Lithium ion battery additive

Abstract

The present disclosure provides "lithium-ion battery additives". A lithium-ion battery cell is presented. The lithium-ion battery cell includes a current collector and an active material layered on the current collector. The active material layer includes an electrode active material, a conductive agent, and a binder, and has a bottom adjacent to the current collector that includes a solid electrolyte. The battery cell further includes a liquid electrolyte that permeates the active material layer, thereby increasing ion transport during cycling through interaction with the solid electrolyte.

Description

Technical Field

[0001] This disclosure relates to electrode additive materials for use in lithium-ion batteries. Background Technology

[0002] Microscopic observation of the cross-section of a lithium-ion battery anode reveals that lithiation during charging and discharging can vary along the depth of the electrode. The lower layers of the anode can retain less lithiation, while the top layers can have a higher degree of lithiation. This variation in lithiation behavior may lead to differences in local potential within the anode. Summary of the Invention

[0003] An electrode includes: a current collector; an active material layered on the current collector, the active material comprising an electrode active material, a conductive agent, and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and a liquid electrolyte permeating the active material layer and configured to increase ion transport with the solid electrolyte during cycling of the electrode. The current collector may be copper-based. The solid electrolyte may be a sulfide-based material. The solid electrolyte may be an oxide-based material. The solid electrolyte may be a halide-based material. The solid electrolyte may be less than 10% by weight of the electrode. The liquid electrolyte may be a carbonate-based electrolyte. The active material may be graphite-based.

[0004] A method of manufacturing an electrode includes: depositing an underlayer of electrode active material, a conductive agent, a binder, and a solid electrolyte onto a current collector; depositing a top layer of electrode active material, a conductive agent, and a binder onto the underlayer; and permeating the layer with a liquid electrolyte to promote ion transport with the solid electrolyte during cycling of the electrode. The solid electrolyte may be a sulfide, oxide, or halide. A spraying technique may be used to deposit the top layer. The deposited layer may be dried before permeation with the liquid electrolyte. The liquid electrolyte may be a mixture of ethylene carbonate and diethyl carbonate. The layer may be pressed after deposition. The electrolyte may include less than 10% by weight of a solid electrolyte.

[0005] A lithium-ion battery cell includes: a positive electrode assembly; a negative electrode assembly layered on a current collector, the negative electrode assembly comprising an electrode active material, a conductive agent, and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and a liquid electrolyte permeating both electrode assemblies. The solid electrolyte is configured to increase the local lithium-ion presence in the negative electrode assembly during continuous cycling of the lithium-ion battery cell. The solid electrolyte in the bottom layer of the negative electrode assembly may be less than 10% by weight of the lithium-ion battery cell. The solid electrolyte in the bottom layer of the negative electrode assembly may be an oxide. The solid electrolyte in the bottom layer of the negative electrode assembly may be a halide-based material. Attached Figure Description

[0006] Figure 1 It is an optical microscope image of the cross-section of the anode of a lithium-ion battery;

[0007] Figure 2 This is a schematic diagram of a lithium-ion battery cell; and

[0008] Figure 3 This is a flowchart of a method for manufacturing lithium-ion battery electrodes. Detailed Implementation

[0009] This document describes detailed embodiments of the invention to provide a thorough understanding of its implementation and functionality. However, these embodiments are presented by way of example and are not intended to limit the invention, which can encompass various alternative configurations and materials. For example, as described herein, the use of solid electrolyte particles in a layer below the negative electrode active material layer adjacent to the current collector may involve variations in the type of solid electrolyte material (such as sulfides, oxides, halides, or polymers) and their specific integration methods. The accompanying drawings included in this disclosure are schematic representations and are not necessarily drawn to scale; features may be exaggerated or minimized to emphasize details of particular components. Specific structural and functional details disclosed herein, such as the incorporation of less than 10% by weight of solid electrolyte particles or the use of a liquid electrolyte permeating both electrode assemblies, should not be construed as limiting, but rather as a representative basis for teaching those skilled in the art how to implement and adapt the invention in various ways.

[0010] Unless otherwise expressly stated, all numerical values ​​and ranges provided in this disclosure, such as those relating to quantities, measurements, percentages, weights, and other numerical references, should be interpreted as approximations. This applies even where the term "about" is not explicitly used. For example, if an underlying material is described as containing "less than 10% by weight of solid electrolyte," this covers slight variations due to material properties, manufacturing tolerances, or intended functionality. Similarly, when ranges such as "100 to 200 units" are described, they should be interpreted as "about 100 to about 200 units," thus taking into account practical variability. These principles apply to disclosed values ​​such as the weight percentage of solid electrolyte, the ratio of active material, and the enhancement of ionic conductivity achieved through the use of a liquid electrolyte interacting with solid electrolyte particles. These inherent variations are considered within the scope of the invention because they are adapted to the actual manufacturing processes and material behavior described herein.

