Non-dendritic anodes and current collectors for lithium metal batteries and lithium-ion batteries

Abstract

The concepts of the present disclosure relate to lithium-ion batteries and lithium-metal batteries, including methods for preparing multi-component alloy (MCA) systems having a body-centered cubic (bcc) crystal structure as anodes and current collectors, wherein no dendrites are formed in the lithium-ion or lithium-metal batteries throughout the battery charging and discharging process. The MCA systems include the following alloy compositions: (i) 40 atomic% iron, 40 atomic% aluminum or gallium, and 20 atomic% magnesium; or (ii) 10 atomic% iron, 40 atomic% aluminum or gallium, and 50 atomic% magnesium; or (iii) 50 atomic% iron, 40 atomic% aluminum or gallium, and 10 atomic% magnesium.

Description

[Technical Field]

[0001] <Statement on the Government's Interests> This invention was made with government support under DE-EE0009649, granted by the U.S. Department of Energy (DOE). The government has certain rights in this invention.

[0002] <Cross-reference of related applications> This patent application claims priority under § 119(e) of U.S. Patent Act to U.S. Provisional Patent Application No. 63 / 533,998, titled "DENDRITE-FREE ANODES AND CURRENT COLLECTORS FOR LITHIUM METAL BATTERIES AND LITHIUM-ION BATTERIES," filed with the U.S. Patent and Trademark Office on 22 August 2023, the contents of which are incorporated herein by reference in their entirety.

[0003] The concept of this disclosure relates to the identification, design, fabrication, and preparation methods for multicomponent alloy (MCA) systems having a body-centered cubic (bcc) crystal structure as anodes and current collectors for lithium metal batteries and lithium-ion batteries, which prevent the formation of lithium dendrites, which are known to adversely affect battery performance. [Background technology]

[0004] The rapid development of portable electronic devices, electric vehicles, and renewable energy systems is driving the demand for batteries with higher energy density, faster charging capabilities, and improved safety. Lithium-ion batteries (LIBs) have been at the forefront of this technological revolution for decades due to their favorable energy density, long cycle life, and reliability. However, as the demand for more powerful and longer-lasting energy storage devices increases, the limitations of conventional LIBs are becoming increasingly apparent. Specifically, the energy density of LIBs is approaching its theoretical maximum, prompting researchers to explore alternative battery chemical compositions and structures. Lithium metal batteries (LMBs) have recently attracted considerable attention as a promising successor to LIBs, mainly due to the superior theoretical capacity of lithium metal (3,860 mAh / g) and its low electrochemical potential (-3.04 V relative to a standard hydrogen electrode). The large theoretical specific capacity of Li metal, and primarily the ability to potentially utilize it, are the main reasons for the recent interest. Metallic lithium has always been at the center of interest since the concept of rechargeable Li-ion batteries became widespread in the mid-1970s. However, the extremely high reactivity of metallic lithium to the atmosphere, as well as the dangerous flammability and explosiveness of its exothermic oxidation reaction with air and moisture, seriously hindered the use of metallic lithium. The advent of the concept of intercalation, and the resulting ionized lithium Li +The ability to store lithium in carbon and graphite layers presented a good and superior alternative to the use of metallic lithium, completely avoiding the risks of fire and explosion associated with metallic lithium. However, carbon and graphite anodes can only store one Li for every six carbon atoms, limiting the theoretical specific capacity to 372 mAh / g, which is one-tenth the capacity offered by metallic lithium. Therefore, renewed interest in lithium necessitates seeking means to protect metallic lithium during electrode fabrication, thereby preventing contact with air and moisture and thus avoiding the possibility of fire and explosion. With a higher theoretical specific capacity, the use of lithium metal as an anode material has the potential to revolutionize energy storage by significantly increasing energy density, thereby extending the range of electric vehicles and the lifespan of portable devices. Despite these advantages, the practical implementation of lithium metal anodes is fraught with difficulties, the most significant of which is the formation of harmful lithium dendrites.

[0005] Dendrites are needle-like or moss-like lithium structures that appear on the surface of lithium metal anodes due to heterogeneous nucleation and growth of Li during repeated charge and discharge cycles. This results in heterogeneous deposition of lithium, leading to the generation and propagation of these needle-like structures that emerge from the electrode surface like tree branches. The formation and heterogeneous deposition of dendrites of metallic Li from lithium ions can be exacerbated by factors such as high current density, local ion flux, and the inherent instability of the lithium metal-electrolyte interface. Dendrite growth not only reduces battery efficiency by consuming active lithium but also poses serious safety risks. If dendrites puncture and proliferate into the separator, they can cause internal short circuits, leading to thermal runaway, rapid temperature increases resulting in fire, or explosions at temperatures exceeding the flash point and flammability range of organic electrolytes. These safety concerns are a major obstacle to the commercialization of lithium metal batteries and necessitate the development of strategies to suppress dendrite formation.

[0006] In recent years, considerable research efforts have been made to address the dendrite problem and improve the performance of lithium metal anodes. Focusing on innovations in both materials and electrode design, various methods are being explored to achieve dendrite-free lithium deposition. One promising strategy involves the use of protective coatings on lithium metal anodes. These coatings, such as solid electrolyte interphase (SEI) and artificial passivation layers, act as barriers that stabilize the interface between the lithium metal and the electrolyte, thereby reducing the possibility of dendrite formation. However, the stability of these coatings during large and rapid changes in current density during operation is always questionable, which can lead to delamination of the plating and detachment of the metallic lithium, thereby, if the coating is damaged, leading to dendrite formation.

[0007] Another approach involves developing three-dimensional (3D) structured current collectors that provide a more uniform distribution of lithium ions and accommodate volume changes at the anode during the cycle. This not only improves the mechanical stability of the electrodes but also promotes lithium deposition, thereby reducing dendrite growth. However, the efficient engineering design and construction of 3D frameworks or confinement structures that eliminate dendrite formation over the entire lifespan of the battery remains a challenge. This is because most of these 3D structures involve creating porous architectures that allow Li to be deposited within pores. However, even if 3D architectures and confinements can be engineered with meticulous care to accommodate metallic Li, these 3D structures and confinement systems carry the risk of deposited Li agglomerating and filling the confinement structure and porous channels. Thereafter, when voids and channels are completely covered and filled with metallic Li, it ultimately leads to dendrite formation.

[0008] Furthermore, electrolyte engineering design is emerging as a crucial factor in preventing dendrite formation. Advanced electrolyte design, with optimized ionic conductivity, solvent composition, and additive selection, has been shown to influence lithium ion transport and deposition. For example, the incorporation of certain additives can modify the lithium metal surface and facilitate the formation of stable SEIs, which are important for suppressing dendrite growth. The ability of these additives to suppress dendrite formation throughout the entire lifespan of a Li-ion battery and the current surges experienced during Li-ion battery operation presents unique challenges for efficient and effective electrolyte design.

[0009] In addition, solid electrolytes (SSEs) have been studied for their potential to eliminate dendrites by providing a mechanically rigid medium that prevents dendrite penetration. However, while SSEs eliminate the use of organic liquid electrolytes and the potential risks of low flash points and temperatures exceeding the boiling and ignition temperatures of organic solvents, the inherent risks of heterogeneous Li deposition and Li delamination remain. This creates the possibility that dendrites may form and eventually migrate through the cell, causing a short circuit. Most SSEs are either ceramics, polymers, or polymer-ceramic composites, which tend to be mechanically brittle. Therefore, there is a risk that dendrites may penetrate the brittle, thin SSE layer, causing an undesirable short circuit that could lead to cell failure and rupture. Thus, metallic Li remains exposed to air and moisture. This exposure, combined with temperature fluctuations resulting from short circuits and increased resistance, makes it impossible to rule out the possibility of dangerous explosions and fires. Therefore, there is a need for transformative methods to address the root cause of dendrite formation in the metal electrodes themselves, which is the basis of the concepts of this disclosure.

[0010] As previously mentioned, significant advances have been made in coating, 3D electrode design, and the advent of SSE. Despite these advances, several challenges remain in fully realizing a dendrite-free Li metal anode that is practical and scalable for commercial applications, due to conventional methods of storing Li ions. Typically, as previously noted, Li ions tend to plate onto the surface of the Li metal, forming non-uniform deposits that can lead to dendrite formation, potentially compromising battery safety and performance.

[0011] Therefore, there is a need in the art to design and develop anodes, current collectors, and related methods to effectively mitigate dendrite growth in lithium metal batteries and lithium-ion batteries.

[0012] The concepts of this disclosure relate to addressing the problem of dendrite formation in the fundamental stages of metal alloy development and anode modification. The high-efficiency anodes, current collectors, and methods of the concepts of this disclosure are effective for reversibly storing and cycling dendrite-free lithium, which can provide high-power and high-energy-density lithium anodes and lithium-ion-based batteries. [Overview of the project]

[0013] In one embodiment, the concept of the present disclosure includes a lithium-ion battery or lithium-metal battery, comprising an anode-free current collector, which is a multi-component alloy comprising 40 atomic% iron, 40 atomic% aluminum or gallium and 20 atomic% magnesium, or 10 atomic% iron, 40 atomic% aluminum or gallium and 50 atomic% magnesium, or 50 atomic% iron, 40 atomic% aluminum or gallium and 10 atomic% magnesium, a lithium-containing cathode, and an electrolyte, wherein no dendrites are formed throughout the entire charging and discharging process of the battery.

[0014] The electrolyte may comprise a polymer gel.

[0015] The cathode may be selected from the group consisting of LiCoO₂, LiNiO₂, LiNi 0.8 Co 0.1 Mn 0.1 O₂, LiNi 1-x Co x O₂ (0<x<1), and LiNi 1-x-y Mn x Co y O₂ (0<x+y<1).

[0016] The multi-component alloy may comprise a body-centered cubic crystal structure that is maintained throughout the charging and discharging processes of the battery.

[0017] The multi-component alloy may exhibit optimal interfacial energy for alloying with lithium.

