DRY-COATED ELECTRODES

Abstract

A lithium-ion battery electrode and a method for its manufacture are provided. The electrode comprises a current collector and a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder that mechanically adheres to the current collector, thereby resisting solid electrolyte interphase formation on a surface of the electrode during battery cycling.

Description

FIELD OF TECHNOLOGY

[0001] This disclosure relates to an anode composition for lithium-ion battery cells. BACKGROUND

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and renewable energy storage systems due to their high energy density and long cycle life. The performance of these batteries can depend on the characteristics of their electrodes.

[0003] The application of lithium-ion battery technology in electric vehicles and energy storage systems is increasing. Graphite remains the predominant choice for anode material in lithium-ion cells. SUMMARY

[0004] A battery comprises an electrode with a current collector and a solvent-free electrode agglomeration comprising an organolithium compound, an active material powder, and a binder. The solvent-free electrode agglomeration is mechanically bonded to the binder. The electrode is resistant to solid electrolyte interphase formation on a surface of the electrode during cycling of the battery. The organolithium compound in the electrode may include dilithium terephthalate, or dilithium 2-aminoterephthalate. Additionally, the active material powder in the electrode may be silicon-based, while the binder may be selected from a range of materials including polymer-based, rubber-based, and inorganic binders.

[0005] One method for forming an electrode involves mixing an organolithium compound with an active material powder and a binder to form a solvent-free electrode agglomeration, and applying the agglomeration to a current collector so that it mechanically adheres, thereby forming an electrode resistant to solid electrolyte interphase formation during battery cycling. The organolithium compound in this method may be selected from dilithium terephthalate, or dilithium 2-aminoterephthalate. The application process may involve calendering, and the active material powder is typically silicon-based. The method may further include steps of cutting and shaping the electrode. Another method involves coating a current collector with the solvent-free electrode agglomeration comprising an organolithium compound, an active material powder, and a binder.This creates an electrode that is resistant to solid electrolyte interphase formation during cycling. The organolithium compound can be dilithium terephthalate, or dilithium 2-aminoterephthalate. The process can also include calendering in the coating process. The active material powder used can be silicon-based. The process can further include cutting and shaping the electrode. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a battery cell according to an embodiment; and Fig. 2 is a flow diagram of an assembly process according to one embodiment. DETAILED DESCRIPTION

[0006] Embodiments are described herein. It should be understood, however, that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or reduced to show details of specific components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art.

[0007] Various features illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments not explicitly illustrated or described. The illustrated combinations of features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desired for particular applications or implementations.

[0008] Developments have been made toward high-energy-density alloy anode materials, such as silicon and silicon monoxide (SiOx), and these materials are attracting increased interest in lithium-ion battery development. Despite their potential, these anode materials, which include graphite, silicon, and silicon monoxide, present a common challenge during battery operation. During the initial cycling, the electrolyte decomposes to form a solid electrolyte interphase (SEI) film on the anode surface. This SEI film formation stabilizes the electrolyte interface and prevents further decomposition; it can also lead to irreversible charge loss and a reduction in available lithium within the battery system. This is particularly pronounced in systems employing these newer anode materials.

[0009] Another aspect of lithium-ion battery production that impacts overall efficiency is the electrode coating process. Traditionally, wet coating techniques are used in electrode manufacturing. However, this process is energy-intensive. The wet coating process requires additional energy for drying and curing, which not only increases the energy footprint of the manufacturing process but also presents challenges when scaling up production.

[0010] A typical wet coating process may begin with the preparation of a slurry, a mixture containing active materials, binders, conductive additives, and solvents. The choice of active materials can significantly impact overall performance. Binders are used to maintain structural integrity, while conductive additives enhance electrical conductivity within the electrode. Two common wet coating techniques are doctor blade coating and slurry casting. In doctor blade coating, the slurry is spread onto a current collector using a blade, resulting in a controlled, uniform layer. Slurry casting involves pouring the slurry onto the current collector and using a blade or rod to achieve the desired thickness.These processes can provide flexibility in adjusting coating parameters, allowing for customization based on specific battery requirements.

[0011] After coating, the wet film undergoes a drying and curing phase. This step removes solvents and bonds the components together, forming a stable electrode structure.

[0012] A drying process may involve allowing the solvent to evaporate, leaving the solid components on the current collector. This evaporation step can be energy-intensive and contributes to overall production time. The choice of solvent plays a role; some solvents are more volatile than others, affecting the drying rate and energy requirements.

