Preloaded protected anode, battery and method of manufacture

Abstract

The present disclosure relates to a method of manufacturing an electrode (1n) comprising a current collector element (10) and a coating of a solid or semi-solid electrolyte (20), and a corresponding electrode portion. The method comprises depositing (300) an amount of an anode metal composition as a layer between the current collector element and a solid electrolyte covering the current collector element by an electroplating process involving directional transfer of anode metal ions through an electrolyte coating, where the solid electrolyte comprises: i) a first layer covering the current collector element, and i) a second layer covering the current collector element; the first layer at least initially comprises one or more additives that form a solid electrolyte interface layer by reaction with an electroplated anode metal composition, and ii) a second layer overlying the first layer, the second layer being resistant to inward penetration of a solvent included in the electroplating electrolyte (302). The present disclosure also relates to a battery comprising the electrode portion.

Description

[0001] Technical Field and Background Art

[0002] The present disclosure relates to electrode portions. In particular, such electrode portions include current collector elements and solid electrolyte coatings and are preloaded with a certain amount of anode metal composition. The present disclosure relates to batteries and methods of making electrode portions and batteries, such as lithium-based batteries, which include electrode portions with preloaded anode metal compositions.

[0003] Rechargeable lithium-ion batteries (LiBs) are the technology of choice for today's electric vehicles and renewable energy storage grids. To increase energy density, next-generation battery technology tends to move toward lithium metal anodes, with a potentially high specific capacity of 3860 mAh / g and a low redox potential of -3.04 V. These anodes can be combined with cathodes from a variety of chemical options, such as NMC (lithium nickel manganese cobalt oxide), LFP (lithium iron phosphate), LNMO (lithium nickel manganese oxide), sulfur or air.

[0004] During charging, Li ions travel from the cathode through the electrolyte to the anode to deposit as Li metal (Li 0 ). During discharge, they return to the cathode. However, during the plating / deplating cycles, the battery suffers from lithium loss due to adverse reactions of lithium with the electrolyte and / or due to the formation of porous or dendritic lithium deposits, which further presents an increasing risk of short circuits, thereby reducing the operational battery life and performance.

[0005] X. Zhang et al. (Acc. Chem. Res., 52, 3223-3232, 2019) describe a dendrite suppression strategy that can reduce Li loss during battery operation. However, Li loss, especially during the first plating cycle, is still disproportionately high.

[0006] Due to the high reactivity of lithium (like other alkali metals) to the environment, compensation for lost lithium is not obvious, which leads to the formation of an unfavorable resistant oxidation and / or nitridation surface layer, which has a negative impact on battery cycling and can negatively produce lithium deposition thereon and thus negatively affect battery life. In order to mitigate the growth of the oxidation surface layer, lithium can be treated in an Ar atmosphere. However, in practice, this does not satisfactorily reduce the growth rate and further significantly increases the operating costs.

[0007] WO2018190559A1 discloses electroplating Li onto a current collector from an electroplating solution comprising lithium nitrate and a metal nitrate.

[0008] CN112670450A discloses electroplating of lithium which is subsequently exposed to N2 gas and covered with a polymer / solid electrolyte in an attempt to reduce surface oxidation.

[0009] However, there remains a need for solutions that provide a method of providing lithium metal while mitigating the formation of an oxidized surface layer. Summary of the invention

[0010] The present disclosure seeks to overcome known limitations by simultaneously providing an electrode portion comprising a preloaded amount of an anode metal, such as lithium, which is covered by an electrolyte (typically a solid electrolyte layer) that shields the lithium from the environment.

[0011] The present disclosure provides effective, production-compatible surface protection of active anode metals such as Li.

[0012] At the same time, the currently disclosed solution improves subsequent anode metal plating, thereby mitigating porous / dendritic anode metal deposition, improving battery life and mitigating short circuit risks.

[0013] In particular, aspects of the present disclosure relate to methods of manufacturing an electrode portion that includes a current collector element and a solid or semi-solid layer coating of an electrolyte provided along a face of the current collector element.

[0014] The method disclosed herein advantageously provides an electrode portion of an anode metal composition having a preloaded amount. In addition, the method alleviates the degradation of the loaded anode metal, such as lithium metal, due to contact with the environment. The electrode portion can be advantageously used as a negative electrode portion in a battery application, such as a rechargeable lithium metal battery, whereby the electrolyte layer can be advantageously used as an ion conductive separator between the electrode portion and the counter electrode due to its solid or semi-solid properties. As will be described in detail below, the present disclosure also provides one or more improved battery performances regarding energy density, safety and / or lifespan.

[0015] The method of manufacturing an electrode portion includes electroplating a certain amount of an anode metal composition as a layer between a current collector element and an electrolyte covering the current collector element by electroplating, the anode metal composition generally including one or more alkali metals, such as lithium, sodium or potassium. The electroplating process involves the directional transfer of anode metal ions from an anode metal source such as an electroplating electrolyte toward a current collector element through an electrolyte coating, wherein at least before electroplating, a solid or at least semi-solid electrolyte layer includes one or more additives forming a solid electrolyte interface (SEI). The SEI is formed as a layer along the interface between the current collector element and the electrolyte by reacting with the electroplated anode metal. The SEI layer enables the anode metal ions to be transported toward the current collector element for further electroplating, while protecting the formed anode metal by hindering the penetration of active substances such as O2, N2 and / or CO2 from the environment (e.g., in a production environment such as a drying chamber), and the anode metal is generally highly active. Protecting the lower anode metal composition, the formation of degradation advantageously mitigates the degradation of the anode metal and the formation of materials (e.g., oxides and / or nitrides). Mitigating the degradation of the anode metal can advantageously increase the content of battery active materials that can be used within the battery context, such as increasing energy density. Mitigating the degradation of the anode metal can further improve electrode and / or battery performance and / or safety, such as in terms of improving electrode operation or plating uniformity during battery cycling.

[0016] The solid or semi-solid electrolyte is also advantageously resistant to in-penetration of solvents included in the electroplating electrolyte.Avoiding or at least mitigating in-penetration of solvents included in the electroplating electrolyte mitigates degradation / reaction of the electroplated anode metal with the solvent.

[0017] The electrolyte layer is typically formed as a stack of at least two different layers including a first layer that covers (usually in direct contact with) the current collector element and at least initially contains one or more functional additives that form the SEI layer. After electroplating, for example in a finished electrode portion, the amount of the additive is significantly reduced, optionally to zero or substantially zero. Covering the first layer is a second layer that is resistant to inward penetration of solvents included in the electroplating electrolyte. Providing a separate layer advantageously separates SEI formation from resisting inward penetration of solvents included in the electroplating electrolyte.

[0018] In a preferred embodiment, the current collector element is formed as a flexible foil, such as a metal foil or a metal-coated flexible carrier. Therefore, the electrode portion formed can advantageously be flexible. The method of manufacturing can advantageously be configured as a roll-to-roll process. Therefore, in a preferred embodiment, the method includes conveying the foil through a station configured for applying an electroplating process. Roll-to-roll manufacturing can advantageously enable batch manufacturing of electrode portions using a cost-effective continuous process that produces a roll of preloaded electrodes.

[0019] In another or additional preferred embodiment, the method includes controlling the amount of anode metal electroplated, for example by a controller according to a predefined target (e.g., anode metal layer thickness) by one or more of the following: controlling one or more plating parameters during electroplating (including the amplitude, duration and / or pulse shape of the plating current), and / or controlling the contact time of the substrate with the plating electrolyte (e.g., residence time in the plating bath).

[0020] The present disclosure also relates to an electrode part comprising a current collector element and an electrolyte layer arranged along a face of the current collector element.It will be appreciated that this part may be manufactured by a method according to the present disclosure.