[0018] In another aspect, the concept of the present disclosure includes a lithium-ion battery or a lithium metal battery, comprising: a Li-containing anode comprising a multi-component alloy in solid solution form, the multi-component alloy comprising 40 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 20 atomic percent of magnesium; or 10 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 50 atomic percent of magnesium; or 50 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 10 atomic percent of magnesium; a cathode; and an electrolyte, wherein dendrites are not formed throughout the charging and discharging processes of the battery.

[0019] In another embodiment, the concept of the present disclosure includes a method for preparing an anode-free current collector, comprising preparing a multi-component alloy, which includes: obtaining iron, aluminum or gallium and magnesium in dry form; blending or mixing the dry forms of iron, aluminum or gallium and magnesium based on an alloy composition selected from, hereafter, 40 atomic% iron, 40 atomic% aluminum or gallium and 20 atomic% magnesium, or 10 atomic% iron, 40 atomic% aluminum or gallium and 50 atomic% magnesium, or 50 atomic% iron, 40 atomic% aluminum or gallium and 10 atomic% magnesium; subjecting the alloy composition to a high-energy grinding treatment to form a high-energy grinding composition; and forming a current collector comprising the high-energy grinding composition, wherein no dendrites are formed in a lithium-ion battery or lithium-metal battery throughout the battery charging and discharging process.

[0020] The method may further include forming pellets containing a high-energy pulverized composition before forming a current collector. In certain embodiments, pellet formation may include cold pressing, cold isotropic pressing, and cold uniaxial pressing at a moderate temperature of about 100-150°C. Furthermore, in certain embodiments, the method may include cold rolling the pellets to form foil for direct use as a current collector.

[0021] In yet another embodiment, the concept of the present disclosure includes a method for preparing a Li-containing anode, comprising preparing a multicomponent alloy, which includes: obtaining iron, aluminum or gallium and magnesium in dry form; blending or mixing the dry forms of iron, aluminum or gallium and magnesium based on an alloy composition selected from, hereafter, 40 atomic% iron, 40 atomic% aluminum or gallium and 20 atomic% magnesium, or 10 atomic% iron, 40 atomic% aluminum or gallium and 50 atomic% magnesium, or 50 atomic% iron, 40 atomic% aluminum or gallium and 10 atomic% magnesium; subjecting the alloy composition to a high-energy grinding treatment to form a high-energy grinding composition; and coating or depositing the high-energy grinding composition onto a current collector to form a solid solution, wherein no dendrites are formed in a lithium-ion battery or lithium metal battery throughout the battery charging and discharging process.

[0022] This method may further include forming pellets containing a high-energy pulverization composition, forming a slurry containing the pellets, and applying the slurry to a current collector to form a solid solution.

[0023] In this method, the dried form may be a powder.

[0024] In this method, the ratio of powder to mill ball may remain constant at 1:1.

[0025] In this method, the solid solution may contain a body-centered cubic crystal structure.

[0026] In this method, forming a slurry may involve adding polyvinylidene fluoride as a binder. [Brief explanation of the drawing]

[0027] [Figure 1]In situ XRD measurements of high-purity PPFAM442 pellets treated at 0.25 mA / cm2 for 15 hours, the formation of metallic Li and associated Li phases is not shown in relation to Li ion insertion into the alloy according to certain embodiments of the concepts of this disclosure.

[0028] [Figure 2] This disclosure presents an electrochemical evaluation of a slurry-coated FAM145 electrode for Li storage over 31 cycles at various charging speeds ranging from 1 mAh to 20 mAh, according to a specific embodiment of the concept of this disclosure.

[0029] [Figure 3a] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, respectively, according to a specific embodiment of the concept of this disclosure, are shown: voltage profile and area capacity. [Figure 3b] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 1 mAh. [Figure 3c] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 1 mAh. [Figure 3d] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, respectively, according to a specific embodiment of the concept of this disclosure, are shown: voltage profile and area capacity. [Figure 3e] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 5 mAh. [Figure 3f] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 1 mAh and 5 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 5 mAh.

[0030] [Figure 4a] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12 mAh and 18 mAh, respectively, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 4b] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12mAh and 18mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 12mAh. [Figure 4c] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12mAh and 18mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 12mAh. [Figure 4d] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12 mAh and 18 mAh, respectively, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 4e] The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12mAh and 18mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 18mAh. [Figure 4f]The following electrochemical evaluations of the FAM145 electrode for Li storage over 31 cycles at charging speeds of 12mAh and 18mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 18mAh.

[0031] [Figure 5a] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, respectively, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 5b] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 1 mAh. [Figure 5c] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 1 mAh. [Figure 5d] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, respectively, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 5e] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 2 mAh. [Figure 5f] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 2 mAh. [Figure 5g]The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, respectively, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 5h] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 4 mAh. [Figure 5i] The following electrochemical evaluations of the FAM541 electrode for Li storage over 30 cycles at charging speeds of 1, 2, and 4 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 30th cycles at 4 mAh.

[0032] [Figure 6] This disclosure presents an electrochemical evaluation of a slurry-coated FAM442 electrode for Li storage at various charging speeds ranging from 1 mAh to 18 mAh, according to a specific embodiment of the concept of this disclosure.

[0033] [Figure 7a] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 7b] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 1 mAh. [Figure 7c]The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for the first and 31st cycles at 1 mAh. [Figure 7d] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 7e] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for cycles 325 and 525 at 12 mAh. [Figure 7f] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for cycles 325 and 525 at 12 mAh. [Figure 7g] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to certain embodiments of the concepts of this disclosure, are shown: voltage profile and area capacity. [Figure 7h] The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for cycles 525 and 725 at 15 mAh. [Figure 7i]The following electrochemical evaluations of the FAM442 in a coin cell configuration for Li storage over 31 and 200 cycles, respectively, at charging speeds of 1, 12, and 15 mAh, according to a specific embodiment of the concept of this disclosure, are shown: voltage profiles for cycles 525 and 725 at 15 mAh.

[0034] [Figure 8] The following electrochemical evaluations of a FAM442 electrode in a single-layer pouch cell for Li storage over 100 cycles at a charging rate of 9 mAh are shown according to a specific embodiment of the concept of this disclosure: a) voltage profile and area capacity, and b-c) voltage profiles for the first and 100th cycles at a 9 mAh charge.

[0035] [Figure 9] This disclosure presents an electrochemical evaluation of FAM442 pellets (PFAM442-G) prepared using Ga as a sintering agent as a current collector for Li storage at various charging speeds ranging from 1 mAh to 8 mAh in a coin cell configuration, according to a specific embodiment of the concept of this disclosure.

[0036] [Figure 10] The following electrochemical evaluations of PFAM442-G pellets in a coin cell configuration for Li storage over 110 cycles, each at charging speeds of 1, 4, and 8 mAh, according to certain embodiments of the concepts of this disclosure, are shown: a) voltage profile and area capacity, b-c) voltage profile for the 1st and 110th cycles at 1 mAh, d) voltage profile and area capacity, e-f) voltage profile for the 221st and 330th cycles at 4 mAh, g) voltage profile and area capacity, h-i) voltage profile for the 441st and 550th cycles at 8 mAh.

[0037] [Figure 11]The following electrochemical evaluations of high-purity untreated pellets of FAM442 (PPFAM442) in a coin cell configuration for Li storage over 250 cycles at a current density of 1 mA / cm² achieving an area capacity of 5 mAh / cm² are shown according to certain embodiments of the concepts of the present disclosure: a) voltage profile and area capacity over 250 cycles, and b-f) voltage profiles for the 1st, 109th, 152nd, 174th, and 250th cycles.

[0038] [Figure 12] The following electrochemical evaluations of pre-lithium-treated high-purity untreated pellets of FAM442 (PPFAM442) as a Li reservoir over 300 cycles at a current density of 2 mA / cm2, achieving an area capacity of 6 mAh / cm2, are shown according to certain embodiments of the concepts of this disclosure: a) sequential pre-lithium treatment of PPFAM442 up to 15 mAh / cm2 in CCCV, b) voltage profile and area capacity at 6 mAh / cm2, 300 cycles, where Li ions are cycled from PPFAM442 to the opposing Li metal, and c-e) voltage profiles for the 1st, 153rd, and 300th cycles. [Modes for carrying out the invention]

[0039] The concept of this disclosure relates to achieving complete solid solution formation without inducing any phase separation or the formation of intermetallic alloys or intermediate structures by preserving crystallographic symmetry in metallic lithium (Li), i.e., preserving a body-centered cubic (bcc) crystal structure, being identical to metallic Li, and reducing the interfacial energy to an optimal value. As a result, there is no Li deposition or plating and delamination; rather, alloy formation is observed throughout the entire charging and discharging process, completely eliminating dendrite formation resulting from Li deposition or plating on the alloy surface. The preservation of the Li lattice structure, as well as the optimal enthalpy and interfacial energy of the mixing, results in the elimination of interfacial disorder leading to a desired planar interface rather than a morphologically disordered interface that causes notorious and harmful dendrites.

[0040] Various alloys, known as multicomponent alloys (MCAs), have been identified. These are all structurally equivalent to metallic Li and maintain bcc symmetry. These alloys exhibit a high solubility limit of 62 atomic percent of metallic Li, leading to the formation of solid solution alloys. This results in a maximum area capacity of 18 mAh / cm² for Li alloying with MCA systems. 2 These materials reach a density of approximately 100 microns (Li). Furthermore, they are lightweight alloys with a density more than 50% lower than copper, the conventionally used anode current collector.

[0041] The concept of this disclosure transforms existing technologies that use copper foil as a current collector and metallic Li foil as an anode. The concept of this disclosure directly uses an MCA alloy as a Li-containing solid solution MCA anode and a Li-free MCA current collector. Solid solution formation offers the possibility of replacing the copper current collector with an MCA alloy of equivalent thickness, presenting equivalent capacity to 100 microns of Li used as an anode. Thus, a capacity of 3861 mAh / g identical to that of metallic Li can be achieved as a solid solution in these novel MCA alloys, which have a density more than 50% lower than metallic copper, resulting in a lightweight structure that shows a complete transformation in the anodes of Li-metal batteries and lithium-ion batteries without the formation of dendrites.