[0013] Controlling drying conditions can be a factor in electrode formation. Uneven drying can lead to cracks, uneven thickness, or poor adhesion, potentially compromising the structural integrity and electrochemical performance of the electrode. Achieving uniformity can be challenging in certain large-scale production runs, where maintaining consistent drying conditions becomes more complex.

[0014] This disclosure relates to the development of electrodes for lithium-ion batteries using solvent-free processes, particularly the direct incorporation of organolithium compounds into the electrode fabrication process. By utilizing compounds such as dilithium terephthalate or dilithium 2-aminoterephthalate together with active material powder and a binder, this approach inherently creates a dry coating process due to the absence of solvents in the electrode mixture. The absence of solvents reduces the energy required for drying processes. The organolithium compounds prevent the formation of a solid electrolyte interphase (SEI) during battery cycling. The organolithium compounds stabilize the electrode-electrolyte interface, thereby suppressing typical decomposition reactions that lead to SEI formation.The application of organolithium compounds in the anode electrode coating process minimizes irreversible losses typically observed during battery operation. These losses often occur due to reactions at the electrode-electrolyte interface and can be mitigated by the properties of the selected organolithium compounds. The electrode manufacturing process involves a direct mixing and coating technique in which the organolithium compounds, the active material powder, and the binder are combined into a homogeneous mixture. This mixture is then applied in a dry state to the electrode surface.

[0015] Now Fig. 1, which illustrates a schematic view of a battery cell 10 having an electrode 12 and a current collector 14. The electrode 12 includes a solvent-free electrode agglomeration 16. This solvent-free electrode agglomeration 16 includes the organolithium compound 18, the active material powder 20, and the binder 22. The solvent-free electrode agglomeration 16 mechanically adheres to the current collector 14 such that the electrode 12 is resistant to SEI formation on the surface of the electrode 14 during cycling of the battery 10. The organolithium compound 18 may be dilithium terephthalate, or dilithium 2-aminoterephthalate. The organolithium compound 18 eliminates the need for additional solvents in the electrode composition.The organolithium compound 18 prevents the formation of SEI at the electrode 12 during cycling due to the chemical and electrochemical stability of the organolithium compound 18. The active material powder 20 can be silicon-based, such as silicon or silicon monoxide (SiOx). The binder 22 can be polymer-based, rubber-based, or an inorganic binder.

[0016] Fig.Figure 2 is a flowchart illustration of an assembly process according to one embodiment. In block one 24, an organolithium compound is mixed with an active material powder and a binder to form a solvent-free electrode agglomeration. In block two 26, the solvent-free electrode agglomeration is applied to a current collector such that the solvent-free electrode agglomeration mechanically adheres to the current collector to form an electrode resistant to SEI formation on a surface of the electrode during cycling. The organolithium compound used may be selected from a group of compounds such as dilithium terephthalate, or dilithium 2-aminoterephthalate.In some configurations, block two 26 may also include calendering, which involves pressing the solvent-free electrode agglomeration onto the current collector to achieve a certain desired thickness and density. The active material powder may be silicon-based, such as silicon or silicon monoxide (SiOx). Other configurations may include an optional processing step in block three 28. The processing in block three 28 may include cutting and shaping the electrode for dimensional conformity.

[0017] However, in another configuration, block one 24 may not be necessary and the process may only involve block two 26. In this configuration, block two 26 represents the step of coating a current collector with a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder to form an electrode resistant to SEI formation on a surface of the electrode. The organolithium compound may also be selected from a group comprising dilithium, terephthalate, or dilithium 2-aminoterephthalate. The coating step of block two 26 may also include calendering. The active material powder may similarly be silicon-based, such as silicon or silicon monoxide (SiOx). Optional further processing may continue in block three 28. This may include cutting and shaping the electrode for dimensional conformation.

[0018] The algorithms, methods, or processes disclosed or suggested in this specification may be implementable by or implemented by a computer, controller, or processing device, which may include any dedicated electronic control unit or programmable electronic control unit. Likewise, the algorithms, methods, or processes may be stored in many forms as computer- or controller-executable data and instructions, including, but not limited to, information permanently stored on non-writable storage media, such as read-only memory devices, and information modifiably stored on writable media, such as compact discs, random access memory devices, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented in software-executable objects.Alternatively, the algorithms, methods, or processes may be implemented in whole or in part using suitable hardware components, such as application-specific integrated circuits, field-programmable gate arrays, state machines, or other hardware components or devices, or a combination of firmware, hardware, and software components.

