18 is the electron-conducting layer 20. The adjacent electron-conducting layer 20 comprises lithium garnet particles and uncoated nickel manganese cobalt oxide particles in a ratio of 10:90. The electron-conducting layer 20 may also contain a carbon additive. The electron conduction layer 20 facilitates electron conduction. The cathode current collector 22 is positioned at the bottom of the battery cell 10. The cathode current collector facilitates the external flow of electrons, thus completing the circuit of the battery cell. The solid-state battery cell 10 is sandwiched between a pair of current collectors 12 and 22, with the anode current collector 12 at the top and the cathode current collector 22 at the bottom.
[0018] Figure 2 Shows a schematic diagram of a battery electrode 24. The battery electrode 24 has an ion transport layer 26 on top of the electron transport layer 28. The corresponding layers contain lithium garnet particles 30 and nickel manganese cobalt (NMC) oxide particles 32. The ion transport layer 26 comprises a homogeneous mixture of lithium garnet particles 30 and NMC oxide particles 32. In the ion transport layer 26, the nickel manganese cobalt oxide particles 32 may be coated with a lithium ceramic 34. The lithium ceramic coating 34 may be Li4Ti5O 12 or LiNbO3. The electron transport layer 28 having a different material composition from the ion transport layer 26 comprises lithium garnet particles 30 and uncoated NMC oxide particles 32 in a ratio of approximately 10:90. The electron transport layer 28 may be sulfide-based. In some configurations, the electron transport layer 28 may contain a carbon additive 36.
[0019] Figure 3FIG. is a diagrammatic illustration of a flowchart of an assembly process according to an embodiment. In block 38, a homogeneous slurry is prepared, the homogeneous slurry including litharge particles and nickel manganese cobalt oxide (NMC) particles. The NMC particles in the slurry may be coated with a lithium ceramic, which may be Li4Ti5O 12 or LiNbO3. The slurry is then uniformly applied to a current collector. After the slurry is applied in block 40, the slurry undergoes a curing process. Curing causes the slurry to solidify into a homogeneous layer that adheres to the current collector. This layer serves as a base layer for subsequent steps.
[0020] In block 42, a second slurry is applied. The slurry includes uncoated NMC particles. The ratio of litharge particles to NMC particles in the slurry may be about 10:90. In block 44, the second slurry layer is also subjected to a curing process. This step causes the layer to solidify and integrate it with the underlying homogeneous layer. The result is a bilayer cathode. Coating of the NMC particles with the lithium ceramic may be accomplished via a sol-gel process. Suitable lithium ceramics may be Li4Ti5O 12 or LiNbO3.
[0021] The algorithms, methods, or processes disclosed or proposed herein may be conveyed to or implemented by a computer, controller, or processing device, which may include any dedicated electronic control unit or programmable electronic control unit. Similarly, the algorithms, methods, or processes may be stored in various forms as data and instructions executable by a computer or controller, including but not limited to information permanently stored on a non-writable storage medium such as a read-only memory device and information alterably stored on a writable storage medium such as an optical disk, random access memory device, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented as software-executable objects. Alternatively, suitable hardware components, such as application specific integrated circuits, field programmable gate arrays, state machines, or other hardware components or devices, or firmware, or a combination of hardware and software components, may be used to implement all or part of the algorithms, methods, or processes.
[0022] Although the above describes exemplary embodiments, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive words rather than limiting words, and it should be understood that various changes may be made without departing from the spirit and scope of the disclosed materials.
[0023] As previously described, the features of the various embodiments can be combined to form additional embodiments that may not be explicitly described or shown in the present disclosure. Although the various embodiments may have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve the desired overall system attributes, depending on the particular application and implementation. These attributes may include, but are not limited to: strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Thus, embodiments that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are within the scope of the present disclosure and may be desirable for a particular application.
[0024] According to the present invention, there is provided a battery electrode having: a homogeneous layer of lithiated silver vanadate particles and nickel manganese cobalt oxide (NMC) particles coated with a lithium ceramic, which defines an ion transport layer; and a layer comprising uncoated nickel manganese cobalt oxide particles, which defines an electron transport layer in contact with the ion transport layer to form a cathode.
[0025] According to one embodiment, the electron transport layer is sulfide-based.
[0026] According to one embodiment, the electron transport layer comprises lithiated silver vanadate particles.
[0027] According to one embodiment, the ratio of lithiated silver vanadate particles to uncoated nickel manganese cobalt oxide particles is about 10:90.
[0028] According to one embodiment, the electron transport layer further contains a carbon additive.
[0029] According to one embodiment, the nickel manganese cobalt oxide particles coated with a lithium ceramic are coated with Li4Ti5O 12 or LiNbO3.
[0030] According to the present invention, a method includes: applying a homogeneous slurry of lithiated silver vanadate particles and nickel manganese cobalt oxide particles coated with a lithium ceramic to a current collector; curing the homogeneous slurry to form a homogeneous layer; applying a slurry comprising uncoated nickel manganese cobalt oxide particles to the homogeneous layer; and curing the slurry to form a cathode.