[0011] For lithium-ion batteries in electric vehicles, the ability to quickly recharge is a factor in consumer acceptance. High-energy-density batteries, typically designed with thick anode electrodes to maximize energy storage, may face challenges during fast charging. During charge and discharge cycles, lithium ions (Li...) within the anode... + The lithium distribution may become uneven, leading to incomplete lithiation of the lower layers while the upper layers achieve complete lithiation. This imbalance can create localized regions of high overpotential in the top layer of the anode, especially during high-current fast charging. Under certain conditions, these overpotentials may drop below the lithium plating threshold, triggering lithium deposition on the electrode surface.

[0012] Semi-solid-state batteries incorporating a high proportion of solid-state electrolytes (SSEs) within electrode active material layers have been developed. These layers include electrode active materials, conductive agents, binders, and composite electrolytes, which may comprise oxide SSEs, polymer electrolytes formed via in-situ polymerization, and / or liquid electrolytes. Polymers and liquid electrolytes increase the contact between the active material and the SSE, thereby reducing impedance and enhancing the electrochemical properties of the electrode.

[0013] Despite these advantages, semi-solid-state batteries face limitations, particularly in terms of energy density. Solid electrolytes are relatively dense materials, and their high proportion within the electrodes, compared to conventional lithium-ion batteries, reduces the overall energy density. Furthermore, the use of polymers and solid electrolytes can introduce complexities related to contact resistance and the need for precise manufacturing conditions.

[0014] This disclosure increases lithiation uniformity within the anode by integrating a small amount (< 10 wt%) of solid electrolyte additives relative to the entire battery cell into the lower layer of the anode electrode adjacent to the current collector. This configuration maintains stable ion transport and prevents localized overpotential conditions. These additives (which may include sulfides, oxides, polymers, or halides) increase localized Lithium concentration in regions prone to ion depletion under high-current charging. + The presence of ions. This localized expansion of ion availability alleviates the Li + The gradient effect reduces the likelihood of lithium plating and dendrite formation caused by overpotential.

[0015] Each category of solid electrolyte additives offers different advantages. For example, sulfides exhibit high ionic conductivity and flexibility, thus supporting efficient ion transport at the interface between the additive and the anode material. Examples of sulfides include lithium thiophosphate, such as Li... 10 GeP2S 12 And related materials. Oxide-based solid electrolytes (such as lithium garnet or perovskite oxides) possess high chemical stability and heat resistance, making them suitable for long-term operation under harsh conditions. Polymer-based additives (including polyethylene oxide or cross-linked polymer matrices) increase electrode flexibility while maintaining compatibility with liquid electrolytes, thereby effectively reducing interfacial impedance. Compared to other solid electrolytes, halide solid electrolytes (such as lithium chloride or lithium bromide) offer lower densities and facilitate integration with conventional liquid electrolytes while maintaining ionic conductivity. By adjusting the composition and proportion of these additives, the resulting configuration can maintain uniform lithiation throughout the anode.

[0016] Unlike semi-solid-state batteries, the proposed electrode configuration does not rely on polymer electrolytes or a high proportion of solid electrolytes. By maintaining the liquid electrolyte content at levels similar to conventional lithium-ion batteries, the proposed configuration prevents the high contact resistance issues associated with solid-state interfaces. This maintains consistent electrochemical performance of the battery.

[0017] Furthermore, the low proportion of solid electrolyte additives maintains an energy density comparable to conventional lithium-ion batteries. This contrasts with semi-solid designs where the high density of solid electrolyte materials can negatively impact energy density.

[0018] Figure 1 This is an optical microscopic cross-section of a lithium-ion battery anode during charge and discharge cycles. The cross-section shows differences in lithiation depth at the anode. Specifically, the lower layer of the anode adjacent to the current collector is significantly underlithilated or remains completely unlithilated. In contrast, the upper layer of the anode closer to the separator is fully lithilated. This uneven lithiation distribution is evident from the visible differences in material structure and color associated with the degree of lithiation.

[0019] The lithiation imbalance between the lower and upper layers of the anode can pose electrochemical challenges. Due to the non-uniform ion distribution, the highly lithiated top layer of the anode may experience locally high overpotentials. Under certain conditions, these overpotentials may drop below the lithium plating potential, initiating lithium plating on the electrode surface. Prolonged lithium plating increases the likelihood of dendrite formation.

