Three-dimensional gradient lithium-loving-lithium-phobic composite structure current collector and manufacturing method thereof
By constructing a three-dimensional gradient lithium-loving-lithiophobic composite structure on a commercial current collector, the problem of lithium dendrite growth was solved, achieving uniform lithium metal deposition and high cycle stability and safety of the battery.
Patent Information
- Application Number
- CN202511548556.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-28
- Publication Date
- 2026-01-30
AI Technical Summary
Existing technologies make it difficult to manage the entire process of lithium deposition behavior in lithium metal anode current collectors, leading to uncontrollable growth of lithium dendrites, which affects battery safety and cycle life.
A three-dimensional gradient lithium-friendly-lithiophobic composite structure was constructed on an ultrathin commercial current collector. Through the synergistic design of a porous metal framework, a lithium-friendly control layer and a lithium-phobic layer, lithium metal was guided to preferentially nucleate inside the current collector and undergo bottom-up filling deposition. Combined with the lithium-phobic layer, lithium dendrite growth was blocked.
Uniform lithium metal deposition and dendrite suppression were achieved without increasing the thickness and weight of the current collector, thereby improving the cycle stability and safety of the battery.
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Figure CN121439802A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of secondary batteries, in particular to a three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector and a manufacturing method thereof. BACKGROUND
[0002] Lithium metal anode is considered as an ideal anode material for the next generation of high energy density batteries due to its high theoretical specific capacity and low electrochemical potential, especially in the anode-free lithium metal battery architecture, which directly uses the current collector as the anode carrier to improve the energy density of the battery. However, the deposition barrier of lithium ions on the traditional current collector such as pure copper foil is large, which leads to uneven deposition and uncontrollable growth of lithium dendrites. Lithium dendrites not only can pierce the separator to cause short circuit of the battery, which brings safety hazards, but also can form "dead lithium" by repeated fracture, which continuously consumes electrolyte and reduces the coulombic efficiency and cycle life of the battery.
[0003] To address this challenge, existing technologies focus on constructing a lithiumophilic layer on a three-dimensional porous foam metal (such as foam copper, foam nickel) substrate, or modifying a two-dimensional copper foil with a single lithiumophilic material (such as Ag, Sn). Three-dimensional current collectors can effectively reduce the local current density and provide space for the volume change of the electrode during the cycle, thereby inhibiting dendrites to some extent and improving cycle stability. Existing modification strategies focus on single lithiumophilic treatment or simple lithiumophobic coating, and lack the ability to manage the whole process of lithium metal from nucleation to growth in multiple stages.
[0004] Although the lithiumophilic layer can reduce the nucleation overpotential and promote uniform initial nucleation of lithium, it cannot prevent lithium from preferentially growing towards the electrolyte direction (i.e. above or outside the current collector) during subsequent cycles, and eventually still may form dendrites. A single lithiumophobic layer can guide the transport of lithium ions inside the current collector, but may result in too high lithium deposition overpotential, or fail due to its insufficient density, and cannot effectively block the growth of the tip of the dendrites. Recent studies have begun to focus on guiding the deposition behavior of lithium through structural design. However, these schemes still face challenges in how to successfully integrate such gradient structures into ultra-thin, commercial two-dimensional current collectors, while controlling composition and function, and ensuring the scalability and cost controllability of the preparation process. Therefore, it is necessary to optimize the structure of the current collector and its manufacturing method, so that it can realize functional gradient on ultra-thin commercial current collectors, give it the dual functions of guiding uniform lithium deposition and inhibiting dendrites without increasing the thickness and weight of the current collector, and achieve precise and whole-process management of the deposition behavior of lithium metal. SUMMARY
[0005] The application aims to provide a three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector and a manufacturing method thereof. The core purpose is to guide lithium metal to preferentially nucleate inside the current collector and realize bottom-up filling deposition by constructing a gradient structure with decreasing lithiumophilicity from inside to outside and covering a lithiumophic layer on an ultra-thin commercial current collector, thereby simultaneously solving the problems of uneven lithium deposition and dendrite growth without significantly increasing the thickness and weight. The purpose of the application is achieved by the following technical scheme. The three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector comprises a porous metal skeleton, a lithiumophilic-lithiophobic regulation layer, and a lithiumophic layer. The porous metal skeleton has skeleton pores. The lithiumophilic-lithiophobic regulation layer is in-situ grown on the surface in the porous metal skeleton. The lithiumophic layer is formed on the outer layer of the porous metal skeleton. The material of the lithiumophilic-lithiophobic regulation layer is an alloy composed of a lithiumophilic metal and a lithiumophic metal, the material of the lithiumophilic metal is silver or tin, and the content of the lithiumophilic metal gradually decreases from inside to outside.