[0042] MCA alloys can be manufactured with or without lithium. Non-lithium-treated MCA is LiNi 1-x Co x O2(0 <x<1)、LiNi 1-x-y Mn x Co y O2(0 <x+y<1)、およびLiNi 0.8 Co 0.1 Mn 0.1These materials, including O2 (NMC-811), function as anode-free current collectors for cycling batteries with Li-containing cathodes, such as LiCoO2 in current Li-ion batteries, and are used in some commercial systems. They also function directly as Li-containing current collectors in developing systems such as Li-S, which utilizes LiNiO2 and Li2S as cathodes, or pre-lithium-treated alloys, even in cycle batteries with lithium-free cathodes, such as sulfur in Li-S batteries and in Li-air batteries.

[0043] Therefore, the MCA system replaces the use of copper as a current collector and the use of separate Li metal foil, thereby resulting in a significant weight reduction that leads to a higher energy density.

[0044] The design of an MCA system with a bcc crystal structure is similar to metallic Li, where Li can dissolve into the solid lattice to form a solid solution rather than being plated onto the surface. The concept of this disclosure involves identifying such an MCA system having a bcc crystal structure with optimal interfacial energy and mixed enthalpy for Li to dissolve within its structure and form a solid solution. This prevents non-uniform deposition and subsequent dendrite growth. The concept eliminates the possibility of Li plating on the surface because Li ions dissolve into the alloy during discharge and are subsequently ionized during charging, leaving a solid solution alloy that leaves a Li-free alloy. As a result, there is no possibility of Li plating. Even with current surges during operation, Li ions always either dissolve into the alloy to form a solid solution or leave the alloy in ionized form. This eliminates the possibility of plating, the risks associated with plating, and the resulting dendrite formation due to the growth of plated or deposited Li layers. The concept of this disclosure not only improves the safety and reliability of lithium metal batteries but also opens the way to a wide range of applications in next-generation energy storage systems. Regarding the reduction or inhibition of dendrite formation, maintaining crystallographic symmetry with metallic Li, i.e., maintaining a body-centered cubic (bcc) structure identical to metallic Li, and preserving optimal mixed enthalpy and interfacial energy at the electrode-electrolyte interface, has been identified as a major factor.

[0045] The MCA system provides a DC current collector for Li-ion batteries and Li-metal batteries. In certain embodiments, the MCA system represents a current collector without an anode. The MCA system is a substitute for copper (e.g., copper foil) as a current collector and metallic Li foil as an anode. The MCA system is suitable for direct use as a Li-containing solid solution MCA anode and as a Li-free MCA current collector. In certain embodiments, the density of the MCA system is about 50% lower than that of copper, thereby reducing the weight of the battery by 50%. Such an MCA system of the concept of the present disclosure includes the following features: (i) identical structure to Li, (ii) near zero, i.e., interface energy forming a solid solution, and (iii) less than 5% volume expansion.

[0046] Li metal has a bcc crystal lattice, and MCA is designed to have similar crystallographic symmetry with optimal interfacial energy and enthalpy of mixing, so that Li dissolves in the MCA and forms a solid solution instead of plating it. Furthermore, the MCA anode has a bcc crystal structure identical to that of high-purity metallic lithium in order to maintain lattice coherence during Li alloying and / or plating on the surface. According to the concept of this disclosure, crystallographic symmetry with metallic Li is maintained, i.e., a solid solution is formed that maintains a body-centered cubic structure (bcc) identical to that of metallic Li, and the interfacial energy is reduced to an optimal value that results in complete solid solution formation without inducing any phase separation or the formation of intermetallic alloys or intermediate structures. All alloys identified as MCA systems are identical to metallic Li and maintain bcc symmetry.

[0047] The MCA system comprises alloys of iron, aluminum, and magnesium. In certain embodiments, the MCA system alloy contains 40 atomic percent iron, 40 atomic percent aluminum, and 20 atomic percent magnesium, based on the total atomic weight of the alloy. In other embodiments, the MCA system alloy contains 10 atomic percent iron, 40 atomic percent aluminum, and 50 atomic percent magnesium. In further embodiments, the MCA system alloy contains 50 atomic percent iron, 40 atomic percent aluminum, and 10 atomic percent magnesium.

[0048] The MCA system also includes alloys of iron, gallium, and magnesium. In certain embodiments, the MCA system alloy contains 40 atomic percent iron, 40 atomic percent gallium, and 20 atomic percent magnesium, based on the total atomic weight of the alloy. In other embodiments, the MCA system alloy contains 10 atomic percent iron, 40 atomic percent gallium, and 50 atomic percent magnesium. In further embodiments, the MCA system alloy contains 50 atomic percent iron, 40 atomic percent gallium, and 10 atomic percent magnesium.

[0049] The preparation of the MCA system alloy involves drying iron, aluminum, and magnesium, for example, obtaining them in powder or granular form, and then performing high-energy mechanical grinding. The ground alloy powder is then prepared in pellet form, and the pellets are optionally cold-rolled into foil.

[0050] In certain embodiments, MCA is synthesized by a simple, scalable high-energy mechanical grinding and alloying (HEMM / HEMA) process. For example, powders of the elements Fe, Al, and Mg (or powders of the elements Fe, Ga, and Mg) are obtained in their atomic ratios and filled into grinding bottles. The ratio of powder to mill balls is kept constant at 1:1. A solvent (e.g., 10 ml of toluene) is added to the bottles containing the powder and mill balls to facilitate wet grinding, followed by HEMM / HEMA grinding for about 5 hours, with continuous 1-hour grinding intervals followed by a resting period of about 20 minutes. After grinding, the bottles are left open overnight in a fume hood to remove the solvent. The MCA powder is then dried in a vacuum oven (e.g., at 60°C for 6 hours) and stored in a vacuum dryer.

[0051] The HEMM / HEMA process facilitates the formation of metastable solid solutions due to the repeated crushing, welding, and re-welding of powder particles within a high-energy ball mill, which promotes rapid diffusion. Repeated high-energy collisions between the balls and powder particles result in the mixing of different elements at the atomic level, allowing for easy diffusion of elements and leading to the formation of metastable solid solution alloys of the desired composition. The intense mechanical deformation allows atoms of one element to dissolve into the crystal lattice of another element, forming a homogeneous solid solution. HEMM / HEMA of elemental powders of Fe, Al, and Mg or Fe, Ga, and Mg involves intense mechanical forces and high-energy collisions, resulting in the mixing of their atoms and the formation of metastable solid solutions with a body-centered cubic (bcc) crystal structure. The different crystal sizes of Fe, Al, Ga, and Mg result in the formation of nanocrystalline structures that further stabilize the bcc phase.

[0052] In a particular embodiment, the following MCA uses elemental powders in these atomic ratios: Fe 0.4 Al 0.4 Mg 0.2 (FAM442), Fe 0.5 Al 0.4 Mg 0.1 (FAM541), and Fe 0.1 Al 0.4 Mg 0.5These are prepared by incorporating (FAM145). These developed MCA systems offer a significant reduction in density, for example, more than 50% lower than conventional copper (Cu = approximately 9 g / cc) current collectors (e.g., FAM442 = approximately 4.6 g / cc, FAM541 = approximately 5.2 g / cc, FAM145 = approximately 2.7 g / cc).

[0053] Furthermore, in one embodiment, a powder sample of MCA is used as an active material containing polyvinylidene fluoride (PVDF) as a binder during slurry preparation and is used as an anode for a Li-metal as a counter electrode. MCA is used as an anode material for various Li-based batteries. Moreover, MCA pellets are effective as current collectors in anode-less systems. In one particular embodiment, MCA powders of the aforementioned alloys (Fe / Al / Mg and Fe / Ga / Mg) are formed into high-density pellets using uniaxial cold pressurization. Based on the electrochemical response, MCA demonstrates its effectiveness as a current collector in Li battery operation. In one particular embodiment, Fe 0.4 Al 0.4 Mg 0.2 The FAM442 offers superior performance as a reliable and efficient current collector in advanced Li-based battery technologies, particularly in innovative configurations such as anode-less systems.

[0054] The electrodes can be prepared on Cu foil using a standard slurry coating method. The slurry is prepared by mixing MCA powder as the active material with a binder and a solvent. The slurry is coated onto the Cu foil using conventional techniques. The slurry-coated foil is then dried. In a particular embodiment, the slurry is obtained by mixing 95% MCA powder and 5% PVDF using NMP as the solvent. The slurry is coated onto the Cu foil using a doctor blade. The slurry-coated foil is dried in a vacuum oven at about 80°C for about 12 hours.

[0055] In certain embodiments, the lithium-ion battery or lithium metal battery comprises a gel polymer electrolyte. In other embodiments, an electrolyte solution is used comprising lithium bis(trifluoromethane) sulfonimide (LiTFSI) salt (e.g., 1.0 M) in a 1:1 (vol / vol) mixture of solvents (e.g., dioxolane (DOL) and dimethoxyethane) containing LiNO3 (2 wt%) as an additive.

[0056] The MCA system of the concept described herein includes one or more of the following advantages: (i) The MCA alloy eliminates the need for separate current collectors and anodes, thus reducing the weight and overall weight of the battery. (ii) Using copper current collectors and metallic Li foil as anodes, eliminates the dendrite formation that tends to occur in current batteries. (iii) To achieve or increase weight capacity and volume capacity, (iv) Achieve more than 500 cycles without dendrite formation in the MCA alloy anode and current collector. [Examples]

[0057] <Example 1> <Section I: Theoretical Studies on Multicomponent Alloy Anodes (MCAs)> This study involved three components: 1. identifying the optimal MCA alloy anode system; 2. determining the solubility limit of alloyed Li; 3. determining the interfacial energy of alloyed Li with MCA; 4. determining the volume expansion of MCA due to solid solution formation associated with Li alloying; and 5. identifying elements that improve the diffusion of Li ions in MCA. These studies are described below.