[0021] The electrode portion manufactured, for example, by the disclosed process advantageously includes a preloaded amount of an anode metal composition. The anode metal composition is provided as a layer between a current collector element and an electrolyte coating. The solid electrolyte interface formed as a layer along the interface between the electrolyte and the anode metal composition layer mitigates anode metal degradation by the reaction of the anode metal with the environment. The current collector element and the formed electrode portion may advantageously be flexible. Because the anode metal is protected, the electrode portion may advantageously be stored as a roll, sheet, or as a block cut to size for further use, for example, in a battery.

[0022] In some embodiments, an electrode portion is provided, which is preferably obtainable by a method as disclosed herein, comprising a current collector element having an electrolyte coating disposed thereon, the electrolyte coating comprising: i) a first layer covering the current collector element, the first layer optionally comprising one or more functional additives, the functional additives forming a solid electrolyte interface layer by reaction when reacting with a plated anode metal composition provided by electroplating; and ii) a second layer covering the first layer, a preloaded amount of anode metal composition disposed as a layer between the current collector element and the electrolyte coating, and a solid electrolyte interface formed as a layer along the interface between the electrolyte coating and the layer of the anode metal composition, whereby the second layer is relatively more resistant than the first layer to electroplating solvents, for example, to the ingress of solvents from the electroplating solution.

[0023] Without wishing to be bound by theory, the inventors have found that being more resistant to plating solvents (e.g., the ingress of plating solvents) can be understood as being composed of a relatively more non-polar composition than the first layer. Alternatively or additionally, being more resistant to the ingress of solvents can be understood as having a relatively lower affinity (mutual solubility) for the plating solvents. The plating solvents can be understood to include, but are not limited to, being selected from: DOL (dioxolane), DME (dimethoxyethane), EC (ethylene carbonate) and DEC (diethyl carbonate), DMC (dimethyl carbonate), FEC (fluoroethylene carbonate), VC (ethylene carbonate), PC (propylene carbonate), HFE (hydrofluoroether), FEMC (trifluoroethyl methyl carbonate).

[0024] The present disclosure also relates to an electrode portion for use in an electroplating process according to any one of claims 1 to 9, the portion comprising: a current collector element and an electrolyte coating disposed thereon, wherein the electrode portion does not include a pre-deposited amount of anode metal, and wherein the electrolyte coating comprises: i) a first layer covering the current collector element, the first layer comprising one or more functional additives that form a solid electrolyte interface layer when reacting with a plated anode metal composition provided by electroplating; and ii) a second layer covering the first layer, the second layer being relatively more resistant to ingress of solvent from the electroplating solution than the first layer. Because the component does not yet include an amount of highly active anode metal, the component can be stored as a production component under mild conditions for later use (e.g., subsequent electroplating and / or battery assembly).

[0025] It will be appreciated that the electrode portion may advantageously be configured as a double-sided electrode portion, wherein respective ones of the electrolyte coatings are provided on opposite sides of a current collector element.

[0026] The present disclosure also relates to a battery comprising an electrode portion preloaded with a layer of an anode metal composition. The preloaded electrode portion is typically used as a so-called negative electrode of an anode metal battery, preferably a rechargeable anode metal battery, such as a secondary lithium metal battery (LMB). LBMs advantageously provide higher energy density than secondary batteries using composite anode compositions such as LiC or LiSi as electroactive compositions.

[0027] The battery generally includes a counter electrode portion (as a positive electrode) positioned across the electrode portion. In a preferred embodiment, the battery includes a cathode composition, which is provided along the face of the counter electrode portion along the face facing the preloaded electrode portion. Advantageously, a solid or semi-solid electrolyte can serve as a separator element separating the anode from the cathode composition. Alternatively, an electrolyte can be provided, such as impregnated with a liquid electrolyte. Alternatively or additionally, the battery can include an additional separator, such as a porous structure carrying an electrolyte, to improve the ion transport between the negative electrode portion and the positive electrode portion.

[0028] In a preferred embodiment, the battery is formed as a secondary lithium metal ion battery, wherein the preloaded layers of the cathode composition and the anode metal composition each include lithium. In addition to the lithium inventory provided by the cathode composition, the preloaded lithium metal layer advantageously provides a buffer amount of lithium. The preloaded lithium metal layer advantageously acts as a nucleation layer for subsequent anode metal plating (e.g., during initial and subsequent charging and operation of the battery), and acts as a buffer to replace the loss of lithium inventory during initial processing in lithium metal plating and deplating during battery operation. Compared to batteries without a preloaded metal layer (e.g., LMBs requiring initial internal plating processing), the preloaded anode metal layer advantageously increases the life of the battery (replacement loss), while improving battery safety by acting as a nucleation layer that improves the uniformity of the metal layer of subsequent electroplating.

[0029] In another embodiment, the electrode portion is used as a negative electrode in a secondary lithium sulfur battery (LiS) or a secondary lithium air battery (Li-air). In these embodiments, the layer of the anode metal composition can provide the lithium inventory of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other features, aspects, and advantages of the apparatus, systems, and methods of the present disclosure will become better understood from the following description, appended claims, and accompanying drawings, in which:

[0031] Figure 1A A schematic exploded side view of a battery including an electrode portion as disclosed herein is provided;

[0032] Figure 1B A schematic side view of an electrode portion as disclosed herein is provided;

[0033] Figure 2A schematically illustrates a method of manufacturing an electrode portion as disclosed herein;

[0034] Figure 2B Various aspects of manufacturing an electrode portion as disclosed herein are shown;

[0035] Figure 2C and Figure 2D A side view of a current collector element is provided;

[0036] Figure 3A Various aspects of manufacturing an electrode portion as disclosed herein are shown;

[0037] Figure 3B Various aspects related to the volume are shown;

[0038] Figure 3C A method of manufacturing a battery is schematically shown;

[0039] Figure 4A Provides detailed views of various aspects related to manufacturing electrode parts;

[0040] Figure 4B schematically illustrates an embodiment of a battery during a use condition;

[0041] Figure 4C schematically illustrates another embodiment of a battery during a use condition;

[0042] Figure 5A Further aspects of manufacturing an electrode portion as disclosed herein are shown; and

[0043] Figure 5B , Figure 5C and Figure 5D An exemplary electrode portion is shown prior to preloading the anode metal composition. DETAILED DESCRIPTION

[0044] The terms used to describe specific embodiments are not intended to limit the present invention. As used herein, the singular forms "a", "an", and "said" are also intended to include plural forms, unless the context clearly indicates otherwise. The term "and / or" includes any and all combinations of one or more of the associated listed items. It will be understood that the terms "include" and / or "comprise" specify the presence of the features, but do not exclude the presence or addition of one or more other features. It will be further understood that when a particular step of a method is referred to as being after another step, the step may be directly after the other step, or one or more intermediate steps may be performed before performing the particular step, unless otherwise stated. Similarly, it will be understood that when describing a connection between structures or components, unless otherwise stated, the connection may be established directly or through an intermediate structure or component.

[0045] As used herein, the term positive electrode or cathode and the term negative electrode or anode refer to the terms commonly used to identify the electrodes of a battery during discharge operation. In the discharge battery mode, the anode is the "negative electrode" to which the positive current flows from the cathode, which is the "positive electrode". During charging, these functions are reversed. Regardless of the charging mode, the electrochemical relationship can be characterized by the exchange of charge between the negative electrode material (anode composition) and the positive electrode material (cathode composition), the negative electrode material having a work function or redox potential lower than the work function or redox potential of the positive electrode material.

[0046] The term solid electrolyte should not be construed as being limited to being composed entirely of solid components. As described herein, it is contemplated, and even preferred, that the electrolyte includes non-solid components, such as liquid or waxy materials, such as ionic liquids, succinonitrile, and / or organic solvents. Thus, the term solid electrolyte explicitly includes semi-solid compositions, such as gels or solid compositions impregnated with liquids and / or waxes.