[0006] In one embodiment, the material of the porous metal skeleton is selected from one or more of the following materials: copper, aluminum, nickel, or zinc.
[0007] In one embodiment, the material of the lithiumophic layer is selected from one or more of the following materials: graphene, fluorocarbon material, amorphous carbon layer.
[0008] In one embodiment, the volume of the lithiumophilic-lithiophobic regulation layer accounts for less than 50% of the volume of the skeleton pores.
[0009] In one embodiment, the pore size of the skeleton pores gradually decreases from inside to outside after the formation of the lithiumophilic-lithiophobic regulation layer.
[0010] In one embodiment, the copper content in the lithiumophilic-lithiophobic regulation layer gradually increases from inside to outside.
[0011] In one embodiment, the pore size of the skeleton pores is in the range of 1-200 mu m, and the thickness of the lithiumophilic-lithiophobic regulation layer is in the range of 20-300 nm.
[0012] The application also provides a manufacturing method of a three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector, comprising: Providing a current collector comprising a porous metal skeleton, the porous metal skeleton having skeleton pores. The surface in the skeleton pores of the porous metal skeleton is deposited with a wettability regulation layer by electrochemical deposition, wherein the material of the wettability regulation layer is an alloy composed of a lithiumophilic metal and a lithiumophobe metal, and the content of the lithiumophilic metal in the wettability regulation layer gradually decreases from inside to outside by controlling the solution concentration and the electrodeposition potential during the deposition process. After the deposition of the wettability regulation layer is completed, a lithiumophobe layer is formed on the outer layer of the porous metal skeleton by chemical vapor deposition.
[0013] In one of the embodiments, before the deposition of the wettability regulation layer, the current collector is also treated by anodic oxidation and hydrogen reduction.
[0014] In one of the embodiments, the step of forming the lithiumophobe layer specifically involves introducing a carbon source gas, and the lithiumophobe layer formed is a graphene layer, a fluorocarbon material layer or an amorphous carbon layer.
[0015] Compared with the prior art, the present application has the following beneficial effects: By constructing a three-dimensional porous metal skeleton, a high specific surface area is provided, which helps to reduce the local current density. The wettability regulation layer grown in situ on the surface in the skeleton pores has a lithiumophilic metal (such as silver, tin) content that gradually decreases from inside to outside, forming a corresponding lithiumophilic gradient, which can actively guide the lithium metal to preferentially nucleate at the current collector / electrode interface (i.e. the bottom or inside of the pores), and induce the lithium metal to fill and deposit from bottom to top. This helps to avoid direct contact between the lithium deposition front and the electrolyte, thereby reducing the formation and growth of lithium dendrites. In addition, the lithiumophobe layer (such as graphene, fluorocarbon material) covering the outer layer of the porous metal skeleton can further regulate the flow of lithium ions.
[0016] The wettability regulation layer and the porous metal skeleton are combined by in-situ growth, which helps to ensure the interfacial adhesion. At the same time, the lithiumophobe layer on the outer layer (such as a graphene layer or a fluorocarbon material layer generated by chemical vapor deposition) has a dense structure, which can effectively reduce the side reactions between the electrode and the electrolyte and stabilize the interface. In particular, the lithiumophobe layer related to fluorocarbon material helps to form a stable solid-state electrolyte interface film rich in lithium fluoride, which has good lithium ion conductivity and electronic insulation, and can further inhibit dendrite growth and improve interface stability. The synergistic effect helps to reduce the active lithium loss and the increase of battery impedance during the cycle process, thereby improving the coulombic efficiency and cycle life of the battery.