[0019] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms covered by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosed subject matter.

[0020] As previously described, the features of various embodiments may be combined to form further embodiments of the disclosure that may not be explicitly described or illustrated. While various embodiments may have been described as providing advantages or being preferred over other prior art embodiments or implementations with respect to one or more desired characteristics, one of ordinary skill in the art will understand that one or more features or characteristics may be compromised to achieve desired overall system attributes depending on the specific application and implementation. These attributes may include, but are not limited to, strength, durability, market capacity, 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 not outside the scope of the disclosure and may be desirable for certain applications.

[0021] A battery comprising: an electrode including a current collector and a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder mechanically adhered thereto such that the electrode is resistant to solid electrolyte interphase formation on a surface thereof during cycling of the battery.

[0022] The battery of claim 1, wherein the organolithium compound is dilithium.

[0023] The battery of claim 1, wherein the organolithium compound is terephalate.

[0024] The battery of claim 1, wherein the organolithium compound is dilithium 2-aminoterephthalate.

[0025] The battery according to claim 1, wherein the active material powder is silicon-based.

[0026] The battery of claim 1, wherein the binder is selected from a group comprising polymer-based, rubber-based or inorganic binders.

[0027] A method comprising: mixing an organolithium compound with an active material powder and a binder to form a solvent-free electrode agglomeration; and applying the solvent-free agglomeration to a current collector such that the solvent-free electrode agglomeration mechanically adheres to the current collector to form an electrode resistant to solid electrolyte interphase formation on a surface thereof during cycling. The method of claim 7, wherein the organolithium compound is selected from a group comprising dilithium terephthalate, or dilithium 2-aminoterephthalate.

[0028] The method of claim 7, wherein the applying includes calendering.

[0029] The method of claim 7, wherein the active material powder is silicon-based.

[0030] The method of claim 7, further comprising cutting and forming the electrode.

[0031] A method comprising: coating a current collector with a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder to form an electrode resistant to solid electrolyte formation on a surface thereof during cycling.

[0032] The method of claim 12, wherein the organolithium compound is selected from a group comprising dilithium, terephthalate or dilithium 2-aminoterephthalate.

[0033] The method of claim 12, wherein said coating includes calendering.

[0034] The method of claim 12, wherein the active material powder is silicon-based.

[0035] The method of claim 12, further comprising cutting the electrode.

[0036] The method of claim 12, further comprising forming the electrode.

Claims

[1] Battery comprising: an electrode including a current collector and a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder mechanically adhered thereto, such that the electrode is resistant to solid electrolyte interphase formation on a surface thereof during cycling of the battery. [2] The battery of claim 1, wherein the organolithium compound is dilithium. [3] The battery of claim 1, wherein the organolithium compound is terephalate. [4] A battery according to claim 1, wherein the organolithium compound is dilithium 2-aminoterephthalate. [5] The battery according to claim 1, wherein the active material powder is silicon-based. [6] The battery of claim 1, wherein the binder is selected from a group comprising polymer-based, rubber-based or inorganic binders. [7] Procedure comprising: Mixing an organolithium compound with an active material powder and a binder to form a solvent-free electrode agglomeration; and Applying the solvent-free electrode agglomeration to a current collector such that the solvent-free electrode agglomeration mechanically adheres to the current collector to form an electrode resistant to solid electrolyte interphase formation on a surface thereof during cycling. [8] The method of claim 7, wherein the organolithium compound is selected from a group comprising dilithium, terephthalate or dilithium 2-aminoterephthalate. [9] The method of claim 7, wherein the applying includes calendering. [10] The method according to claim 7, wherein the active material powder is silicon-based. [11] The method of claim 7, further comprising cutting and shaping the electrode. [12] Procedure comprising: Coating a current collector with a solvent-free electrode agglomeration of an organolithium compound, an active material powder, and a binder to form an electrode resistant to solid electrolyte formation on a surface thereof during cycling. [13] The method of claim 12, wherein the organolithium compound is selected from a group comprising dilithium, terephthalate or dilithium 2-aminoterephthalate. [14] The method of claim 12, wherein said coating includes calendering. [15] The method of claim 12, further comprising cutting and shaping the electrode.

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