[0058] <Computational study to identify the optimal MCA anode> Extensive first-principles studies were conducted to identify different compositions of multi-component alloy (MCA) anodes exhibiting high Li solubility and improved Li-ion conductivity.

[0059] <1. Phase stability of solid solution MCA> The phase stability of the bcc solid solution phase was studied because the MCA anode must have a bcc crystal structure identical to that of high-purity metallic lithium in order to maintain lattice coherence during Li alloying and / or plating on the surface. The total energy of the three possible completely disordered bcc, fcc, and hcp solid solution structures was studied for each specific composition of the alloy. The phase with the lowest energy is considered the most stable crystal structure among all three different crystallographic phases.

[0060] Fe 50 Zn 40 Mg 10 We synthesized a metastable bcc solid solution phase of the (FZM541) alloy, thereby demonstrating that the synthesis of this type of metastable structure is practical and experimentally feasible.

[0061] We selected alloy FZM541 as a benchmark for measuring the energy differences between various phases, and simultaneously, Fe 50 Al 40 Mg 10 Fe 40 Al 40 Mg 20 Fe 10 Al 40 Mg 50 Fe 10 Ga 40 Mg 50 Four other MCA compounds were adopted as the primary MCA anodes used for experimental synthesis and characterization. In the original Fe-based composition, FZM541, Fe and Zn are relatively heavy elements, so there was a compelling idea to replace Zn with Al, a lighter element, to improve the weight-to-weight capacity and reduce the Fe content in the alloying composition. The element Ga was chosen due to its flexibility, which can improve the Li diffusion rate through the compound.

[0062] To estimate phase stability, the following formula was used: ΔG f =[E tot (MCAfcc )]-E tot (MCA bcc ) ΔG f =[E tot (MCA hcp )]-E tot (MCA bcc ) ΔG f =[E tot (MCA bcc )]-E tot (MCA bcc )=0 In the following cases: ΔG f <0-phase is more stable than bcc ΔG f >0 phase is more unstable than BCC.

[0063] Instead of 100 atoms, for computational ease, we selected 96 atomic supercells consisting of 48 bcc and hcp base cells (2 atoms per cell): 4 × 4 × 3 = 48 cells and 24 fcc cubic cells (4 atoms per cell): 2 × 3 × 4 = 24 cells. All 96 atoms were randomly distributed across the 96 locations of the supercells in the following atomic ratios: 10 atoms for a nominal 10 atomic percent concentration, 20 atoms for 20%, 38 atoms for 40%, and 48 atoms for 50%. Note that such slight deviations from the model composition of the actual experimental compound did not significantly alter the general trends found in the computational studies.

[0064] The calculation method for this work is based on DFT using the Projector Extended Wave (PAW) format. The PAW base and projector functions were built using the Vienna Ab-initio Simulation Package (VASP). The exchange-correlation function was used in the Generalized Gradient Approximation (GGA) format. The Monkhorst-Pack scheme was used to sample the Brillouin zone and create a k-point grid for all MCA compounds used in the current study. The selection of an appropriate number of k-points in the irreducible portion of the Brillouin zone was done under the condition that the convergence of the total energy was restricted to 0.1 meV / atom. Relaxation procedures were used to optimize the internal positions of atoms and lattice constants within the supercell.

[0065] The relative phase stabilities of bcc, fcc, and hcp were calculated for all five alloying compositions. None of the compositions, including the experimentally synthesized FZM541, had a ground state with the highly desired bcc structure. This finding implies that all alloys should be metastable and therefore require careful crafting and specially engineered synthesis methods, maintaining a specific temperature range during their formation to ensure the stability of the metastable phase.

[0066] However, a comparison of phase stability between the already synthesized FZM541 phase and the other four proposed MCAs demonstrated similarities in ΔG values ​​between bcc and the most stable crystal structure. Fe 50 Al 40 Mg 10 Fe 40 Al 40 Mg 20 , and Fe 10 Ga 40 Mg 50 These three MCAs demonstrate ΔG similar to or even smaller than that of FZM541, suggesting that all of these compounds, like FZM541, can also be synthesized in the bcc phase. 10 Al 40 Mg 50Only this compound exhibits a ΔG slightly larger than that in the case of FZM541, and as demonstrated and shown by the experiments of the present inventors discussed in the experimental section (Section II), this does not constitute a significant obstacle to the experimental synthesis of this compound.

[0067] <2.Li Solubility in MCA Anodes> Furthermore, first-principles methods were applied to study Li solubility in all five metastable compositions. For these purposes, a 250-atom [5×5×5] bcc supercell was selected, and the Li solubility limit in the studied compositions was evaluated using the following relationship: ΔG f =E tot (MCA 1-x Li x )-[(1-x)E tot (MCA)+xE tot (Li bcc )] ΔG f <0-solid solution, ΔG f >0-phase separation.

[0068] The calculated ΔG of different MCAs as a function of Li content shows that in Fe 50 Zn 40 Mg 10 (FZM541) alloy, only approximately 33 atomic % of Li (corresponding to a Li areal capacity of approximately 21 mAh / cm 2 ) can be homogeneously dissolved for a mass equivalent to that of 100-micron-thick copper, which is a preferred current collector in conventional Li-ion batteries. However, solid solution alloys exhibiting higher Li solubility have been developed, demonstrating the possibility of achieving higher areal capacity for lithiated alloy structures without inducing any phase separation.

[0069] Fe 50 Al 40 Mg 10 and Fe 40 Al 40 Mg 20 The calculation of Li solubility in the structures of Fe 40 Al 40 Mg20 and Fe 50 Al 40 Mg 10 It has been shown that up to 53 and 62 atomic percent of Li can dissolve in the alloys.

[0070] Accordingly, these two alloys have higher Li solubility and lower atomic weight than FZM541, which is highly likely to contribute to achieving a higher specific capacity for the anode. Therefore, these alloys can function as current collectors and anodes for next-generation high energy density Li-ion batteries.

[0071] Furthermore, Fe 10 Ga 40 Mg 50 (density: about 4 g / cc), Fe 40 Al 40 Mg 20 (density: about 5.2 g / cc), and Fe 10 Al 40 Mg 50 (density: about 2.74 g / cc) are much lighter than Fe 50 Zn 40 Mg 10 (about 7 g / cc) and Cu (about 9 g / cc). These alloys can be used to significantly reduce the weight of the finally packaged battery, which is an additional advantage over currently used Li-ion batteries.

[0072] <3.Interfacial Energy of MCA Alloys> One of the main conditions for an anode where dendrites do not form is A x B y C 1-x-y is the interfacial energy between a metallic Li layer having various MCA compositions expressed as above and the alloyed metal surface. Using a macroscopic atomic model, such an interface was estimated from the following formula: [Formula] - Partial interfacial energy between Li and metal A.

number

number

number

[0073] For 5 atoms of Li, the interfacial energy ΔH is present in all non-lithium-treated MCA alloys under consideration. int The results are summarized in Table 1. The lowest ΔH int Fe 10 Al 40 Mg 50 and Fe 10 Ga 40 Mg 50 Therefore, these compounds are the most optimal from the standpoint of suppressing dendrite formation.

[0074] solubility limit x lim For calculating the interfacial energy of Li above this value, the formula is slightly modified as shown below:

number

number

[0075] <4. Volume expansion of lithium-treated MCA anodes> The volume expansion of lithium-treated alloys versus non-lithium-treated alloys depends on the atomic radii of the metallic components of the alloy and the atomic radius of Li. For example, Fe 40 Al 40 Mg 20 The atomic metallic radii of Fe, Al, and Mg are 1.26 Å, 1.43 Å, and 1.60 Å, respectively. Therefore, Fe 40 Al 40 Mg 20 , R av The average atomic radius is [1.26 3 ×0.4 + 1.43 3 ×0.4 + 1.6 3 ] 1 / 3 = 1.41 Å. Considering the atomic radius of Li, R Li = 1.52 Å, and the volume expansion during alloying of Li to the alloy is as follows: [Rav 3 (1-x)+R Li 3 x] / R av 3 (1-x) = 1 + 1.258x / (1-x), where x is the Li content. Therefore, the percentage change in volume is given by: Volume expansion coefficient ΔV%: [1.258x / (1-x)] * 100%.

[0076] With respect to this function and the corresponding relationship, at high Li content (50 atomic%), the volume expansion coefficient ΔV reaches 126%, which is quite large (the total volume more than doubles). However, at lower Li content (about 20 atomic%), ΔV is within about 30-31%. Furthermore, as described in Section II, Fe 40 Al 40 Mg 20 Experimental observations of the synthetic alloy showed that 1 mg of Li produced 4 mAh / cm³ of lithium. 2 To achieve a surface capacity of 6mAh / cm², 2 To achieve the desired area capacity of Li, 1.5 mg of Li is equivalent. 183 mg of Fe has an atomic mass of 38 gram atoms / mol. 40 Al 40 Mg 20 Using the fabricated high-density pellets, the molar percentage of alloyed Li is 4.3 mol%, corresponding to a volume change of approximately 5.6%, which can be easily withstood by the system without causing phase separation, without degradation associated with electrode volume expansion, and while maintaining the original bcc crystal structure. Even if a larger amount of Li is alloyed into the system, the volume change is probably only about 5-10%, which can be easily withstood by the alloy and does not result in the degradation or cracking typically seen in Zintl alloy phases encountered in Si and Sn anodes, which cause enormous volume changes of 300-400%. This is another feature of the present invention and the identified multi-component alloy (MCA).