[0017] The technical solution of the present application can be based on the functional modification of an ultrathin commercial copper foil (such as a nanoporous copper skeleton obtained by anodic oxidation and reduction treatment), and the wettability regulation layer and the lithiumophobe layer are both thin layer structures. This makes the current collector have the dual functions of guiding lithium deposition and inhibiting dendrites while the overall thickness and weight do not increase significantly, which is conducive to maintaining the high energy density of the battery, especially the lithium metal battery without negative electrode.
[0018] In summary, the present application realizes the guidance and spatial limitation of lithium metal deposition behavior by constructing a gradient of increasing lithiumophilicity from inside to outside on the porous metal framework, combined with a lithiumophobe layer on the outer surface, thereby simultaneously improving the cycle stability and safety of the battery on the ultra-thin current collector. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a flowchart of the manufacturing method of the three-dimensional gradient lithiumophilic-lithiophobe composite structure current collector in an embodiment of the present application. DETAILED DESCRIPTION
[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the sake of description, only the parts related to the present application are shown in the drawings, not all the structures. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.
[0021] The terms "comprising" and "having" and any variations thereof in the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to these processes, methods, products or devices.
[0022] Reference to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0023] In view of the technical problem of how to realize the whole process management of lithium metal deposition on ultra-thin commercial copper foil without significantly increasing the thickness and weight, the solution of the present application is to: by constructing a composition continuously changing lithiophilic and lithophobic regulation layer in a porous metal framework, and setting a lithium-averse barrier on the outer layer, a composite structure with spatial gradient function is formed. The structure is designed to actively guide the lithium metal to preferentially nucleate at the current collector / electrode interface, and realize the filling type deposition mode from bottom to top. The composition and structure of the three-dimensional gradient lithiophilic-lithophobic composite structure current collector, the functional relationship of each layer, and the manufacturing method of the structure through electrochemical deposition and chemical vapor deposition process steps will be described in detail below in conjunction with specific embodiments. Please refer to Figure 1 The manufacturing method of the three-dimensional gradient lithiophilic-lithophobic composite structure current collector of the present application comprises: providing a current collector comprising a porous metal framework, the porous metal framework having a framework pore, depositing a lithiophilic and lithophobic regulation layer on the surface in the framework pore of the porous metal framework by electrochemical deposition, wherein the material of the lithiophilic and lithophobic regulation layer is an alloy composed of a lithophilic metal and a lithium-averse metal, and during the deposition process, the concentration of the solution and the electrodeposition potential are controlled to gradually reduce the content ratio of the lithophilic metal in the lithiophilic and lithophobic regulation layer from inside to outside. After the deposition of the lithiophilic and lithophobic regulation layer is completed, a lithium-averse layer is formed on the outer layer of the porous metal framework by chemical vapor deposition.
[0024] The manufacturing method of the three-dimensional gradient lithiophilic-lithophobic composite structure current collector of the present application can construct a composite structure with composition gradient and functional division on an ultra-thin commercial current collector through a series of coordinated process steps to manage the deposition behavior of lithium metal. The manufacturing method can directly use a current collector with a porous metal framework having a framework pore. A specific preparation path is: using a commercial copper foil as a raw material, first forming a copper oxide template on the surface by anodic oxidation method, and then reducing the copper oxide in a diluted hydrogen atmosphere by heat treatment, thereby obtaining a copper framework with a nanoporous structure. During this process, the morphology of the porous structure, such as the diameter and length of the nanowires, can be controlled by adjusting the temperature and time of the oxidation stage. The porous metal framework mainly plays two roles: first, its three-dimensional continuous porous structure increases the specific surface area of the current collector, which helps to reduce the local current density during the cycle process, and lays the foundation for uniform lithium deposition; second, these interconnected framework pores provide sufficient accommodation space for subsequent lithium deposition, which can adapt to the volume change of the electrode during charging and discharging.