[0047] The present invention is described more fully below with reference to the accompanying drawings, in which embodiments of the invention are shown. In the accompanying drawings, the absolute and relative sizes of systems, components, layers and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic illustrations and / or cross-sectional illustrations of possible idealized embodiments and intermediate structures of the present invention. In the specification and drawings, the same reference numerals always refer to the same elements. Relevant terms and their derivatives should be interpreted as referring to orientations as described subsequently or as shown in the drawings discussed. Unless otherwise stated, these relative terms are for ease of description and do not require the system to be constructed or operated in a specific orientation.

[0048] Aspects of the invention relate to methods of making an electrode portion comprising a current collector element and a coating of a solid or semisolid electrolyte. Figure 2A , Figure 2B and Figure 3A As shown, the method includes at least the step of electroplating 300 a certain amount of anode metal composition 30 as a layer between the current collector element 10 and the electrolyte 20 covering the current collector element 10. The anode metal composition is deposited between the electrolyte 20 layer and the current collector element 10 by an electroplating process involving the directional transfer of corresponding ions, anode metal ions, from the electroplating electrolyte 302 to the current collector element 10 through the electrolyte layer. Figure 2B The most relevant aspects regarding the anodic metal plating process are described in more detail.

[0049] The anode metal composition typically includes or consists essentially of one or more alkali metals selected from lithium (Li), sodium (Na) and potassium (K). Lithium is preferred for its relatively favorable redox potential and achievable power density. It should be noted that the electroplating process differs from the in-situ anode metal electroplating process within the anode metal battery (e.g., during the initial charging cycle) in that, in contrast to extracting the electroplated lithium metal from the total lithium inventory within the battery within the closed environment of the battery, the present treatment results in the formation of an electrode portion (isolated) with a preloaded amount of lithium metal, thereby obtaining lithium from an external source. Importantly, the formed electrode portion obtained by the present electroplating method is different from the portion manufactured in a process involving an anode deposition method (e.g., lithium metal evaporation) prior to depositing a solid or semi-solid electrolyte 20. As will be described in more detail below, the electrode portion 1n formed according to the present disclosure differs most significantly in that the deposited layer of the anode metal is essentially covered by a layer of the previously deposited electrolyte 20. This layer advantageously covers the underlying anode metal already present from its deposition and during subsequent processing or storage stages, thereby mitigating the degradation of the deposited anode metal (e.g., lithium) due to reaction with active species from the environment (e.g., O2, N2, and CO2) that are known to react with the original alkali metal (e.g., lithium metal, Li 0 ), these reactive species are usually present in manufacturing dry chambers and even as unavoidable trace amounts when the processing is carried out under an inert atmosphere (e.g., argon), which would disadvantageously make the production highly complicated and expensive, especially for industrial-scale production.

[0050] The composite electrolyte is configured to allow the transport of anode metal ions while being sufficiently rigid and strong to separate the negative electrode portion from the corresponding positive electrode (cathode). In some embodiments, the electrode portion 1n can be incorporated into a battery structure, whereby the electrolyte 20 acts as a separator that electrically separates the anode from the opposing electrode 1p while allowing ions to be transported therebetween. The opposing electrode 1p includes an electronically conductive current collector 80 for providing / collecting electrons. The cathode current collector 80 can be, for example, as shown, provided as an electronically conductive film 81 on a carrier 82, preferably a flexible carrier.

[0051] In some embodiments, for example, Figure 1A As shown, the negative electrode portion can be incorporated into a battery structure 1000 including one or more separator structures 50 between the electrode portion 1n and the counter electrode portion 1p. Alternatively or additionally, the battery can include one or more electrolyte compositions such as a cathode electrolyte 60 to improve ion transport between the cathode and anode.

[0052] In any case, the electrolyte 20 includes one or more functional additives at least before electroplating, which react with the electroplated anode metal to form a layer known in the art as a solid electrolyte interface (SEI). During electroplating, the additive participates in the reaction with the anode metal to form the SEI. After electroplating, the amount of the additive is significantly reduced and can even be substantially zero.

[0053] The electrolyte 20 layer is also typically resistant to inward penetration of solvents included in the electroplating electrolyte 302 in order to avoid reaction of the originally plated anode metal with the solvents included in the electroplating electrolyte 302. The solid or semi-solid electrolyte 20 is typically a hybrid or composite electrolyte that includes a polymer matrix, a metal salt dispersed in the hybrid solid electrolyte (typically throughout the polymer matrix), and preferably one or more additives to improve anode metal ion conduction.

[0054] The polymer matrix may be formed of any suitable composition. Typically, the matrix includes one or more polymers known in the art, including but not limited to polyacrylates, polyethers, polyesters, polycarbonates, polyolefins, or copolymers thereof.

[0055] Thus, in some embodiments, the method includes the step of coating 200 the current collector 10 with a layer of the composite solid electrolyte 20 prior to electroplating.

[0056] In a strongly preferred embodiment, for example Figure 1BAs shown, the electrolyte 20 is formed as a stack including at least two different layers, the stack including i) a first layer 21 covering the current collector element 10, the first layer 21 at least initially comprising one or more functional additives that form a solid electrolyte interface (SEI) 40 layer by reacting with the electroplated anode metal composition 30, and ii) a second layer 22, the second layer 22 covering the first layer 30 and resistant to the inward penetration of the solvent included in the electroplating electrolyte toward the first layer and / or the electroplated anode metal composition 30. Providing a separate layer advantageously separates SEI formation from resisting inward penetration of the solvent included in the electroplating electrolyte. That is, the composition of the first layer including the SEI forming additive can be adjusted independently of the composition of the second layer that is resistant to or at least less permeable to the inward penetration of the solvent included in the electroplating electrolyte 302. Therefore, the multilayer composite solid electrolyte will include a first layer, i.e., an SEI forming layer 21, and a second layer 22, the second layer 22 being resistant to (e.g., substantially impermeable or at least more resistant than the first layer) the liquid electrolyte used for electroplating. Solvent resistivity or at least poor permeability can be conveniently obtained by selecting the matrix polymer and the solvent included in the plating electrolyte 302. For example, the matrix polymers can be selected to be incompatible with each other depending on the solvent used in the plating electrolyte 302. For example, the matrix polymer included in the electrolyte 20, especially in the second layer 22, can be selected to be poorly soluble or even substantially insoluble in the solvent, or at least more poorly soluble, preferably at least 50%, than the polymer included in the first layer 21 (including the SEI forming additive). Preferably, the matrix polymer included in the second layer has a solubility of ≤5 wt %, more preferably ≤5 g / kg, and even more preferably ≤1 g / kg in the solvent included in the plating electrolyte 302 under plating conditions.

[0057] To maintain ionic conduction throughout the electrolyte, both layers will typically contain salts of the corresponding anode metal. For lithium metal electrodes, these additives include Li salts such as LiTFSI (lithium bis(trifluoromethanesulfonyl)imide), LiClO4 (lithium perchlorate), LiFSI (lithium bis(fluorosulfonyl)imide), LiBF4 (lithium tetrafluoroborate), LiBOB (lithium bis(oxalate)borate), LiDFOB (lithium difluoro(oxalate)borate), LiTf (lithium trifluoromethanesulfonate) and / or LiTDI (lithium 2-trifluoromethyl-4,5-dicyanoimidazole).