[0077] <5. Li-ion mobility at the MCA anode> Li ion mobility in the MCA anode is one of the critical properties of a compound necessary for efficient electrode cycling. Impeded Li ion mobility within the anode can lead to very poor cycling. To estimate Li ion mobility in various MCAs, it is necessary to calculate the activation energy barrier during lithium atom hopping between two adjacent unit cells in the crystal lattice via the vacancy-hopping diffusion mechanism.

[0078] The computational model for calculating the activation barrier consists of two body-centered cubic (bcc) elemental unit cells having alternating atomic layers of Li and the probed metal layer. In model (a), a Li atom located at the center of a cubic bcc unit cell moves through the intermediate atomic layer to an adjacent Li vacancy. Simultaneously, the Li vacancy moves in the opposite direction. In model (b), for high-purity Li metal, the intermediate layer consists only of Li atoms. For the calculation of the activation energy, the E of Li ions in high-purity Li and the studied MCA, and in other metal components in models (a) and (b) is calculated. a The following methods were used. All calculations were performed using the Climbing Image Nudge Elastic Band Method (CINEB), also implemented in the VASP calculation package within the Projector Extended Wave (PAW) method, and the Generalized Gradient Approximation (GGA) for the exchange-correlation energy function in forms known in the art. The total path of Li ions between the centers of both adjacent unit cells was divided into eight equally spaced sections, along with the calculation of the total energy of the system at each continuum point from the start to the end of this path. For all calculations, a 2×2×2 supercell was assumed to consist of eight basic bcc unit cells, each containing one Li vacancy, seven Li atoms, and eight atoms of the other metal constructed. For high-purity Li metal, the structure contained one vacancy and fifteen Li atoms. The Monkhorst-Pack scheme was used to sample the Brillouin zone and create a k-point grid for all Li alloys used in the current study. The selection of an appropriate number of k-points in the irreducible portion of the Brillouin zone was made under the condition that the convergence of the total energy be limited to 0.1 meV / atom.

[0079] The calculated potential energy profiles for different alloying elements were derived. All potential energy graphs have similar profiles with a maximum energy value located in the middle of the Li hopping path, corresponding to the activation barrier for each particular alloying element. According to these results, the Li mobility in the modeled Mg and Zn bcc metals is even slightly higher than that of high-purity Li-bcc, likely due to the lower cohesive energy of high-purity Mg and Zn compared to high-purity Li (E a The low barrier allows Li atoms to easily diffuse through the Mg and Zn planes, thus easily resulting in high overall Li ion conductivity / mobility in high-purity Mg and Zn metals. This graph also shows that Na further reduces the activation barrier for Li migration through the lattice compared to metallic Mg and Zn.

[0080] On the other hand, Fe, Al, and Ga increase the activation barrier of the Li ion hopping pathway. This is due to the higher Fe-Fe, Al-Al, and Ga-Ga interatomic bonds within the corresponding intermediate layers.

[0081] Table 2 also summarizes the average activation barrier E of all MCAs considered in the study. a This is the lowest E. a av (The highest Li mobility is Fe 50 Zn 40 Mg 10 Fe 10 Ga 40 Mg 50 , and Fe 10 Al 40 Mg 50 This can be demonstrated by the MCA system. [Table 2]

[0082] Therefore, this computational study was useful in estimating the different physical properties of various MCA anodes. These properties include phase stability, interfacial energy, Li solubility limit, volume expansion, and Li ion mobility through the MCA. The theoretical studies described above formed the basis for the experimental studies performed to verify the results of the theoretical and computational studies described in Section II below.

[0083] <Section II: Experimental Study of Novel Multi-Component Alloy (MCA) Anodes and Current Collectors that Do Not Form Dendrites for Li-ion Batteries> This study includes all experimental studies conducted on the three MCA systems identified by the theoretical studies described earlier in Section I.

[0084] <Experimental Section> MCA was synthesized by a high-energy mechanical grinding and alloying (HEMM / HEMA) process. Powders of the elements Fe, Al, and Mg were taken in their respective atomic ratios and filled into grinding bottles. The ratio of powder to mill balls was kept constant at 1:1. 10 ml of toluene was added to the bottles containing the powder and mill balls as a solvent to facilitate wet grinding, followed by HEMM / HEMA grinding for approximately 5 hours in continuous 1-hour intervals, after which a resting period of approximately 20 minutes was allowed. After grinding, the bottles were left open overnight in a fume hood to remove the solvent. The MCA powder was then dried in a vacuum oven (60°C for 6 hours) and stored in a vacuum dryer. Various MCAs (Fe 0.4 Al 0.4 Mg 0.2 (FAM442), Fe 0.5 Al 0.4 Mg 0.1 (FAM541), and Fe 0.1 Al 0.4 Mg 0.5(FAM145) was prepared by incorporating elemental powders in their atomic ratios. These developed MCA systems offer a significant reduction in density, more than 50% lower than conventional copper (Cu = approximately 9 g / cc) current collectors (FAM442 = approximately 4.6 g / cc, FAM541 = approximately 5.2 g / cc, FAM145 = approximately 2.7 g / cc).

[0085] MCA powder samples were used as an active substance containing PVDF as a binder during slurry preparation and as an anode for Li metal as a counter electrode in initial electrochemical tests. This demonstrated its potential as an anode material for various Li-based batteries. MCA pellets were prepared and used for electrochemical tests to evaluate the potential effectiveness of MCA as a current collector in anode-less systems. MCA powder was formed into high-density pellets using uniaxial cold pressing. FAM442 was selected as a representative material among the various MCA materials tested to further investigate its potential as a current collector. Based on the preliminary electrochemical response of MCA, FAM442 showed superior performance compared to other MCAs and was therefore considered to demonstrate effectiveness as a current collector in battery operation. FAM442 powder was prepared into pellets and investigated whether it functions as a reliable and efficient current collector in advanced Li-based battery technologies, particularly in innovative configurations such as anode-less systems.

[0086] First, gallium (Ga) was explored as a chemical additive for obtaining thick, high-density pellets. 5 wt% Ga (10 mg) was added to a mortar pestle along with 95 wt% FAM442 (190 mg) powder, stored in an oven at 60°C, and mixed to obtain a homogeneous powder mixture. This powder mixture was then processed using pellet-making dies (diameters 1.3 cm, 1.32 cm). 2The pellets were filled into a die and subjected to uniaxial cold pressurization at 40°C at various pressures for 1 hour. Ga was used as a low-temperature liquid-phase sintering agent because its melting point is below 30°C. As a result, high-density pellets (PFAM442-G) were obtained using 5 wt% Ga under optimized process parameters (holding cold pressurization at 40°C and 250 psi for 2 hours). When the Li ion storage capacity of the PFAM442-G pellets was tested, it was observed that the Ga used as a sintering agent to form the pellets tended to form intermetallic compounds with Li ions, affecting the electrochemical performance of the pellets in the initial cycle. Therefore, high-purity pellets of 100% FAM442 (PPFAM442) were synthesized by avoiding the use of any sintering agent that would affect the electrochemical performance of the MCA pellets. The uniaxial pressurization process conditions for pellet synthesis were optimized. Generally, 200 mg of FAM442 powder synthesized by HEMM / HEMA was weighed and transferred to a pellet production die. Next, the dies were loaded into uniaxial presses and held at temperatures and pressures of 110°C and 6750 psi for 5 hours, respectively, to obtain high-density pellets of FAM442. The pellets were then collected and stored in a vacuum dryer until electrochemical testing was performed. 116 mg / cm³ 2 Area load, 0.5 cm 2 PPFAM442 pellets were prepared for in-situ XRD measurements using optimized pellet preparation process conditions with a surface area and a thickness of 200–400 mm.

[0087] <Structural and electrochemical characterization> The phase structure characteristics of the samples were obtained using an X-ray diffractometer (XRD) (Empyrean: Malvern Panalytical) with Co radiation. Wavelength correction was performed to convert the patterns to show Cu-Ka radiation. The electrochemical properties of various MCA alloys were evaluated in both coin cell and pouch cell configurations. Electrodes were prepared on Cu foil by a standard slurry coating method. The slurry was obtained by mixing 95% MCA powder as the active substance, 5% PVDF as the binder, and NMP as the solvent, and coated onto the Cu foil using a doctor blade. The slurry-coated foil was dried in a vacuum oven at 80°C for 12 hours. Electrodes for testing in the coin cell configuration were 0.5 inches (1.26 cm) in diameter. 2 The circular disks were obtained by perforating them. Coin cells were fabricated using CR2032 with various MCA (FAM541, FAM442, and FAM145) electrodes as working electrodes, polypropylene separator disks, and Li foil as reference and counter electrodes. The electrolyte solution was prepared by dissolving 1.0 M lithium bis(trifluoromethane)sulfonimide (LiTFSI) salt in a 1:1 (vol / vol) mixture of dioxolane (DOL) and dimethoxyethane as solvents, containing 2 wt% LiNO3 as an additive. The electrolyte volume was kept constant at 60 μL throughout the electrochemical tests in the coin cells.

[0088] The coin cells were also fabricated using high-purity, high-density FAM442 pellets and Ga as the sintering agent, with area loads of 135-142 mg / cm². 2 and 145.4 mg / cm³ 2 Li foil was used as the counter electrode. The amount of electrolyte used was kept constant at 60 mL, which resulted in an extremely low electrolyte-to-active substance ratio.

[0089] For single-layer pouch cell fabrication, cut the FAM442 electrode to 20cm using an electrode cutting machine. 2The cells were cut into rectangles (4 cm and 5 cm) with the following areas: The area loading of the active substance (FAM442) in the pouch cell electrode was 9.2 mg / cm². 2 The single-layer electrode was surrounded by a PP separator. A pouch cell bag (multilayer laminated material) was prepared by cutting and heat sealing, thereby creating a cavity to hold the electrode assembly. Li foil (50 mm thick) was used as the counter electrode and reference electrode for the pouch cell test. 400 mL of electrolyte was used in the pouch cell test, resulting in an extremely low electrolyte-to-active-substance ratio. The MCA electrode surrounded by the separator was assembled against the Li foil, then this assembly was loaded into the pouch cell bag, filled with electrolyte, and the pouch cell was sealed. The fabricated pouch cells were left to rest for 24 hours before the electrochemical test. The electrochemical performance of various MCA electrodes was measured using the Arbin Potentiostat (electrochemical workstation).