[0025] After obtaining a porous metal framework, an affinity / reactivity control layer is deposited in situ on the inner surface of the framework pores using electrochemical deposition. This control layer is an alloy composed of a lithiophilic metal (such as silver or tin) and a lithiophore metal (such as copper). By precisely controlling parameters such as the concentration of metal ions in the electroplating solution and the deposition potential, a gradient distribution of the lithiophilic metal (Ag, Sn) content in the alloy can be achieved, continuously decreasing from the bottom of the pores (current collector / electrode interface) to the top of the pores (near the electrolyte), thus controlling the spatial gradient change of the lithiophilicity of the control layer. The region with high lithiophilicity is located deep within the pores, which can reduce the overpotential for lithium nucleation and guide lithium metal to preferentially nucleate there. As the lithiophilicity gradually weakens outward, the driving force for lithium deposition also decreases, thereby synergistically guiding lithium metal to undergo "filling" deposition from the inside out and from the bottom up. This deposition mode confines the lithium deposition front inside the current collector, avoiding direct contact with the electrolyte and physically restricting the unchecked growth of lithium dendrites towards the electrolyte.
[0026] After depositing the gradient affinity / reluctance control layer, the manufacturing method further utilizes chemical vapor deposition (CVD) to form a lithium-phobic layer on the outer layer of the porous metal framework (i.e., the surface closest to the electrolyte). For example, graphene can be grown on the framework surface by introducing carbon source gases such as methane, or fluorocarbon materials or amorphous carbon layers can be formed. This further prevents lithium metal from growing outwards (towards the electrolyte), working synergistically with the internal lithium-philic gradient to confine lithium deposition within the three-dimensional porous framework. Secondly, materials like graphene possess high chemical stability and density, reducing side reactions between the current collector surface and the electrolyte, thus contributing to the formation of a stable electrode / electrolyte interface. In particular, if the lithium-phobic layer uses fluorocarbon materials, it also helps form a LiF-rich solid electrolyte interphase (SEI) film during the initial cycling phase. This SEI film has good lithium-ion conductivity, further promoting uniform lithium deposition and improving interface stability.
[0027] The manufacturing method described in this application organically combines processes such as anodic oxidation-hydrogen reduction, electrochemical deposition, and chemical vapor deposition to construct a three-dimensional gradient lithium-affinity-lithium-repellent composite structure on an ultrathin commercial current collector. These process steps are interconnected, and the resulting composite current collector, through the synergistic effect of a porous framework, a gradient lithium-affinity / lithium-repellent control layer, and an outer lithium-repellent layer, provides a solution to overcome bottlenecks in lithium metal anode applications (such as dendrite growth and interface instability).
[0028] In the preparation process of the three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector, the anodic oxidation and subsequent hydrogen reduction treatment of the commercial copper foil current collector before the deposition of the lithiumophilic-lithiophobic regulation layer. The pretreatment step specifically involves placing the copper foil as an anode in an alkaline solution (for example, a potassium hydroxide solution with a concentration of 4-6 mol / L) and applying a specific current density (for example, 8-12 mA / cm²) for anodic oxidation. This process can generate a layer of copper hydroxide nanowire or nanosheet array structure in situ on the surface of the copper foil. Subsequently, heat treatment is carried out in a hydrogen atmosphere to reduce the copper hydroxide nanostructure to a nanoporous copper framework with three-dimensional interconnected pores.
[0029] The nanoporous copper framework obtained by anodic oxidation and hydrogen reduction increases the specific surface area of the current collector, providing more active sites for the subsequent deposition of lithium metal and providing space to accommodate the volume change of the electrode during the cycle. The three-dimensional nanoporous structure is the physical basis for the in-situ growth and attachment of the subsequent gradient lithiumophilic-lithiophobic regulation layer. The copper framework surface with fine microstructure and high chemical activity is more conducive to the uniform nucleation and combination of functional materials. In addition, since the porous structure is formed directly by treating ultra-thin commercial copper foil, it can ensure that the overall thickness of the current collector does not increase significantly while introducing a three-dimensional structure.