[0058] In some embodiments, for example, Figure 1BAs shown, the electrode portion includes an additional ion diffusion layer 23. The ion diffusion layer 23 is provided on the electrolyte 20 coating along the outer face opposite to the current collector element 10. Before electroplating, the ion diffusion layer 23 is provided to the electrolyte 20. The additional ion conductive layer 23 includes such a composition and thickness: it enables metal ion transport, while at least helping to mitigate the entry of solvents included in the electroplating electrolyte 302 toward the electrolyte 20 and thus toward the anode metal composition 30 during electroplating. This layer generally includes an inorganic or ceramic composition, or is substantially formed by an inorganic or ceramic composition. Suitable compositions include aluminum oxide, titanium oxide, zinc oxide and LiPON. In addition (in the battery context), the ion diffusion layer 23 can protect the anode metal layer from the influence of solvents included in the liquid battery electrolyte composition (e.g., the anode electrolyte, if provided). The thickness of the ion diffusion layer 23 is generally thin enough to allow metal ions to pass through. The thickness is in the range of about 1nm to 10nm, preferably between 1nm and 5nm, for example about 1nm to 2nm. It was found that progressively thicker layers increasingly hindered ion conduction while providing little additional benefit in terms of mitigating solvent ingress. The ion diffusion layer 23 can be conveniently provided at a suitable thickness using known methods, including but not limited to dry vapor deposition methods such as PVD, CVD, and ALD. Each of the methods can be advantageously combined with the roll-to-roll processing disclosed herein.

[0059] SEI-forming additives known to form a stable SEI layer are well known in the art. Additives include, but are not limited to, succinonitrile; ionic liquids, such as N-propyl-N-methylpyrrolidinium; lithium salts, such as lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium bisoxalate borate, lithium fluoride, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium nitrate; or combinations thereof. Advantageously, the matrix polymer may be a polymer that is found to be advantageously conducive to SEI formation, including, but not limited to, polyethers, such as PEO or copolymers; and polycarbonates, such as polypropylene carbonate (PPC) or copolymers. J.Mol.Model.article:6, (2017), incorporated herein by reference, describes a variety of SEI-forming electrolyte additives for lithium-ion batteries. Typically, the SEI composition formed for Li batteries includes one or more of the following: LiF, Li alkyl carbonate, Li2CO3, Li2O, Li alkoxides, and the like. These compositions can be formed by reducing electrolytes, solvents and / or salts at the anode during battery formation. H. Wu et al. (Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes, published in Advanced Energy Materials Vol. 11, No. 5, 2021, 2003092), which is incorporated herein by reference, provides an overview of materials, additives and SEI formation on lithium metal anodes. The inventors found that for anode metals other than Li (e.g., K and / or Na), similar principles hold true in terms of additives, SEI formation and its protective properties.

[0060] The second layer may, but typically, contain similar or even identical metal salts in a different polymer matrix. The matrix may advantageously be specifically adjusted to resist penetration of solvents included in the plating electrolyte 302. In a preferred embodiment, the matrix polymer of the second layer comprises one or more polyfluorinated polymers, such as polyvinylidene fluoride (PVDF), PVDF-HFP, and polyacrylonitrile (PAN) or copolymers thereof. Alternatively or additionally, the matrix polymer of the second layer may comprise one or more of polyamide, polypropylene, and polyethylene.

[0061] To further improve metal ion conductivity, the solid or semi-solid electrolyte 20, preferably at least the second layer, may contain one or more inorganic filler particles, wherein the one or more inorganic filler particles include: one or more first type of filler particles, which include or are essentially composed of an inorganic dielectric composition; and / or one or more second type of filler particles, which include or are essentially composed of solid electrolyte particles such as LLZO, Li metal halide, LATP.

[0062] The dielectric may be based on a metal oxide or a metalloid oxide, for example, SiO2, TiO2, or a combination thereof. Preferably, the particles include or consist essentially of a high-k dielectric, i.e., a material having a dielectric constant exceeding about 4 at least in the temperature range of about 20°C to about 100°C. Preferably, the dielectric constant is ≥20, more preferably ≥40. Most preferably, the dielectric constant exceeds 100. Suitable materials include, but are not limited to, metal titanates (MTiOx), including but not limited to titanates based on barium, strontium, calcium, copper, and yttrium, and combinations and / or derivatives thereof, such as doped metal titanates. Preferred examples include barium titanate, strontium titanate, and combinations thereof. In addition to improving ionic conductivity, it has been found that the introduction of dielectric particles advantageously improves the homogenization of the electric field across the mixed solid electrolyte layer. The inventors believe that the introduction of dielectric fillers can homogenize the metal ion transport across the layer and / or mitigate the formation of dendrites at the interface with the anode material due to repeated charge and discharge cycles. The inventors have found that the higher the dielectric constant, the better the homogenization. Preferably, the particles are predominantly discrete particles having a uniform distribution within the hybrid solid electrolyte layer and / or its sublayers. In addition to aligning the field, it has been found that the dielectric particles advantageously reduce the softening and / or glass transition temperature of the polymer matrix, thereby contributing to the ionic conductivity of the hybrid solid electrolyte.

[0063] The electrolyte 20 will typically have a thickness in the range of about 10 microns to 50 microns. The thicker layer improves the protection of the bottom-plated anode metal from environmental influences and contact with the plating solution. The electrolyte 20 can be thicker, for example up to 100μm or more, but the inventors have found that the benefits of the anode metal layer may no longer increase proportionally. The first layer (SEI formation layer 21) typically has a thickness of more than 500nm, preferably ≥1μm or ≥2μm, for example in the range of about 1μm to 10μm. Thinner layers may reduce the effectiveness of the formed SEI layer in protecting the anode metal from degradation due to reaction with the environment. The second layer (solvent resistant layer 22) typically has a thickness t22 of ≥5μm, preferably ≥10μm, for example in the range of about 10μm to 40μm.

[0064] The thickness of the formed anode metal layer can be advantageously adjusted to a desired specification, for example by controlling one or more electroplating conditions, such as by referring to Figure 2B and Figure 4A In more detail, the thickness t30 of the deposited anode metal layer 30 generally depends on the intended application of the electrode portion 1n. For some battery applications, the thickness of the anode metal layer, such as a lithium metal layer, may be adjusted within a range of 1 μm to 5 μm.

[0065] In some embodiments, for example, Figure 1AThe current collector element 10 shown may be a metal element, for example a planar element such as a foil, formed of any metal composition that is stable (does not participate in redox reactions) during battery operation. Typically, the metal may include copper or nickel, or even consist essentially of copper or nickel. In other or additional embodiments, for example Figure 1B As shown, the current collector element 10 may be provided as an electron conducting film 11 , such as a copper film, provided along a face of a carrier 12 , such as a polymer or metal foil.

[0066] In a preferred embodiment, for example Figure 2A , Figure 2B and Figure 3A As shown, the current collector element 10 is formed as a flexible foil, for example as a metal film or as a conductive film 11 on a flexible carrier 12. Typically, the foil has a thickness in the range of 1 μm to 50 μm. Preferably, the foil has a thickness in the range of 5 μm to 15 μm, which provides a good balance of flexibility and handling characteristics.

[0067] Hence, the method 100 may advantageously be configured for roll-to-roll processing.Advantageously, the current collector element may have an industrially relevant width, such as up to 3 m, such as in the range of 0.3 m to 2.5 m, thereby enabling large-scale production of preloaded electrode parts.

[0068] Figure 2A A method 100 configured for continuous roll-to-roll processing of manufacturing an electrode portion as disclosed herein is schematically shown. In the method, a current collector element 10 supplied from a roll (left) is delivered to a station for electroplating 300 a certain amount of an anode metal composition 30 as a layer between the current collector element 10 and an electrolyte 20 covering the current collector element 10 by electroplating.

[0069] Prior to electroplating, the method includes the step of coating 200 the current collector 10 with a layer of a composite solid or semi-solid electrolyte 20. Although not shown in full detail, the solid electrolyte 20 is formed as a stack of two different layers, the stack of two different layers including: i) a first layer 21 covering the current collector element 10, the first layer 21 at least initially comprising one or more functional additives forming a solid electrolyte interface (SEI), and ii) a second layer 22 covering the first layer 30 and being resistant to inward penetration of solvents included in the electroplating electrolyte. Each of the layers included in the electrolyte 20 can be provided using methods known in the art, including slot die coating, extrusion, spin coating, dip coating, etc.