[0020] Figure 2 This is a schematic diagram of a lithium-ion battery cell 10. The lithium-ion battery cell 10 includes a positive electrode assembly 12, a separator 14, and a negative electrode assembly 16. The positive electrode assembly 12 includes a current collector 18 and a positive electrode active material layer 20. The current collector 18 can be a conductive metal, such as aluminum, chosen due to its lightweight properties, high conductivity, and compatibility with the positive electrode active material layer 20. The positive electrode active material layer 20 can include active materials, such as lithium nickel cobalt manganese oxide, lithium iron phosphate, or lithium cobalt oxide. The positive electrode active material layer 20 may also contain conductive agents, such as carbon black and polymer binders, to maintain mechanical integrity and electrical connectivity.

[0021] The separator 14 is a thin, porous, and electrically insulating membrane positioned between the positive electrode assembly 12 and the negative electrode assembly 16 to prevent direct contact between them while allowing Li + Transportation. The partition 14 can be made of polyethylene or polypropylene, and may also include a ceramic coating to increase thermal stability and electrolyte wettability.

[0022] The negative electrode assembly 16 includes a negative electrode active material layer 22 and a negative current collector 24. The negative current collector 24 may be made of copper, which provides conductivity and compatibility with the negative electrode active material layer 22. The negative electrode active material layer 22 includes a mixture of negative electrode active material particles 26 and solid electrolyte particles 28, the mixture being primarily present in the lower layer of the negative electrode active material layer 22 near the negative current collector 24. Guiding the solid electrolyte particles 28 to the vicinity of the lower layer mitigates lithiation imbalance by increasing the Li+ concentration closer to the current collector 24. The negative electrode active material particles 26 may include graphite, lithium titanate, or silicon-based composites. These materials serve as Li+ during charge and discharge cycles. + The main components for insertion and de-insertion. The positive electrode active material assembly 12 and the negative electrode active material assembly 16 may contain binder materials to increase the mechanical stability and adhesion between layers and between current collectors 14.

[0023] Solid electrolyte particles 28 are partially integrated near the bottom of the negative electrode active material layer 22, constituting less than 10% by weight of the lithium-ion battery cell 10. The solid electrolyte particles 28 increase the local Li-ion content. + The presence and ionic conductivity, especially in the presence of Li +In the depleted region. Solid electrolyte particles 28 may include sulfides (such as Li₂). 10 GeP2S 12 Or Li6PS5Cl), oxides (such as Li7La3Zr2O) 12 Or perovskite oxides), polymers (such as polyethylene oxide or polyacrylonitrile-based composites) or halides (such as lithium chloride or lithium bromide).

[0024] The lithium-ion battery cell 10 may further include a liquid electrolyte 30 permeating both the positive electrode assembly 12 and the negative electrode assembly 16. The liquid electrolyte 30 facilitates ion transport between the electrode assemblies via a separator 14 and interacts with solid electrolyte particles 28 in the negative electrode active material layer 22 to increase the local lithium-ion concentration during cycling. The liquid electrolyte 30 may be a carbonate-based solvent (such as ethylene carbonate and diethyl carbonate) mixed with a lithium salt (such as lithium hexafluorophosphate).

[0025] Figure 3 This is a flowchart of method 32 for manufacturing a lithium-ion battery electrode. Step 34 begins by depositing an underlayer comprising electrode active material, a conductive agent, a binder, and a solid electrolyte onto a current collector. In step 36, a top layer of electrode active material, conductive agent, and binder is then deposited onto the current collector and the underlayer. Step 36 may utilize a spraying technique to achieve uniformity and integration with the underlying layer. In step 38, once the layers have been deposited, they are permeated with a liquid electrolyte to promote ion transport and interaction with the solid electrolyte. Prior to step 38, the layers may be dried to remove residual solvent, thereby ensuring effective electrolyte permeation. The layers may be further subjected to pressing after deposition to increase mechanical stability and material-to-material contact.

[0026] While the foregoing description provides exemplary embodiments of the invention, it is not intended to cover all possible variations or configurations. The terminology used herein is descriptive and not limiting. It should be understood that modifications and adaptations, such as variations in the type or proportion of the solid electrolyte, electrode structure, or manufacturing technique, can be made without departing from the spirit and scope of the invention. Furthermore, individual features described in different embodiments can be combined or reconfigured to create additional implementations consistent with the principles disclosed herein.