[0030] After the construction of the gradient lithiumophilic-lithiophobic regulation layer is completed, the present application forms a lithiumophobie layer on the outer layer of the porous metal framework by chemical vapor deposition (CVD) technology. This step specifically involves introducing carbon source gas, such as methane (CH4), acetylene (C2H2), or fluorine-containing carbon source gas (such as tetrafluoromethane (CF4)), to grow graphene, amorphous carbon layer or fluorocarbon material layer on the surface of the framework in situ.
[0031] When the lithiumophobie layer is graphene or amorphous carbon layer generated by cracking of carbon source gas such as methane, it can form a dense film covering the surface of the three-dimensional porous framework. This film has a lower lithium metal nucleation overpotential characteristic, which can reduce the deposition driving force of lithium ions on the outer surface of the current collector, thereby guiding lithium ions to continue to migrate and deposit in the pore interior, i.e. the area with higher lithiumophilic gradient regulation layer. At the same time, as an effective physical barrier layer, the dense layer can inhibit the outward growth of the deposited lithium metal to form dendrites and reduce the direct contact area between the electrode and the electrolyte, which helps to reduce the interface side reaction.
[0032] The three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector formed by the above method comprises a porous metal skeleton, a lithiumophilic-lithiophobic regulation layer and a lithiumophic layer, the porous metal skeleton has skeleton pores, the lithiumophilic-lithiophobic regulation layer is in-situ grown on the surface in the porous metal skeleton, and the lithiumophic layer is formed on the outer layer of the porous metal skeleton, wherein the material of the lithiumophilic-lithiophobic regulation layer is an alloy composed of a lithiumophilic metal and a lithiumophic metal, the material of the lithiumophilic metal is silver or tin, and the content ratio of the lithiumophilic metal gradually decreases from inside to outside.
[0033] The porous metal skeleton constitutes the support body and the basic three-dimensional structure of the entire composite current collector. Its core role is to provide sufficient lithium deposition space and a high specific surface area conductive network. Specifically, the skeleton has interconnected skeleton pores, for example, a nanoporous copper structure obtained by anodizing and hydrogen reduction of a commercial copper foil, which provides more nucleation sites for lithium deposition and can adapt to the volume change of the electrode during charging and discharging. In addition, the ultra-thin porous skeleton constructed on the basis of commercial metal foils such as copper, aluminum, nickel or zinc ensures that the current collector does not significantly increase in overall thickness and weight while introducing a three-dimensional structure, which is crucial for maintaining the high volumetric energy density of the battery.
[0034] The lithiumophilic-lithiophobic regulation layer is in-situ grown on the inner surface of the pores of the porous metal skeleton, and the material thereof is an alloy composed of a lithiumophilic metal (such as silver or tin) and a lithiumophic metal (such as copper). The innovation of this layer lies in the continuous gradient design of its composition, that is, the content ratio of the lithiumophilic metal (Ag, Sn) gradually decreases from the inside of the skeleton pores (close to the body of the current collector) to the outside (close to the direction of the electrolyte), forming a corresponding spatial gradient of lithiumophilicity. The high lithiumophilic region located in the deep part of the pores can reduce the nucleation overpotential of lithium, guiding the lithium metal to preferentially nucleate there; and the gradually weakened lithiumophilicity outwardly cooperatively induces the "filling type" deposition of lithium metal from inside to outside and from bottom to top, so that the lithium deposition front is limited inside the current collector, avoiding direct contact with the electrolyte, thereby limiting the growth of lithium dendrites in the direction of the electrolyte from the physical space and chemical driving force.