[0070] After electroplating 300 a certain amount of anode metal composition 30, the formed preloaded electrode portion 1n is collected on a roll ( Figure 2AThe electrode portions formed can optionally be cut into blocks for storage and / or direct processing, for example to manufacture batteries.

[0071] It will be appreciated that, as an alternative, the method may be configured to process on a slice-by-slice basis.

[0072] Figure 2B , Figure 3A and Figure 4A shows electroplating 300, wherein Figure 4A Provided Figure 2B A more detailed view of the area marked in .

[0073] In general, the electroplating process produces a metal coating, i.e., an anode metal coating 30, on the current collector element 10 by reducing the cations of the metal by means of direct current. The current collector element 10 acts as the cathode (negative electrode) of the electrolytic cell; the electroplating electrolyte is a solution comprising a salt of the metal to be coated (e.g., a Li salt). The anode (positive electrode) is generally formed by an electrode comprising the corresponding metal, which is generally a bulk of the metal or a bulk of some inert conductive material. The current is provided by an external power supply.

[0074] In an embodiment, if Figure 2B and Figure 3A As shown, a coating having an electrolyte 20 (for clarity, in Figure 2B The current collector element 10 (shown as a single layer in FIG) is conveyed through an electrochemical plating bath 301. Since electroplating results in the formation of a protective SEI layer, the electroplating in particular and the entire production process can be conveniently performed in a dry room environment without the need to reduce or eliminate the O2, N2 and / or CO2 levels in the ambient atmosphere.

[0075] Bath 301 contains a liquid plating electrolyte 302 in which the membrane is immersed. For Li metal plating, the electrolyte will include a lithium salt, such as one or more of LiTSI, LIFSI, LiNO3, LiF, LiClO4, LIF, LIBF4, LiBOB, LiDFOB and LiPF6; and a solvent. The solvent is typically selected from one or more of the following: ionic liquids, carbonates, ethers, fluorinated ethers, fluorinated carbonates, organic phosphates, solvents with sulfonyl groups, ester solvents. For example, one or more of the following: DOL (dioxolane), DME (dimethoxyethane), EC (ethylene carbonate) and DEC (diethyl carbonate), DMC (dimethyl carbonate), FEC (fluoroethylene carbonate), VC (ethylene carbonate), PC (propylene carbonate), HFE (hydrofluoroether), FEMC (trifluoroethyl methyl carbonate). It will be appreciated that the choice of solvent and composition of the electrolyte 20, especially the second layer 22, will be mutually selected to avoid solvent penetration through the solid or semi-solid electrolyte 20. The temperature of the bath during electroplating depends on the type of metal to be plated. For lithium plating, the temperature is typically controlled to a temperature in the range of 20°C to 80°C.

[0076] The electroplating electrolyte 302 is in contact with a source 310 of anode metal ions (e.g., Li ions). Alternatively, the source can be anode metal ions provided by a certain amount of anode metal salt in the electrolyte itself. In this case, the anode metal salt will need to be replenished periodically or continuously during electroplating to prevent the anode metal ions from being depleted. Preferably, the source is provided by a solid source such as a metal or metal oxide. The source can be connected as the cathode (negative pole) of the electrolytic cell, thereby continuously replenishing the anode metal ions lost by electroplating to the current collector element 10 (connected as the anode of the tank).

[0077] For lithium plating, the source may be a Li metal source. Advantageously, the source may comprise an oxide, hydroxide or carbonate that is typically present on the surface of commercially available lithium metal (eg, foil).

[0078] like Figure 4A As described in detail in the above, the anode metal ions 31 are transferred through the solid electrolyte 20 layer for electroplating as the anode metal 40 layer onto the anode metal composition 30 between them. 0 ) reacts with the SEI additive included in the first layer 21 to form the SEI layer 40. This is because the SEI layer enables further transport of anode metal ions, and the anode metal can be electroplated through the SEI layer. Note that the foil is transported (at Figure 4A In the direction marked as D), the area A1 initially without the anode metal layer becomes an area A2 comprising a preloaded amount of anode metal.

[0079] The SEI layer forms at the interface between the electroplated anode metal and the electrolyte 20. The formation of the SEI layer is terminated by the self-limiting nature of the SEI formation process or by consumption of the SEI formation additive.

[0080] The SEI layer forms an inherent protection for the underlying anode metal, mitigating its degradation due to loss of Li metal caused by reaction with the environment. The electrolyte 20, and in particular the second layer, protects the formed anode metal from reacting with the solvent included in the electroplating electrolyte 302. Because both protective layers are present when the anode metal is electroplated, the formed anode metal layer can be exceptionally pure and free of degradation products compared to electrode portions manufactured by depositing or generating the electrolyte and / or SEI layer only after the deposition of the anode metal is completed.

[0081] The thickness of the electrolyte 20 is preferably in the range of 10 μm to 50 μm. The first layer 21 including the SEI forming additive preferably has a thickness t21 at least initially in the range of 1 μm to 10 μm. The second layer included in the electroplating electrolyte 302 that is resistant to the penetration of the solvent typically has a thickness in the range of 10 μm to 40 μm. The SEI layer formed can advantageously be a conformal covering layer having a thickness exceeding about 1 μm. More preferably thicker, for example ≥ 2 μm, such as in the range of 1 μm to 5 μm, in the range of 2 μm to 5 μm, in the range of 1 μm to 10 μm, or in the range of 2 μm to 10 μm.

[0082] Anode metal (e.g., Li) electroplating is based on known principles. Electroplating can be performed in a DC mode, a pulse mode, or a reverse pulse mode. By controlling one or more electroplating conditions, the amount of the electroplated anode metal layer can be conveniently controlled.

[0083] In a preferred embodiment, the method comprises controlling the amount, e.g. thickness (t30), of the electroplated anode metal layer 30, preferably by a controller C, by adjusting one or more of: adjusting the amplitude, duration and / or pulse shape of the electroplating current I during electroplating, and / or controlling the contact time of the substrate with the electroplating electrolyte. Thus, the electrode portion (1n) may be provided with a specific amount of anode metal, e.g. a predefined target.

[0084] For rechargeable anode metal ion batteries, e.g. Figure 1A As shown, the thickness of the anode metal layer is preferably ≥ 1 μm, more preferably ≥ 2 μm, for example 5 μm to 10 μm. Optionally, up to 50 μm or even 100 μm. The thicker the anode metal layer, the greater the buffer capacity of the battery and the longer the operating life may be. Thinner layers are possible, but provide less buffer capacity and / or may become discontinuous, thereby providing reduced performance with respect to homogenization of the plated anode metal during battery charging operation.

[0085] For secondary lithium sulfur (Li-S) or lithium air (Li-air) batteries, for example Figure 4B and Figure 4C As shown, the anode metal layer defines the lithium inventory of the battery. Therefore, the amount of pre-loaded anode metal per unit area is typically large, such as ≥50 μm, preferably ≥100 μm, such as between 1 μm and 200 μm, or more.

[0086] Preferably, the source is in the form of a volume, such as Figure 2B , Figure 3A and Figure 3B As shown. For example, a roll comprising a body 313 covered with a film or layer (e.g., foil) as an anode metal source 311. Preferably, the roll and / or delivery system is configured to adjust the position of the relative separation distance between the source and the current collector element 10. For example, by mounting the roll on an adjustable holder 314, as shown.

[0087] In a preferred embodiment, the coil and / or system, source and / or coil are adjustable so that during operation, the source can be in direct contact with the outer face 20f of the electrolyte 20. Adjusting the separation distance between the source and the electrolyte 20 until direct contact advantageously reduces the ion diffusion path length between the source and the current collector element 10. The adjustable coil can also advantageously maintain the separation distance, such as direct contact, between the coil and the electrolyte coating 20 even when the anode metal on the coil is consumed.