[0090] <Results and Discussion> HEMM / HEMA facilitates the formation of metastable solid solutions due to the repeated crushing, welding, and re-welding of powder particles within a high-energy ball mill. Repeated high-energy collisions between the balls and powder particles result in the mixing of different elements at the atomic level, leading to the formation of solid solutions. Intense mechanical deformation allows atoms of one element to dissolve into the crystal lattice of another element, forming a homogeneous solid solution. HEMM / HEMA of elemental powders of Fe, Al, and Mg involves intense mechanical forces and high-energy collisions, resulting in the mixing of their atoms and the formation of solid solutions with a body-centered cubic (bcc) crystal structure. The different crystal sizes of Fe, Al, and Mg lead to the formation of nanocrystalline structures that further stabilize the bcc phase. XRD patterns were obtained for all synthetic MCA in powder and pellet forms. Each shows the Fe after grinding. 0.4 Al 0.4 Mg 0.2 (FAM442) and Fe 0.5 Al 0.4 Mg 0.1The XRD pattern of the (FAM541) powder sample showed two peaks around 2θ values ​​of 44.5° and 65°, corresponding to the nanocrystalline bcc phase confirming the formation of a solid solution in HEMM / HEMA. The Li metal has a bcc crystal lattice, and the MCA is designed to have similar crystallographic symmetry with optimal interfacial energy and enthalpy of mixing so that Li dissolves in the MCA and forms a solid solution instead of plating it. Fe 0.1 Al 0.4 Mg 0.5 The XRD pattern of (FAM145) showed a small bulge around a 2θ value of 44.5° demonstrating the initiation of bcc phase formation after 5 hours of HEMM / HEMA, although not all elements had fully reacted. The formation of the bcc phase indicates that the method contributes to the formation of a metastable structure to demonstrate the feasibility and validity of the concept of this disclosure. The XRD patterns of pellets synthesized using Ga as a sintering agent (PFAM442-G) and pellets synthesized using high-purity powder of FAM442 (PPFAM442) showed two peaks around 2θ values ​​of 44.5° and 65°, respectively, indicating the presence of a nanocrystalline bcc phase and suggesting that process parameters for synthesizing pellets via uniaxial cold pressurization do not adversely affect the material structure.

[0091] In-situ XRD measurements of PPFAM442 were performed during cell operation to investigate whether lithium plates formed on the surface of the FAM442 pellets or solid solutions formed with the alloy. Based on these measurements, Li foil (area 0.785 cm²) was examined in a glove box. 2 A special EL cell was fabricated using a material with a thickness of 600 mm. The PPFAM442 inside the EL cell was set to 0.25 mA / cm². 2 It charges at a current density of 3.75 mAh / cm². 2 This area capacity was achieved. XRD measurements were performed at 15-minute intervals during cell operation. The XRD patterns of the pellet were collected over 15 hours while Li ions were charging it, and are shown in Figure 1. The 15-hour cycle from Figure 1 (approximately 3.75 mAh / cm², corresponding to 1 mg of Li) 2Even after the process, there is no evidence of peaks corresponding to metallic Li or any Li-related alloys or compounds, suggesting that Li ions formed a solid solution with the FAM442 pellets.

[0092] <A.Electrochemical evaluation of slurry-coated MCA as a dendrite-free anode for Li-based batteries> 1)Fe 0.1 Al 0.4 Mg 0.5 (FAM145) Figure 2 shows the electrochemical Li ion storage in a slurry-coated FAM145 electrode using lithium foil as the counter electrode and reference electrode in a coin cell. 2~3 mg / cm 2 FAM145 electrode with an active material loading of (1.26 cm 2 ), Li ions were provided at various charging rates ranging from 1 mAh to 20 mAh over 31 cycles each. Initially, the electrode was cycled at a current of 1 mA for 31 cycles, starting from 1 hour of charging / discharging, then increasing stepwise by 1 hour up to 10 hours. After that, the cell was further cycled at a current of 3 mA for 4 hours and 5 hours respectively over 31 cycles. In addition, to investigate the limit of the solid solution alloy of MCA with Li, the charging rate of the electrode was increased to achieve 18 mAh and 20 mAh over 31 cycles each. The FAM145 electrode demonstrated not only the ability to store high Li charge storage via solid solution formation, but also long cycle stability at low and high charging rates. FAM145 showed prospect of being used as an alternative anode material for advanced energy storage batteries with longer and more stable service life and no dendrite formation. The electrode was subjected to continuous electrochemical evaluation for over 4500 hours for lithium charge storage. The electrode showed the ability to store up to 20 mAh of Li, corresponding to approximately 5 mg of Li, without showing signs of dendrites.

[0093] Initially, the energy efficiency of the FAM145 electrode was relatively low, which may be due to SEI formation and the initial diffusion barrier preventing Li ions from entering the bcc phase of the MCA solid solution. In addition, the XRD pattern of FAM145 confirmed that it consisted of a mixed phase of bcc and a metallic element phase corresponding to unreacted elements, which may also contribute to the lower Coulomb efficiency. However, as the cycle progressed further, the Li ions filled their pathways, stabilizing the system, opening the crystal lattice of the MCA alloy, facilitating Li ion diffusion and forming a solid solution. As a result, the energy efficiency of the FAM145 electrode was 100% from a 5 mAh charge storage of Li ions. Computational studies showed that FAM145, with a Li solubility of 37 atomic% and a partial bcc crystal lattice, possessed the most optimal interfacial energy (0.07 kJ / mol), and therefore these electrodes exhibited stable and reversible Li cycling at higher charge rates.

[0094] Figure 3 shows the Li charge storage response of the FAM145 electrode at charging speeds of 1 mAh (Figures 3a-c) and 5 mAh (Figures 3d-f). Figures 3a and 3d show the response over 31 cycles for charging 1 mAh and 5 mAh, respectively, at 1.26 cm². 2 The voltage profile curves and area capacitance of a FAM145 electrode with the given electrode surface area are shown. Figures 3b-3c and 3e-3f show the voltage profiles of the electrode for the first and 31st cycles at 1 mAh and 5 mAh charges, respectively. The first voltage profile of the FAM145 at a 1 mAh charge shows a diffusion curve indicating the resistance faced by Li ions during the initial insertion into the FAM145 structure. The overvoltage of the coin cell in the initial cycle is higher (approximately 0.34 V) due to this initial diffusion resistance for Li ions and the formation of a solid electrolyte interphase (SEI) layer on the electrode surface (Figure 3b). However, the overvoltage decreases to approximately 0.16 V after 31 (Figure 3c) cycles of continuous charging and discharging of the cell. As the cycle continues at 5 mAh, the overvoltage further decreases to approximately 0.1 V after 31 cycles of 5 mAh charging (Figure 3f).

[0095] Figure 4 shows the electrochemical evaluation of the FAM145 electrodes at higher charge rates of 12mAh and 18mAh. Prior to connection at these charge rates, the cells had already been cycled for over 3400 hours at different charge rates, as shown in Figure 2. Figures 4a-c and 4d-f show the Li storage of the FAM145 at higher charge storage rates of 12mAh and 18mAh. As is evident from these curves, the FAM145 can reversibly store Li with 100% energy efficiency even at higher charge storage rates, although overvoltages may be higher due to electrolyte consumption and increased overall cell impedance.

[0096] Computational studies have revealed that the solubility limit of FAM145 for forming a solid solution with Li ions is 37 atomic percent. (2-3 mg / cm³) 2 Under load, the FAM145 alloy with a charge-storage rate of 18 mAh exceeded its solubility limit, yet the electrode was able to reversibly cycle Li ions at a much higher rate. Computational studies further revealed that the interfacial energy of FAM145 above the Li solubility limit is even more favorable for uniform Li deposition without dendrite formation (Table 1). As a result, the FAM145 electrode can plate Li ions beyond its solubility limit and store them through the formation of a solid solution and uniform Li deposition thereon. The electrode demonstrated long-term stability, successfully storing up to 20 mAh (equivalent to approximately 5 mg of Li) without any signs of dendrite formation during over 4,500 hours of cycle testing during electrochemical evaluation. The results of these electrochemical studies demonstrate high capacity and stability, demonstrating FAM145 as a potential anode material to ensure safe and reliable operation of lithium metal batteries.

[0097] 2. Fe 0.5 Al 0.4 Mg 0.1 (FAM541) Figure 5 shows the complete formation of a high-purity bcc phase and the Li-ion storage performance of the FAM541 electrode with an optimal interfacial energy of 1.8 kJ / mol. Calculation studies predicted that FAM541 would exhibit the highest Li solubility of 62 atomic% when forming a solid solution. Figures 5a, 5d, and 5f show the results over 30 cycles at 1,2, and 4 mAh charges, respectively, at 1.26 cm³. 2 The voltage profile curves and area capacitance of the FAM541 electrode with the electrode surface area are shown. Figures 5b-c, 5e-f, and 5h-i show the voltage profiles of the electrode for the first and 30th cycles at charges of 1, 2, and 4 mAh, respectively. Similar to the FAM145, the first voltage profile of the FAM541 at a 1 mAh charge also shows a diffusion curve indicating the resistance presented during the initial insertion of Li ions into the FAM541 bcc structure. The overpotential of the coin cell in the initial cycle is higher (approximately 0.285 V) due to this initial diffusion resistance for Li ions and the formation of a solid electrolyte interphase (SEI) layer on the electrode surface, and decreases by approximately 0.09 V over the 30-cycle cycle. The bcc crystal lattice of the FAM541 must be open to allow Li ions to occupy atomic sites in the lattice, thus presenting an initial diffusion limit for Li ion migration. Once the lattice stabilizes, opens, and Li ions occupy the atomic sites, pathways are created for the Li ions to easily diffuse in subsequent cycles and reoccupy the sites. The FAM541 electrode exhibits much lower overpotential when cycled to store 2 and 4 mAh Li-ion charges. Thus, the overpotential of the FAM541 electrode tends to decrease with cycles, as is evident from the first and third voltage profiles of the cell at 2 (Figures 5e-f) and 4 mAh charges (Figures 5h-i). The electrode also exhibits reasonable energy efficiency during cycling, thus demonstrating the potential of the FAM541 to be used as an anode for Li-ion storage for advanced battery technologies.