[0035] The lithiumophic layer is formed on the outer layer of the porous metal skeleton, that is, the surface closest to the electrolyte. The layer can be composed of graphene, fluorocarbon material or amorphous carbon layer, etc., formed by, for example, chemical vapor deposition of methane or fluorocarbon-containing gas, which has a relatively low deposition driving force for lithium, and can further block the preferential growth of lithium metal outward (in the direction of the electrolyte), and secondly, such a dense layer as graphene or fluorocarbon material can reduce the side reactions between the surface of the current collector and the electrolyte.
[0036] In the construction of the three-dimensional gradient lithiumophilic-lithiphobic composite structure current collector, the volume ratio of the lithiumophilic-lithiphobic regulating layer to the volume of the skeleton pores is less than 50%. This limitation ensures that the composite current collector maintains the advantages of its three-dimensional porous structure during lithium metal deposition while introducing the functional gradient layer. First, the volume ratio of the lithiumophilic-lithiphobic regulating layer is less than 50%, and more than half of the original space in the skeleton pores is retained, providing the necessary accommodation space for lithium metal deposition. If the functional layer completely fills or occupies too much pore space, it will weaken the core role of the porous skeleton in reducing local current density through its high specific surface area and providing buffer for electrode volume expansion. Sufficient reserved space can accommodate the large volume change of the electrode during charging and discharging, reducing the stress generated by volume fluctuation, thereby helping to maintain the integrity of the electrode structure and preventing active material from falling off or the current collector structure from collapsing. Controlling the volume ratio to be below 50% can provide sufficient nucleation sites and chemical driving force on the inner surface of the skeleton while ensuring that there is a continuous and unobstructed ion transport channel inside the pores, allowing lithium ions to reach deposition sites throughout the pores, ensuring smooth deposition.
[0037] In the construction of the three-dimensional gradient lithiumophilic-lithiphobic composite structure current collector, the skeleton pores after forming the lithiumophilic-lithiphobic regulating layer exhibit a gradient distribution of pore size gradually decreasing from the inside to the outside. This gradient pore structure is mainly formed through the following methods: first, by subjecting the copper foil to anodic oxidation and hydrogen reduction treatment, a three-dimensional porous copper skeleton with initial uniform pores is generated in situ. Subsequently, during the construction of the lithiumophilic-lithiphobic regulating layer using electrochemical deposition technology, by controlling the deposition potential and the concentration of metal ions in the solution, the content of lithiumophilic metal (such as silver, tin) in the alloy decreases gradually from the inside of the skeleton pores (close to the current collector body) to the outside (close to the electrolyte direction). Since deposition occurs along the inner surface of the pores, the effective flow-through pore size decreases more significantly at the inside of the pores with a higher content of lithiumophilic metal, while at the outside of the pores with a lower content of lithiumophilic metal, the deposition layer is thinner and the pore size decreases relatively less. Ultimately, this non-uniform deposition associated with the composition gradient leads to the formation of a pore size gradient in the modified skeleton pores, gradually decreasing from the inside to the outside.
[0038] The gradually decreasing pore size distribution from inside to outside forms a conical channel in physical space. When combined with the internal high lithiophilicity and external low lithiophilicity component gradient, a region with stronger thermodynamic driving force and lower nucleation barrier can be created inside the pores, thereby preferentially guiding lithium metal nucleation at the bottom of the pores. During the subsequent growth stage of lithium deposition, the gradually expanding pore space provides sufficient accommodation volume for lithium deposition, helping to adapt to the volume change of the electrode during the cycle process and reduce the stress generated by volume expansion. More importantly, this structural design allows the lithium metal deposition front to gradually relax the spatial restrictions during the upward (outward) growth process, helping to maintain a relatively uniform current density distribution and avoid the lithium deposition front from losing stability due to sudden changes or restrictions in space, thereby cooperating with the lithium-poor layer on the outside to effectively constrain the lithium deposition behavior inside the three-dimensional porous framework.