[0088] In some embodiments, for example, Figure 2B As shown, the roll is patterned to include portions without anode metal source. For example, patterning the source by including gaps 311g around the perimeter of the roll without anode metal source can advantageously produce electrode portions 1n where the electroplated anode process layer includes areas with reduced thickness or even gaps without electroplated anode metal.

[0089] In some embodiments, the substrate foil is guided between a pair of rolls 310, 320 configured to apply compressive pressure to the layer of anode metal composition 30 formed during electroplating, preferably between an anode metal roll and an oppositely positioned adjustable counter roller 320.

[0090] Applying contact pressure to the foil when depositing a layer on the anode metal can advantageously reduce the deposition of the anode metal, such as Li 0 In addition, such a configuration can be used to facilitate the application of an electric field (E-field) at the electroplating point. In addition, applying contact pressure to the foil when depositing a layer on the anode metal can advantageously reduce the total volume of the electroplating electrolyte 302.

[0091] In some embodiments, for example, Figure 2B As shown (depicting the rolls spaced a distance from the foil), an elastomeric layer 312 is disposed about a body 313 of at least one of the rolls 310. The elastomeric layer may advantageously even out applied contact forces by mitigating peak forces due to, for example, surface roughness.

[0092] In other or additional preferred embodiments, the foil is wrapped around a portion of the periphery of the electroplating coil, e.g. Figure 5A As shown. Figure 3A Wrapping the foil around a portion of the roll forms an overlap with the roll with an increased contact area compared to the relatively narrow or line contact shown. For a given conveying speed, wrapping the foil around a portion of the roll can advantageously increase the contact time (plating time) between the foil and the roll. Increasing the contact time can advantageously reduce the area plating rate. The length L of the overlap can be varied, for example, by positioning the displaceable roll. In some embodiments, by using one or more additional guide rolls, the overlap can be ≥ 10% or more of the outer surface area of ​​the roll, such as ≥ 20% or ≥ 30%, up to about 50% or even more, such as up to about 75%.

[0093] In a preferred embodiment, the plating rate is set to ≤ 5 μm / h. Lower plating rates have been found to provide more consistent, uniform plating. Lithium anode metal quality has been found to be best at plating rates ≤ 1 μm / h.

[0094] In yet another or additional preferred embodiment, a porous separator 315 is provided between the coil 310 and the substrate, such as a foil, during electroplating. The separator can advantageously reduce the total volume of the plating electrolyte 302 in the bath, or even substantially contain the total amount of the plating electrolyte 302. In some embodiments, the porous separator is provided as a temporary layer on the solid or semi-solid electrolyte 20. Alternatively or additionally, the separator can be supplied as a separate sheet between the foil and the coil, for example, to be transported together with the foil by the coil, preferably the anode metal coil. Figure 3A The electroplating process is shown, wherein the separator 315 is conveyed with the foils 10, 20 by the anode metal roll 310. In a preferred embodiment, for example as shown, the separator 315 is preferably conveyed as an invitation loop by means of one or more adjustable tension rolls 318. Note that in the embodiment as shown, the anode metal roll 310 and the counter roll 320 have been adjusted to contact the foils. The controller C is set to maintain the contact pressure. Note that as the anode metal 311 is consumed over time, the position of the rolls 310, 320 can be adjusted to maintain contact with the foils.

[0095] Yet further alternatively or additionally, for example Figure 3B As shown, the separator may be configured as a layer 315 along an exterior face of the roll 310 .

[0096] Providing a porous separator with a working electrolyte along the face of the roll or as a separately delivered sheet 315 alleviates the need to remove the separator from the product after processing. Preferably, the separator is a (elastic) compressible separator. Providing a compressible (elastic) separator advantageously improves contact with the electrolyte 20 and enables reduction / buffering of peak forces caused, for example, by undulations on the roll and / or product.

[0097] It will be appreciated that for the electroplating of one or more other or additional anode metals (eg, Na or K), the electroplating source, electroplating electrolyte, and conditions will be appropriately adjusted.

[0098] In some embodiments, the electroplating can be a substantially dry electroplating process. The dry electroplating process can be achieved by using a dry or semi-dry electroplating electrolyte layer or belt between the foil and the anode metal source. The dry or semi-dry electroplating process reduces or eliminates adverse reactions between the solvent and the electroplated anode metal. In some variations, the dry or semi-dry electrolyte can be a solid or semi-solid electrolyte layer 316 disposed around the electroplating coil, such as Figure 5A In other embodiments, the dry or semi-dry electrolyte may be provided as a sheet or strip between the roll and the foil. It will be appreciated that a small amount of liquid electrolyte may be provided as a wetting agent to improve contact with the foil. In the case of a dry or semi-dry electroplating process, the second electrolyte layer may be understood to provide structural integrity to the stack. In particular, the second layer 22 (compare Figure 4A ) can be understood to be formed of a relatively harder composition than the first layer (e.g., a relatively harder polymer or even a ceramic layer as disclosed herein). This allows the first layer to be relatively soft, or even a gel, which is beneficial in mitigating damage caused by contact forces during dry or semi-dry electroplating. Figure 2C to Figure 2D and Figure 5C In conjunction with the above), a gel-like first layer is particularly envisaged.

[0099] In addition to and as an alternative to electroplating from an external source, the electrode portions disclosed herein can also be advantageously used in battery products without providing a preloaded amount of anode metal (e.g., lithium) to the electrode. In such applications, the electroplating electrolyte and anode metal source can be provided in situ within the battery, such as a cathode composition and a solid electrolyte from which the anode metal is electroplated during an initial battery charging routine.

[0100] In some preferred embodiments, for example Figure 5BAs shown, one or more inorganic layers 25 are provided on top of the second layer 22 of the electrolyte coating 20. Alternatively or additionally, one or more additional inorganic layers may be provided between the first layer 21 and the second layer 22 of the electrolyte coating 20. One or more inorganic layers 24, 25 may further reduce the crosstalk between the first layer and the electroplating environment. The inorganic layers may, but not necessarily, have the same or similar compositions. In either case, the ceramic layer will be superphilic to the anode metal salt (alkali ions or alkaline earth ions, e.g., lithium ions). Anode metal ions, e.g., Li ions, conductivity may be achieved by a suitably thin (e.g., ≤5 nm) composition or a composition such as LiPON that is essentially anode-metal-ion conductive.

[0101] Figure 5B , Figure 5C and Figure 5D An exemplary electrode portion 1n' is shown before preloading the anode metal composition. Before preloading by electroplating means that the electrode portion can be understood to be substantially free of anode metal. Therefore, these parts can be understood as starting products for the electroplating process described herein. Generally consistent with the present disclosure, these parts include at least a current collector element 10 and an electrolyte coating 20. The electrode portion does not include a pre-deposited amount of anode metal. The electrolyte coating comprises: i) a first layer 21 covering the current collector element 10, the first layer comprising one or more functional additives, the one or more functional additives forming a solid electrolyte interface 40 layer when reacting with the electroplated anode metal composition 30 provided by electroplating; and ii) a second layer 22 covering the first layer as disclosed herein. The second layer can be understood to be more resistant to electroplating solvents than the first layer, and in particular more resistant to the ingress of solvents used in subsequent electroplating.

[0102] In some embodiments, a thin ceramic layer 24 is disposed between the first layer 21 and the second layer 22 of the electrolyte coating to further mitigate the entry of solvent into the second layer and / or exchange of solvent from the second layer while enabling Li ion conduction. In other or additional embodiments, the thin layer of ceramic 24 mitigates solvent entry and / or exchange while enabling Li ion conduction. In yet another embodiment, for example, as shown in the figure, the second layer 22 is sandwiched between the first ceramic layer and the second ceramic layer. In addition to mitigating solvent entry / exchange, the ceramic layer can increase the rigidity of the electrolyte coating 20. This may be particularly beneficial in the case where the current collector element 10 is a 3D structured current collector comprising a plurality of outwardly extending elongated protrusions 10p combined with a gel-like or semi-solid first layer.