[0027] According to the present invention, an electrode is provided having: a current collector; an active material layered on the current collector, the active material comprising an electrode active material, a conductive agent and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and a liquid electrolyte permeating the active material and configured to promote ion transport with the solid electrolyte during cycling of the electrode.

[0028] According to an embodiment, the current collector is copper-based.

[0029] According to an embodiment, the solid electrolyte is a sulfide-based material.

[0030] According to an embodiment, the solid electrolyte is an oxide-based material.

[0031] According to an embodiment, the solid electrolyte is a halide-based material.

[0032] According to an embodiment, the solid electrolyte is less than 10% by weight of the electrode.

[0033] According to an embodiment, the liquid electrolyte is a carbonate-based electrolyte.

[0034] According to an embodiment, the active material is graphite-based.

[0035] According to the present invention, a method for manufacturing an electrode includes: depositing an underlayer of electrode active material, conductive agent, binder and solid electrolyte onto a current collector; depositing a top layer of electrode active material, conductive agent and binder onto the underlayer; and permeating the layer with a liquid electrolyte.

[0036] According to an embodiment, the solid electrolyte includes sulfides, oxides, or halides.

[0037] According to an embodiment, a spraying technique is used to deposit the top layer.

[0038] According to an embodiment, the invention is further characterized by drying the deposited layer prior to the permeation.

[0039] According to an embodiment, the liquid electrolyte is a mixture of ethylene carbonate and diethyl carbonate.

[0040] According to an embodiment, the invention is further characterized by pressing the layer after deposition.

[0041] According to an embodiment, the electrolyte comprises less than 10% by weight of a solid electrolyte.

[0042] According to the present invention, a lithium-ion battery cell is provided, comprising: a positive electrode assembly; a negative electrode assembly layered on a current collector, the negative electrode assembly comprising an electrode active material, a conductive agent and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and a liquid electrolyte permeating both of the electrode assemblies and configured to increase the local lithium-ion presence of the solid electrolyte in the negative electrode assembly during continuous cycling of the lithium-ion battery cell.

[0043] According to an embodiment, the solid electrolyte at the bottom of the negative electrode assembly is less than 10% of the weight of the lithium-ion battery cell.

[0044] According to an embodiment, the solid electrolyte in the bottom of the negative electrode assembly is an oxide-based material.

[0045] According to an embodiment, the solid electrolyte at the bottom of the negative electrode assembly is a halide-based material.

Claims

1. An electrode comprising: Current collector; An active material, layered on the current collector, comprising an electrode active material, a conductive agent, and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and A liquid electrolyte, which permeates the active material and is configured to promote ion transport with the solid electrolyte during cycling of the electrode.

2. The electrode of claim 1, wherein the current collector is copper-based.

3. The electrode of claim 1, wherein the solid electrolyte is a sulfide-based material.

4. The electrode of claim 1, wherein the solid electrolyte is an oxide-based material.

5. The electrode of claim 1, wherein the solid electrolyte is a halide-based material.

6. The electrode of claim 1, wherein the solid electrolyte is less than 10% by weight of the electrode.

7. The electrode of claim 1, wherein the liquid electrolyte is a carbonate-based electrolyte.

8. The electrode of claim 1, wherein the active material is graphite-based.

9. The electrode of claim 1, wherein the binder is polyvinylidene fluoride.

10. A method for manufacturing an electrode, comprising: The electrode active material, conductive agent, binder and solid electrolyte are deposited onto the current collector; A top layer of electrode active material, conductive agent, and binder is deposited onto the bottom layer; as well as The layer is permeated with a liquid electrolyte.

11. The method of claim 10, wherein the solid electrolyte comprises a sulfide, an oxide, or a halide.

12. A lithium-ion battery cell, comprising: Positive electrode assembly; A negative electrode assembly, layered on a current collector, comprising an electrode active material, a conductive agent, and a binder, and having a bottom adjacent to the current collector, the bottom comprising a solid electrolyte; and A liquid electrolyte permeates both electrode assemblies and is configured to increase the local lithium-ion presence of the solid electrolyte in the negative electrode assembly during continuous cycling of the lithium-ion battery cell.

13. The lithium-ion battery cell of claim 12, wherein the solid electrolyte in the bottom of the negative electrode assembly is less than 10% of the weight of the lithium-ion battery cell.

14. The lithium-ion battery cell of claim 12, wherein the solid electrolyte in the bottom of the negative electrode assembly is a sulfide-based material.

15. The lithium-ion battery cell of claim 12, wherein the solid electrolyte in the bottom of the negative electrode assembly is a halide-based material.

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