[0039] In the construction of the three-dimensional gradient lithiophilic-lithiophobic composite structure current collector, the copper content in the lithiophilic-lithiophobic regulation layer gradually increases from inside to outside, and this component gradient distribution is realized by electrochemical deposition technology. Specifically, in an electroplating solution containing silver ions, tin ions and copper ions, by program-controlled deposition potential or the relative concentration of each metal ion in the electrolyte, an alloy layer rich in lithiophilic metals such as silver or tin is formed on the inner surface of the porous framework pores at the initial stage of deposition; as the deposition continues, the copper content in the subsequent deposition layer is gradually increased by adjusting the electrical parameters, and finally the copper content in the entire lithiophilic-lithiophobic regulation layer presents a continuous increasing gradient distribution from the inside to the outside of the pores.
[0040] This component gradient design directly leads to the spatial gradual change of the lithiophilicity of the regulation layer. The region with a higher content of lithiophilic metals (such as Ag, Sn) on the inside of the pores has a stronger tendency to alloy with lithium metal, which can effectively reduce the nucleation overpotential of lithium, thereby guiding lithium metal to preferentially nucleate in this region. As the position moves outward, the gradual increase in copper content makes the deposition driving force of lithium on this surface relatively weak, which cooperatively induces the lithium metal deposition front to expand from inside to outside and from bottom to top. The "filling type" deposition mode, benefiting from the gradual weakening of the lithiophilicity driving force from inside to outside, makes the lithium deposition tend to continue in the thermodynamically more favorable bottom and inside of the pores until the pore space is filled, thereby avoiding the lithium deposition front from directly contacting the electrolyte at the initial stage of growth, which provides key thermodynamic and kinetic conditions for inhibiting the formation and growth of dendrites from the nucleation stage.
[0041] In the construction of the three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector, the control of the pore size of the porous metal framework and the thickness of the lithiumophilic-lithiophobic regulation layer is to set the pore size of the framework pores in the range of 1 μm to 200 μm, and control the thickness of the lithiumophilic-lithiophobic regulation layer to be between 20 nm to 300 nm. The pore size in the above range can provide a higher specific surface area for the current collector, which helps to reduce the local current density during the battery cycle process, and creates conditions for uniform deposition of lithium. Providing sufficient accommodation space for lithium metal deposition can effectively adapt to the larger volume change of the electrode during charging and discharging, reduce the stress generated by volume expansion, and thus help to maintain the integrity of the electrode structure. In addition, the interconnected pore structure at this scale can ensure effective infiltration of the electrolyte and smooth transport of lithium ions, reducing ion migration resistance.
[0042] At the same time, the thickness of the lithiumophilic-lithiophobic regulation layer is controlled to be between 20 nm and 300 nm to balance the function and structural stability. The lithiumophilic-lithiophobic regulation layer is grown in situ on the inner surface of the framework pores by electrochemical deposition technology, and its composition has a gradient change. It ensures that the functional layer can completely and continuously cover the surface of the framework, providing sufficient lithiumophilic driving force that decreases from inside to outside to effectively guide the lithium metal to preferentially nucleate at the bottom of the pores and fill from bottom to top. The thickness of nanoscale can avoid excessive occupation of the internal space of the framework pores. As mentioned in the previous technical features, the volume ratio of the lithiumophilic-lithiophobic regulation layer to the volume of the framework pores is less than 50%, thereby ensuring that there is sufficient volume in the pores for accommodating lithium metal.
[0043] As described above, the present application provides a three-dimensional gradient lithiumophilic-lithiophobic composite structure current collector and a manufacturing method thereof. The current collector includes a porous metal framework having framework pores, a lithiumophilic-lithiophobic regulation layer grown in situ on the inner surface of the framework pores, and a lithiumophobie layer formed on the outer layer of the porous metal framework. The manufacturing method includes: preparing a porous metal framework by anodizing and hydrogen reduction treatment of a commercial metal foil; using electrochemical deposition technology to construct a gradient lithiumophilic-lithiophobic regulation layer with gradually decreasing lithiumophilic metal content from inside to outside on the inner surface of the framework pores by controlling the deposition parameters; and then forming a lithiumophobie layer of graphene, fluorocarbon material or amorphous carbon layer on the outer layer of the framework by chemical vapor deposition technology.