[0098] 3. Fe 0.4 Al 0.4 Mg 0.2 FAM442 a. Performance evaluation of coin cells Figure 6 shows the electrochemical storage performance and response of Li-ion storage at various charging rates for slurry-coated FAM442 electrodes (95% active material and 5% PVDF as binder), ranging from 2 to 4 mg / cm³. 2 Electrodes with area loadings were tested in coin cell configuration mode to first investigate their electrochemical performance. FAM442 showed complete formation of a high-purity bcc phase exhibiting an optimal interfacial energy of 1.4 kJ / mol (Table 1) and a Li solubility limit of 53 atomic%. The electrodes were evaluated for their Li storage at various charging rates ranging from 1 mAh to 18 mAh, as shown in Figure 6. The FAM442 electrodes demonstrated the ability to reversibly store Li ions by forming solid solutions up to 18 mAh, equivalent to approximately 4.5 mg of Li. The electrodes were cycled for charges of 1, 2, 4, and 6 mAh over 30 cycles each, followed by increasing the charge to 8 mAh and cycling over 100 cycles. The cells showed reasonable charge storage by forming solid solutions with Li ions.

[0099] Subsequently, following these studies to investigate the structural robustness of FAM442, the cells were tested with an 8mAh charge, left idle for 30 days, and then tested again with a 10mAh charge over 200 cycles. The electrodes showed 100% energy efficiency, no nucleation or growth overpotential indicating the formation of a complete solid solution until the Li solubility limit was reached, and thereafter showed uniform Li plating without the formation of dendrites due to even lower interfacial energies. Thus, the electrodes achieved 14.5mAh / cm² with an 18mAh charge. 2 Furthermore, it was possible to reversibly store Li ions, which provided a reversible area capacity.

[0100] Similar to previous MCAs, FAM442 also exhibited an initial diffusion barrier for Li ions to occupy atomic sites in the bcc lattice (Figures 7a-c). Consequently, the cell overpotential is relatively high and energy efficiency is low during the initial cycle phase. However, as the cycle progresses (Figures 7d-f), the crystal lattice of FAM442 is stabilized by the introduction of Li ions, which open pathways for occupying atomic sites in the lattice structure, facilitating Li ion diffusion and leading to openings in the alloy structure that form a solid solution alloy. Thus, after the crystal lattice is fully opened, Li ions readily dissolve into the alloy, continuing to form a solid solution without any nucleation and growth overpotential. As a result, the FAM442 electrode dissolves and extracts Li ions from the bcc phase at a relatively constant potential, as seen in the cell voltage profiles in Figures 7e-f and 7h-i.

[0101] The electrochemical performance evaluation of FAM442 in a coin cell configuration suggested that further testing in larger and more complex pouch battery configurations is feasible. Figure 8 shows the evaluation of a single-layer pouch cell of FAM442 at a charging rate of 9 mAh over 100 cycles. The pouch cell electrode was measured at 9.15 mg / cm². 2 With area load of 20cm 2was cut to the area, and cells were fabricated in a tandem glove box with an electrolyte volume of 400 mL. The voltage profiles and area capacity values over 100 cycles are presented in Figure 8a, and the voltage profiles for the 1st and 100th cycles are shown in Figures 8b-c. The performance of the pouch cell is consistent with the electrochemical evaluation of the coin cell. The pouch cell showed signs of an initial diffusion kinetic barrier for Li ions, and exhibited initial resistance that occupied atomic sites to open the bcc crystal lattice of FAM442, which promotes the subsequent facile diffusion of Li ions. As a result, the energy efficiency is lower in the initial cycles and increases to 97% after 35 cycles. In addition, the overvoltage is relatively higher in the first cycle (about 0.08 V) and decreases to about 0.072 V after 100 cycles. Consistent pouch cell electrochemical evaluation of FAM442 shows that its properties are consistently reliable across different cell formats. This suggests that the FAM442 alloy maintains its structural integrity, electrochemical stability, and ability to suppress dendrite formation even when scaled up from the smaller, controlled environment of a coin cell to a more practical and commercially relevant pouch cell configuration. Such consistency indicates that FAM442 is suitable for incorporation into commercial lithium metal batteries without significant performance degradation during scale-up.

[0102] <B.Electrochemical Evaluation of FAM442 Pellets as Dendrite-Free Current Collectors for Li-Based Batteries> After successfully demonstrating FAM442 as a dendrite-free anode material for advanced Li-based batteries, the performance of FAM442 when used as a current collector in anode-free systems was evaluated. We used cold uniaxial pressing to consolidate FAM442 powder into thick (200~1000 μm), high-density pellets. First, pellets were prepared using Ga as a liquid phase sintering agent. In addition, pellets were also prepared using high-purity FAM442 powder by optimizing pellet processing conditions.

[0103] 1) FAM442 Pellets Using Ga as a Sintering Agent The XRD patterns of high-purity pellets synthesized using Ga match those of the powder sample, suggesting that the crystallographic structure of the material remains intact during the compression process. Figure 9 shows the results when Ga(PFAM442-G) was used as the sintering agent at a concentration of 145.4 mg / cm³. 2 Pellets prepared by area loading (1.32 cm 2 The electrochemical performance of the surface area (thickness 200-400 mm) is shown over 110 cycles at various charging rates ranging from 1 mAh to 8 mAh. The PFAM442-G pellets were charged at 1, 2, 4, 6, and 8 mAh rates (Figure 9), and the area capacity and voltage curves for 1, 4, and 8 mAh are shown in Figures 10a-i. Initially, pellets prepared using Ga exhibit low energy efficiency at 1 mAh charge for up to 50 cycles, due to Li ions forming an intermetallic alloy containing Ga, as can be seen in the voltage profiles in Figures 10a-c. At this stage, Li ions not only form a solid solution with PFAM442 but also an alloy with Ga (Figures 10a-c). However, as the cycles progress, the pellet surface stabilizes, and the Li ions tend to dissolve into PFAM442-G, showing no signs of alloying with Ga (Figures 10d-i). Li ions enter and occupy the voids in the bcc lattice structure of PFAM442-G, forming a solid solution. The complete formation of the solid solution in the Li-containing pellet eliminates the need to overcome nucleation and growth overpotentials during the charge and discharge cycles of the cell operation, resulting in constant voltage dissolution and extraction of Li ions. Overpotentials in Li ion dissolution and extraction are also reduced in each cycle of the cell's overall cycle performance. The pellet has a flow rate of 6 mAh / cm². 2 It has been demonstrated to provide a high area capacity exceeding 440 cycles and exhibits long cycle stability exceeding 440 cycles. Corresponding to the solubility limit of FAM442, which is 53 atomic%, the pellet has a capacity of 114-120 mAh / cm³. 2A solid solution having Li equivalent to the area capacity can be formed. The electrochemical performance of PFAM442-G is consistent with that of the powder sample, but the Ga used as a sintering agent to form the pellets tends to form an intermetallic alloy structure with Li ions, thus affecting the electrochemical performance of the pellets. Therefore, to avoid the use of any sintering agent that affects the electrochemical performance of the MCA pellets and to explore the performance of a high-purity system without any sintering agent, high-purity pellets of 100% FAM442 (PPFAM442) were synthesized.

[0104] 2) High-purity pellets of FAM442 High-purity pellets of untreated FAM442 were prepared without sintering additives by optimizing the process parameters (110°C, 6750 psi, 5 hours) for uniaxial pressurization. Subsequently, coin cells versus Li metal foils were fabricated using the high-density, thick PPFAM442 pellets to evaluate their potential for use as current collectors. The pellets were 1.32 cm² thick. 2 138.6 mg / cm³ 2 The area load and thickness of 200-400 mm were shown. PPFAM442 exhibits an XRD pattern similar to that of the powder sample corresponding to the formation of the bcc solid solution phase. The electrochemical performance of this pellet is shown in Figure 11, along with a digital image of PPFAM442 in the insert in Figure 11a. A coin cell with PPFAM442 pellets was measured at 1 mA / cm². 2 Charging at this current density, it can exceed 250 cycles, with a capacity of 5mAh / cm². 2The area capacity was achieved. The energy efficiency of the cell is low in the first few cycles due to the resistance presented to Li ions to occupy atomic sites in the alloy's bcc crystal lattice. Due to this initial dynamic barrier, the cell exhibits high overpotential during the first few cycles. However, after the complete solid solution lattice formation of Li ions with the alloy, the overpotential is significantly reduced, and the energy efficiency increases to 100% beyond 250 cycles during the subsequent dissolution and extraction of ions. This indicates that the charge-discharge process is very efficient and there is no significant loss of lithium ions due to side reactions or other inefficiencies. Figures 11b-11f show the voltage profile of the cell and illustrate the evolution of overpotential with cycles. The overpotential decreases significantly with cycles because the formation of a complete solid solution results in improved electrochemical kinetics, leading to a faster charge and discharge process with easier diffusion of Li ions. The results demonstrate that PPFAM442 is very effective in facilitating reversible lithium storage without loss, decomposition, or safety risks, and no dendrites are formed. These results are for FAM442(Fe 40 Al 40 Mg 20 This MCA system demonstrates the potential for use as a current collector in advanced lithium-ion batteries (LIBs) or lithium metal batteries (LMBs) in anode-less systems.