[0103] In other or additional variations, a double-sided coated anode is provided. Figure 5DAn anode portion 1n' is shown having a double-coated current collector element (before electroplating), the double-coated current collector element comprising a carrier foil 1211 coated on opposite sides with a respective one of the electronically conductive metal films 11-1, 11-2, each of which is provided with a respective one of the electrolyte coatings 20-1, 20-2 as disclosed herein.

[0104] These double-sided electrodes can be advantageously used for the assembly of battery cell stacks.Depending on the nature of the subsequent covering layers provided on either side, for example cathodic or anodic, these double electrodes can be used for the assembly of tandem or bipolar cell stacks.

[0105] In some preferred embodiments, for example Figure 1B As shown, the electrode portion 1n includes a nucleation layer 15. Applying a nucleation layer or alloying layer to the current collector element 10 (e.g., directly to the metal coating 11 as shown) can advantageously improve the uniformity of the anode metal covering layer formed thereon during subsequent electroplating. The nucleation layer is considered to act as a wetting layer between the current collector element 10 and the anode metal composition 30. For lithium-based batteries, the seed layer can be referred to as lithium-philic. For other metals, the layer can be referred to as sodium-philic or potassium-philic, for example. The seed layer generally includes or is substantially composed of an electronic conductive composition, including but not limited to one or more of Zn, Sn, In, Mg, Al, Ti, Mo, Cr, carbon graphite, graphene-like, etc. The wetting effect is considered to be based at least in part on the alloying of the seed layer composition with the anode metal composition. When such an alloying layer is relatively thin (e.g., 10nm to 500nm), it can be regarded as a seed layer. When the layer is thicker (up to, for example, 20μm), it can be regarded as the main material of the anode metal. Thus, the subsequently provided anode metal layer may be considered to be an alloy of one or more anode metals and a seed composition (e.g., Sn-Li, In-Li, Zn-Li, etc., in the case where lithium is used as the anode metal). In either case, the seed / alloying layer enables uniform anode metal deposition on the current collector element, thereby improving battery performance and reliability.

[0106] Alternatively, the seed composition may include an oxide, such as a hydroxide, such as ZnO x These oxides will be reduced by contact with the relatively more electropositive anode metal composition.

[0107] The seed layer 15 is typically provided directly prior to depositing the electrolyte 20. Suitable methods include ALD, PVD, CVD and electroplating. For the structured current collector element 10, for example, as described with respect to Figure 2C and Figure 2DAs discussed, conformal layer deposition methods such as ALD and / or electroplating may be preferred.Alternatively, the nucleation layer may be electroplated through the electrolyte layer 20 or another solid electrolyte layer.

[0108] It will be appreciated that the present disclosure also relates to an electrode portion, which can preferably be obtained by the method disclosed herein, and in particular to an electrode portion comprising a current collector element having a solid or semi-solid electrolyte layer disposed thereon, and a preloaded amount of an anode metal composition disposed as a layer between the current collector element and the electrolyte.

[0109] Additionally, the present disclosure relates to energy storage devices, such as batteries, comprising the electrode portions (1n), and methods of making such devices.

[0110] Go to Figure 1A , depicts a preloaded electrode portion 1n comprising an anode metal composition 30 disposed as a layer between a current collector element 10 and a solid electrolyte layer 20. Figure 1B As shown in more detail in , a solid electrolyte interface (SEI) layer 40 is formed along the interface between the layers of electrolyte and anode metal composition 30 .

[0111] In a preferred embodiment, for example as shown, the electrolyte 20 comprises i) a first layer 21 covering the current collector element 10, and ii) a second layer 22 covering the first layer. The SEI layer obtained by the disclosed method can advantageously have a thickness (t30, see Figure 4A ). As described in detail with reference to the method, the first layer comprises one or more functional additives at least before electroplating for forming a solid electrolyte interface 40 layer by reaction with the electroplated anode metal composition 30. The second layer is resistant to inward penetration of a solvent included in the electroplating electrolyte 302 toward the electroplated anode metal composition 30.

[0112] Due to the protective SEI layer formed directly with the deposition of the anode metal, the electrode is characterized by reduced degradation and / or uniformity of the pre-loaded amount of anode metal. In contrast, an electrode including a pre-loaded anode metal layer deposited before forming the SEI layer will have a relatively large Li loss and / or corresponding non-uniformity due to products of reaction with the environment, such as air.

[0113] In some embodiments, for example, Figure 1B As shown, the electrode portion 1 n includes a seed layer 15 .

[0114] Advantageously, the preloaded electrode portion 1n may be flexible, such as a foil, as described with respect to Figure 2A and Figure 2B As described.

[0115] In some embodiments, the current collector element is a 3D structured element comprising a plurality of outwardly extending elongated protrusions. Figure 2C An exemplary current collector element 10 is shown, which includes protrusions 11p extending outwardly from a conductive base 11b. The base may be a metal foil or film. Alternatively or additionally, the base may be provided on a carrier, such as a flexible carrier 12. The base with protrusions, such as in the form of pillars or columns, forms a support structure on which a solid or semi-solid electrolyte 20 covering is deposited. Thus, the structure is used to carry a certain amount of anode metal composition deposited by electroplating.

[0116] Preferably, the protrusions are electrically conductive at least along the outer faces (eg, sidewalls) to improve current transfer to / from the base.The formed preloaded 3D electrodes advantageously provide improved performance in terms of capacity and rate.

[0117] It will be appreciated that when the electrolyte 20 is provided as a multilayer stack, the first layer 21 comprising the SEI additive will preferably extend into the 3D current collector, while the second layer 22 - the solvent resistance layer - will preferably be provided as a planar overlying layer (not extending between the pillars), e.g. Figure 2D shown.

[0118] Alternatively, the electrolyte may be formed as a monolayer that is resistant to inward penetration of a solvent included in the plating electrolyte and includes a SEI-forming additive.

[0119] Now refer to Figure 1A , Figure 3B and Figure 3C Exemplary embodiments related to energy storage devices including the electrode portions 1n disclosed herein and methods of making such devices are described.

[0120] Figure 3C A method 500 of manufacturing a battery 1000 is schematically shown. The method comprises: providing 501 an electrode portion 1n having a preloaded amount of anode metal as disclosed herein; and assembling 510 the portion opposite to a counter electrode portion 1p in a battery structure. Figure 1A Said, the method may further comprise one or more of the following operations: providing one or more additional separator 50 structures between the electrode portion 1n and the counter electrode portion 1p. Alternatively or additionally, the method may comprise providing one or more electrolyte compositions such as cathode electrolyte 60 to improve ion transport between the cathode and the anode.

[0121] Figure 1A , Figure 4B and Figure 4CAn exemplary embodiment of a battery 1000 including an electrode portion 1 n and a counter electrode portion 1 p as disclosed herein is shown.

[0122] In some preferred embodiments, for example Figure 1A and Figure 2B As shown, the cell includes a cathode composition 70 disposed along a face of a counter electrode portion 1p.

[0123] In a particularly preferred embodiment, the battery is formed as a secondary lithium metal ion battery in which the cathode composition 70 and the layer of the preloaded anode metal composition 30 both include lithium. Note that the preloaded lithium metal layer can advantageously provide a buffer amount of lithium in addition to the lithium inventory provided by the cathode composition. The preloaded lithium metal layer acts as a nucleation layer or plating layer for subsequent in-situ electroplating of lithium metal (e.g., during initial or subsequent charging operations), and acts as a buffer to replace the loss of the lithium inventory composition during battery operation, at least during initial processing in lithium metal plating and deplating processes. The composition of the cathode composition and methods of providing the cathode composition 70 are well known in the art. Suitable compositions include lithium metal salts, for example, LiM oxide compositions or lithium metal sulfide (LiM-S) compositions. For example, a Li-loaded ceramic, such as Li x M y O z or Li a M b PO4 (wherein M is typically one or more of Co, Ni, Al, Mn, Fe and Sn).