[0044] The composite structure provides high specific surface area and lithium accommodation space through the porous framework, guides the lithium metal to preferentially nucleate at the current collector / electrode interface and achieve bottom-up filling deposition through the composition gradient lithiumophilic-lithiophobic regulation layer, and inhibits the outward growth of lithium dendrites through the outer lithiumophobie layer as a physical barrier. The synergistic effect of each structure layer effectively manages the lithium metal deposition behavior without significantly increasing the thickness and weight of the current collector, which helps to improve the cycle stability and safety of lithium metal batteries.
[0045] The above merely describes one specific implementation of the present application, and any improvement made on the basis of the concept of the present application is deemed to be within the protection scope of the present application.
Claims
1. A three-dimensional gradient lithiophilic-lithophobic composite structure current collector, characterized in that, The porous metal framework, the affinity and repellency regulation layer, and the lithium-repellent layer are included. The porous metal framework has framework pores. The affinity and repellency regulation layer is formed in-situ on the surface in the porous metal framework. The lithium-repellent layer is formed on the outer layer of the porous metal framework. The material of the affinity and repellency regulation layer is an alloy of a lithiumophilic metal and a lithiumophobe, and the lithiumophilic metal is silver or tin.
2. The three-dimensional gradient lithiophilic-lithophobic composite structure current collector of claim 1, wherein, The material of the porous metal framework is selected from one or more of copper, aluminum, nickel, or zinc.
3. The three-dimensional gradient lithiophilic-lithophobic composite structured current collector of claim 1, wherein, The material of the lithium-repellent layer is selected from one or more of graphene, fluorocarbon material, or amorphous carbon layer.
4. The three-dimensional gradient lithiophilic-lithophobic composite structure current collector of claim 1, wherein, The volume of the affinity and repellency regulation layer accounts for less than 50% of the volume of the framework pores.
5. The three-dimensional gradient lithiophilic-lithophobic composite structure current collector of claim 4, wherein, The pore size of the framework pores gradually decreases from the inside to the outside after the formation of the affinity and repellency regulation layer.
6. The three-dimensional gradient lithiophilic-lithophobic composite structure current collector of claim 1, wherein, The copper content of the affinity and repellency regulation layer gradually increases from the inside to the outside.
7. The three-dimensional gradient lithiophilic-lithophobic composite structure current collector of claim 1, wherein, The pore size of the framework pores is in the range of 1 μm to 200 μm, and the thickness of the affinity and repellency regulation layer is in the range of 20 nm to 300 nm.
8. A method of manufacturing a three-dimensional gradient lithiophilic-lithophobic composite structure current collector, characterized by, The method comprises the following steps: A current collector including a porous metal framework having framework pores is provided. An affinity and repellency regulation layer is deposited on the surface in the framework pores of the porous metal framework by electrochemical deposition, wherein the material of the affinity and repellency regulation layer is an alloy of a lithiumophilic metal and a lithiumophobe, and the lithiumophilic metal content of the affinity and repellency regulation layer gradually decreases from the inside to the outside by controlling the solution concentration and the electrodeposition potential during the deposition process. After the deposition of the affinity and repellency regulation layer, a lithium-repellent layer is formed on the outer layer of the porous metal framework by chemical vapor deposition.
9. The method of manufacturing a three-dimensional gradient lithiophilic-lithophobic composite structured current collector according to claim 8, wherein Before the deposition of the affinity and repellency regulation layer, the current collector is treated by anode oxidation and hydrogen reduction.
10. The method of manufacturing a three-dimensional gradient lithiophilic-lithophobic composite structured current collector according to claim 8, wherein The lithium-repellent layer is formed by introducing a carbon source gas, and the lithium-repellent layer is a graphene layer, a fluorocarbon material layer, or an amorphous carbon layer.