[0105] 3) Pre-lithium-treated, high-purity pellets of FAM442 as a Li-ion reservoir The above section described the performance of PPFAM442, demonstrating the potential of FAM442 as a current collector in LIBs and LMBs. However, the pellets still exhibited an initial kinetic diffusion barrier for Li ions to occupy the voids in the lattice structure and form a solid solution. To minimize this initial barrier, a new pellet was synthesized (surface area 1.32 cm²). 2 , 140.9 mg / cm³ 2The pellet was sequentially subjected to pre-lithium treatment at constant current and constant voltage (CCCV) (200-400 mm). The CCCV process is expected to force Li ions into the atomic voids of the alloy's crystal lattice, enabling the formation of a complete solid solution. The pellet was initially subjected to 1 mAh / cm³. 2 Regarding 0.5mA / cm 2 The pellet was charged at a constant current (CC) density, and then the potential (CV) was held at -0.2V until the current dropped to C / 10. Subsequently, the pellet was charged again at 4mAh / cm². 2 Regarding 1 mA / cm 2 The pellets were charged with CC and the potential was held at -0.2V until the current dropped to C / 10. Similarly, pellets were charged to 9 and 1 mAh / cm². 2 The pellets are sequentially charged using CCCV, and the charge rate is 15mAh / cm². 2 The lithium ions were cumulatively charged. Then, the output was 15 mAh / cm². 2 This pre-lithium-treated pellet, containing Li equivalent to approximately 3.75 mg of Li, was used as a Li reservoir during cell operation. Li ions from the pellet were then supplied at 2 mA / cm². 2 Cycle processing at a current density of 6mAh / cm² 2The area capacity was achieved and deposited on the opposing Li metal anode, demonstrating the potential of PPFAM442 as a current collector in anode-less systems, the results of which are shown in Figure 12b. The energy efficiency of the cell is evaluated as delamination or dealloying from the solid solution (discharge capacity) on the plating or alloying (charging capacity) that forms a solid solution during cell operation. Interestingly, the cell showed 100% Coulomb efficiency in the first cycle and maintained it throughout the entire 300 cycles. However, the cell overvoltage (Figures 12c-e) gradually increased with the cycles, likely due to an increase in the cell's internal resistance or degradation of the interface between the Li metal used as the counter electrode and the electrolyte. Nevertheless, the 100% Coulomb efficiency over 300 cycles indicates that the MCA pellet is very efficient in lithium cycling. The results presented here demonstrate that Li-containing FAM442 pellets, as lightweight current collectors, present an attractive combination of weight reduction, improved energy density, structural integrity, and dendrite suppression, positioning them as a promising solution for advanced LIBs and LMBs.

[0106] <Conclusion> Innovative MCA Design: This patent presents a novel method for creating multi-component alloy (MCA) systems with a body-centered cubic (bcc) solid solution phase, achieved through advanced computational studies. These MCAs are optimized for interfacial energy and enthalpy of mixing, ensuring excellent performance as dendrite-free anodes and current collectors, and thus can be used in lithium metal and lithium-ion batteries with anode-free configurations, where Li is LiCoO2, LiNiO2, LiNi 1-x Co x O2(0 <x<1)、およびLiNi 1-x-y Mn x Co yIt is directly supplied from a cathode such as O2(0<x+y<1), and the same applies to developing systems such as Li-S systems that use Li2S as a cathode. In the lithiated form, the MCA system can also be used as a dendrite-free anode and current collector for Li-sulfur, Li-S, and Li-O2 batteries.

[0107] Lightweight and efficient current collector: The MCA system developed in this patent presents a significant reduction in density, which is more than 50% lower than that of conventional copper current collectors. This makes it very attractive as a lightweight current collector replacement, contributing to the overall efficiency and energy density of the battery system.

[0108] Scalable synthesis process: MCA is synthesized using scalable and cost-effective methods including HEMM / HEMA. This process ensures the feasibility of large-scale production, making these materials suitable for industrial applications. Furthermore, the use of cold pressing (CP), cold isostatic pressing (CIP), and cold uniaxial pressing (CUP) at moderate temperatures of about 100 to 150°C ensures the formation of high-density pellets that can also be cold-rolled to form foils for direct use as current collectors in anode-free configurations replacing currently used copper current collectors in Li-ion batteries.

[0109] Solid solution formation with lithium: MCA is designed to allow lithium to form a solid solution by occupying void sites within the bcc phase. This unique interaction between lithium and MCA prevents dendrite formation and improves the safety and reliability of batteries.

[0110] Diversity of MCA compositions: Various MCA compositions including FAM145, FAM541, and FAM442 have been synthesized and evaluated. These compositions exhibit promising electrochemical performance in both coin cell and pouch cell configurations, highlighting their potential for use in advanced battery technologies.

[0111] Industrial Feasibility of FAM442: Among the tested compositions, FAM442 demonstrated particularly strong electrochemical performance in both coin cells and pouch cells, indicating suitability for battery applications in industrial and automotive technologies. Its stability and efficiency make it a viable candidate for integration into commercial battery products, while all compositions equally demonstrate promising use as dendrite-free anodes and current collectors.

[0112] Applications in anode-free configurations: MCA systems can be used in their pre-lithium-treated alloy state as anodes and current collectors, or as components in anode-free configurations with lithium-containing cathodes. This versatility expands potential applications in next-generation battery technology and presents new possibilities for high-performance, lightweight, and secure energy storage solutions.

Claims

1. A lithium-ion battery or a lithium metal battery, A current collector that does not include an anode, It is a multi-component alloy, (i) 40 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 20 atomic percent magnesium, or (ii) 10 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 50 atomic percent magnesium, or (iii) 50 atomic percent iron, 40 atomic percent of aluminum or gallium, and A multi-component alloy containing 10 atomic percent magnesium, A cathode containing lithium, A current collector containing an electrolyte, but not containing an anode, A lithium-ion battery or lithium metal battery in which no dendrites are formed throughout the entire charging and discharging process of the battery.

2. The lithium-ion battery or lithium metal battery according to claim 1, wherein the electrolyte comprises a polymer gel.

3. The cathode is LiCoO ２ , LiNiO ２ , and LiNi ０．８ Co ０．１ Mn ０．１ O ２ , and LiNi １－ｘ Co ｘ O ２ (0 < x < 1), and LiNi １－ｘ－ｙ Mn ｘ Co ｙ O ２ (0 < x + y < 1), wherein the cathode is selected from the group consisting of the above, and the lithium ion battery or lithium metal battery according to claim 1.

4. The lithium-ion battery or lithium metal battery according to claim 1, wherein the multi-component alloy includes a body-centered cubic structure that is maintained throughout the entire charging and discharging process of the battery.

5. The lithium-ion battery or lithium metal battery according to claim 1, wherein the multi-component alloy exhibits an optimal interfacial energy for alloying with lithium.

6. A lithium-ion battery or a lithium metal battery, A Li-containing anode comprising a multi-component alloy in solid solution form, wherein the multi-component alloy is It is a multi-component alloy, (i) 40 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 20 atomic percent magnesium, or (ii) 10 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 50 atomic percent magnesium, or (iii) 50 atomic percent iron, 40 atomic percent of aluminum or gallium, and A multi-component alloy containing 10 atomic percent magnesium, Cathode and, An electrolyte and a Li-containing anode, A lithium-ion battery or lithium-metal battery in which no dendrites are formed throughout the entire charging and discharging process of the battery.

7. A method for preparing a current collector that does not include an anode, The preparation of a multi-component alloy, To obtain iron, aluminum or gallium, and magnesium in their dry forms, The dry forms of iron, aluminum, or gallium, and magnesium are described below. (i) 40 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 20 atomic percent magnesium, or (ii) 10 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 50 atomic percent magnesium, or (iii) 50 atomic percent iron, 40 atomic percent of aluminum or gallium, and Blending or mixing based on an alloy composition selected from 10 atomic percent magnesium, The aforementioned alloy composition is subjected to high-energy pulverization treatment to form a high-energy pulverized composition, The process includes forming a current collector containing the high-energy pulverization composition, and preparing a multi-component alloy. A method in which no dendrites are formed in the lithium-ion battery or lithium-metal battery throughout the entire charging and discharging process of the battery.

8. The method according to claim 7, further comprising forming pellets containing the high-energy pulverized composition before forming the current collector.

9. The method according to claim 7, wherein the pellet formation includes cold pressurization, cold isotropic pressurization, and cold uniaxial pressurization at a moderate temperature of about 100 to 150°C.

10. The method according to claim 8, further comprising cold-rolling the pellets to form foil for direct use as a current collector.

11. A method for preparing a Li-containing anode, The preparation of a multi-component alloy, To obtain iron, aluminum or gallium, and magnesium in their dry forms, The dry forms of iron, aluminum, or gallium, and magnesium are described below. (i) 40 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 20 atomic percent magnesium, or (ii) 10 atomic percent of iron, 40 atomic percent of aluminum or gallium, and 50 atomic percent magnesium, or (iii) 50 atomic percent iron, 40 atomic percent of aluminum or gallium, and Blending or mixing based on an alloy composition selected from 10 atomic percent magnesium, The aforementioned alloy composition is subjected to high-energy pulverization treatment to form a high-energy pulverized composition, The preparation of a multi-component alloy includes applying or depositing the high-energy pulverization composition onto a current collector to form a solid solution, A method in which no dendrites are formed in the lithium-ion battery or lithium-metal battery throughout the entire charging and discharging process of the battery.

12. Forming pellets containing the aforementioned high-energy pulverized composition, Forming a slurry containing the aforementioned pellets, The method according to claim 11, further comprising applying the slurry to a current collector to form a solid solution.

13. The method according to claim 11, wherein the dried form is a powder.

14. The method according to claim 11, wherein the ratio of the powder to the mill ball is constant at 1:

1.

15. The method according to claim 11, wherein the solid solution includes a body-centered cubic crystal structure.

16. The method according to claim 11, wherein forming the slurry includes adding polyvinylidene fluoride as a binder.

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