[0124] In other embodiments, the available anode metal inventory is determined primarily or even solely by the amount of preloaded anode metal of the preloaded lithium metal layer 30 .

[0125] Figure 4B A secondary lithium battery formed as a secondary lithium-sulfur (Li-S) battery is shown. The electrode portion 1n is separated from the counter electrode by an additional separator 50, which includes a positive current collector structure 80 having a sulfur cathode (S8) cathode composition. In view of the electrolyte coating 20 provided on the current collector element 10, the additional separator 50 is optional. However, the additional separator 50 can be applied to improve ion transport between the anode and the cathode. The battery during the discharge cycle is depicted, wherein electrons from the lithium oxidation reaction at the anode travel to the cathode via an external load. The lithium ions in the electrolyte migrate to the cathode, where the sulfur is reduced to lithium sulfide (Li2S). During the recharge cycle, the sulfur is reoxidized and the lithium ions return to be reduced at the anode.

[0126] Figure 4CA secondary lithium battery formed as a secondary lithium air (Li-S) battery is shown, which uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce the flow of electrons e-, labeled as current "I". Similar to the Li-S battery, the anode metal (lithium) inventory within the battery is primarily or even solely determined by the amount of pre-loaded anode metal (lithium) that circulates between the anode and cathode during the respective charge and discharge operations.

[0127] The cell is depicted in a partially charged state during a charge cycle (with an optional additional separator 50), whereby a portion of the lithium inventory is reduced (metallic state) at the anode 30' and the remainder is contained in an oxidized form 70' at the cathode.

[0128] For the purpose of clarity and concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having a combination of all or some of the features described. Of course, it should be appreciated that any of the above embodiments or processes may be combined with one or more other embodiments or processes to provide even further improvements in finding and matching designs and advantages.

[0129] In interpreting the appended claims, it should be understood that the word "comprising" does not exclude the presence of other elements or actions than those listed in a given claim; the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; any reference numerals in a claim do not limit its scope; several "devices" may be represented by identical or different items or implemented structures or functions; unless otherwise specifically stated, any disclosed device or part thereof may be combined together or separated into further parts. Where one claim refers to another claim, this may indicate synergistic advantages achieved by combining their respective features. However, the fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot also be used to advantage. Therefore, the present embodiment may include all working combinations of the claims, each of which may in principle refer to any preceding claim unless the context clearly excludes it.

Claims

1. A method (100) of manufacturing an electrode portion (1n) comprising a current collector element (10) and an electrolyte coating (20), the method comprising: A quantity of an anode metal composition (30) is deposited (300) as a layer between the current collector element (10) and the electrolyte (20) covering the current collector element (10) by an electroplating process involving the directed transfer of anode metal ions (31) from a plating electrolyte (302) to the current collector element (10) through the electrolyte coating, wherein: The electrolyte coating (20) comprises: i) a first layer (21) covering the current collector element (10), the first layer at least initially comprising one or more functional additives that form a solid electrolyte interface (40) layer by reaction with the electroplated anode metal composition (30); and ii) a second layer (22) covering the first layer, the second layer being more resistant than the first layer to inward penetration of a solvent included in the electroplating electrolyte (302) toward the electroplated anode metal composition (30).

2. The method according to claim 1, comprising the steps of: depositing a first electrolyte composition or a precursor thereof onto the current collector element (10) to form the first layer (21), and A second electrolyte composition or a precursor thereof is deposited onto the deposited first layer to form the second layer (22).

3. The method according to claim 1 or 2, wherein: The current collector element (10) is formed as a flexible foil and wherein the method is configured as a roll-to-roll process comprising conveying the foil through a station (301) configured for loading a segment of the conveyed foil by the electroplating process.

4. A method according to any one of the preceding claims, wherein: The anode metal source (311) is an anode metal coil, preferably a lithium metal coil (310).

5. A method according to any of the preceding claims, comprising controlling the amount of the plated anode metal layer (30), such as the thickness (t30), preferably by a controller (C) according to a predefined target by one or more of the following operations: adjusting the amplitude, duration and / or pulse shape of the plating current (I) during the plating, and / or controlling the contact time of the substrate with the plating electrolyte.

6. A method according to any one of the preceding claims, comprising the step of coating (200) the current collector element (10) with one or more layers (15) of a composition alloyed with the anode metal composition (30) before depositing (300) the anode metal composition and before providing the electrolyte coating.

7. A method according to any one of the preceding claims, wherein: During electroplating, the substrate (10) is guided between a pair of rolls (310, 320), preferably the anode metal roll and an oppositely positioned counter-roll, configured to apply compressive pressure to the layer of anode metal composition (30) being formed.

8. The method according to any one of claims 4 to 7, wherein: During electroplating, a porous separator (315) is disposed between the anode metal coil (310) and the electrolyte (20).

9. The method according to any of the preceding claims, comprising providing an ion diffusion layer (23) on the electrolyte (20) along an outer face opposite to the current collector element (10), the ion diffusion layer (23) comprising a composition configured to further resist entry of a solvent included in the plating electrolyte (302) toward the electrolyte (20).

10. An electrode part (1n), preferably obtainable by a method according to any one of claims 1 to 9, comprising: A current collector element (10) having an electrolyte coating (20) disposed thereon, the electrolyte coating comprising: i) a first layer (21) covering the current collector element (10), the first layer optionally comprising one or more functional additives, the one or more functional additives forming a solid electrolyte interface (40) layer when reacting with an electroplated anode metal composition (30) provided by electroplating; and ii) a second layer (22) covering the first layer, the second layer being more resistant to electroplating solvents than the first layer, a preloaded amount of an anode metal composition (30) disposed as a layer between the current collector element (10) and the electrolyte coating (20), and A solid electrolyte interface (40) is formed as a layer along the interface between the coating layer of the electrolyte and the layer of the anode metal composition (30).

11. The electrode portion (1n) according to claim 10, wherein The current collector element (10) is a flexible foil.

12. The electrode part (1n) according to any one of claims 10 to 11, wherein The current collector element (10) comprises a plurality of elongated protrusions (11p) extending outwardly from a conductive base (11b).

13. An electrode portion (1n') for use in an electroplating process according to any one of claims 1 to 9, said portion comprising: a current collector element (10), and an electrolyte coating (20) disposed thereon, wherein the electrode portion does not include a pre-deposited amount of anode metal, and wherein the electrolyte coating comprises: i) a first layer (21) covering the current collector element (10), the first layer comprising one or more functional additives, the one or more functional additives forming a solid electrolyte interface (40) layer when reacting with a plated anode metal composition (30) provided by electroplating; and ii) a second layer (22) covering the first layer, the second layer being more resistant to electroplating solvents than the first layer.

14. The electrode portion according to any one of claims 10 to 13, wherein The electrode portion is a double-sided electrode portion having respective ones of the electrolyte coatings disposed on opposite sides of the current collector element.

15. A method (500) of manufacturing a battery (1000), comprising: manufacturing an electrode part (1n) according to any one of claims 1 to 9, and The obtained portion is assembled to face the counter electrode portion (1p).

16. A battery (1000) comprising an electrode portion (1n) according to any one of claims 10 to 14 and a counter electrode portion (1p) positioned across the electrode portion (1n).

17. The battery (1000) according to claim 16, formed as a secondary lithium metal ion battery, wherein: The preloaded layer of anode metal composition (30) includes lithium, and the battery further includes a cathode composition (70) including lithium ions, whereby the preloaded lithium metal layer provides a buffer amount of lithium in addition to the lithium inventory provided by the cathode composition.

18. The battery (1000) according to claim 16, formed as a secondary lithium sulfur battery or a secondary lithium air battery, wherein: The layer of anode metal composition (30) includes lithium which provides the total lithium inventory of the battery.

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