[0031] In one aspect of the present invention, the method includes coating nickel manganese cobalt oxide particles with a lithium ceramic via a sol-gel process to form nickel manganese cobalt oxide particles coated with a lithium ceramic.
[0032] In one aspect of the present invention, the lithium ceramic is Li4Ti5O 12 or LiNbO3.
[0033] In one aspect of the present invention, a slurry comprising uncoated nickel manganese cobalt oxide particles further comprises lithium silver oxide particles and nickel manganese cobalt oxide particles in a ratio of about 10:90.
[0034] According to the present invention, there is provided a solid-state battery cell having: an anode; a cathode including an ion-conductive layer and an adjacent electron-conductive layer having a different material composition from the ion-conductive layer; and a solid electrolyte between the anode and the ion-conductive layer and in direct contact with the anode and the ion-conductive layer such that the ion-conductive layer is between the solid electrolyte and the electron-conductive layer.
[0035] According to one embodiment, the anode, the solid electrolyte, and the cathode are sandwiched between a pair of current collectors.
[0036] According to one embodiment, the electron-conductive layer further comprises a carbon additive.
[0037] According to one embodiment, the electron-conductive layer is sulfide-based.
[0038] According to one embodiment, the electron-conductive layer includes lithium silver oxide particles.
[0039] According to one embodiment, the electron-conductive layer includes uncoated nickel manganese cobalt oxide particles.
[0040] According to one embodiment, the ratio of lithium silver oxide particles to uncoated nickel manganese cobalt oxide particles is about 10:90.
[0041] According to one embodiment, the ion-conductive layer includes nickel manganese cobalt oxide particles coated with a lithium ceramic.
[0042] According to one embodiment, the ion-conductive layer includes a homogeneous mixture of lithium silver oxide particles and nickel manganese cobalt oxide particles coated with a lithium ceramic.
[0043] According to one embodiment, the nickel manganese cobalt oxide particles coated with a lithium ceramic are coated with Li4Ti5O 12 or LiNbO3.
Claims
1. A battery electrode, comprising: a homogenous layer of lithiolate particles and nickel manganese cobalt oxide particles coated with lithium ceramic defining an ion transport layer; as well as A layer comprising uncoated nickel manganese cobalt oxide particles defining an electron transport layer in contact with the ion transport layer to form a cathode.
2. The battery electrode of claim 1, wherein the electron transport layer is sulfide-based.
3. The battery electrode of claim 1, wherein the electron transport layer comprises heliotropy particles.
4. The battery electrode of claim 3, wherein the ratio of the heliotrope particles to the uncoated nickel manganese cobalt oxide particles is about 10:
90.
5. The battery electrode of claim 1, wherein the electron transport layer further comprises a carbon additive.
6. The battery electrode as claimed in claim 1, wherein the nickel manganese cobalt oxide particles coated with lithium ceramic are coated with Li4Ti5O 12 or LiNbO3.
7. A method comprising: applying a homogenous slurry of niobium ore particles and nickel manganese cobalt oxide particles coated with lithium ceramic to a current collector; solidifying the homogenous slurry to form a homogenous layer; applying a slurry including uncoated nickel manganese cobalt oxide particles to the homogenous layer; as well as The slurry is cured to form a cathode.
8. The method of claim 7, comprising coating nickel manganese cobalt oxide particles with a lithium ceramic via a sol-gel process to form the nickel manganese cobalt oxide particles coated with the lithium ceramic.
9. The method of claim 7, wherein the lithium ceramic is Li4Ti5O 12 or LiNbO3.
10. The method of claim 7, wherein the slurry comprising uncoated nickel manganese cobalt oxide particles further comprises heliotropism ore particles to nickel manganese cobalt oxide particles in a ratio of about 10:
90.
11. A solid-state battery cell, comprising: anode; a cathode comprising an ion conducting layer and an adjacent electronic conducting layer, the adjacent electronic conducting layer having a different material composition than the ion conducting layer; as well as A solid electrolyte is between and in direct contact with the anode and the ion conductive layer such that the ion conductive layer is between the solid electrolyte and the electronic conductive layer.
12. The solid-state battery cell of claim 11, wherein the electronically conductive layer comprises heliotropy particles and uncoated nickel manganese cobalt oxide particles.
13. The solid-state battery cell of claim 11, wherein the ion-conducting layer comprises nickel manganese cobalt oxide particles coated with lithium ceramic.
14. The solid-state battery cell of claim 13, wherein the ion-conducting layer comprises a homogeneous mixture of heliotrope particles and the nickel manganese cobalt oxide particles coated with lithium ceramic.
15. The solid-state battery cell of claim 13, wherein the nickel manganese cobalt oxide particles coated with lithium ceramic are coated with Li4Ti5O 12 or LiNbO3.