Process for Producing Anodes for Lithium Batteries

Abstract

The present invention provides a method for producing a negative electrode for a lithium battery. The method includes providing a current collector, forming a layer of protective material on the current collector, depositing a lithophilic material on the layer of protective material, and depositing a molten lithium material on the layer of lithophilic material. The lithophilic material and the molten lithium material then react to form the negative electrode active material. The current collector and / or at least one other layer of the negative electrode may include a continuous 3D structure on its surface. The protective material deposited on the current collector forms a barrier between the current collector and the lithium in the negative electrode active material, and thus the formation of cracks in the current collector is avoided.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 299,247, filed January 13, 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] The present invention relates generally to a method for producing an anode for a lithium battery. More specifically, the present invention relates to a method for producing an anode in which an active anode material is formed after reaction between a lithophilic material and a lithium material in molten form or after depositing a lithium material on a lithophilic surface. The current collector and / or at least one other layer of the anode may include a continuous 3D structure. [Background technology]

[0003] Lithium metal, with a theoretical specific energy of 3860 mAh / g, constitutes a good anode material for energy storage systems (ESS) or batteries, compared to materials such as graphite, which has a theoretical specific energy of 372 mAh / g.

[0004] To increase the energy density of the battery and reduce the manufacturing costs of the negative electrode, a thin foil of Li metal is needed. However, Li has low mechanical strength and electronic conductivity (less than 5 and 3 times that of copper and aluminum, respectively). Thus, thin free-standing Li is difficult to manufacture and handle. It is known in the art to use a thin layer of Li deposited on a substrate made of a conductive material. Typically, a substrate, also called a current collector, is selected that has good mechanical properties and good electronic conductivity. A layer of Li with a thin thickness of 4 to 5 micrometers on a substrate also constitutes a better solution than using free-standing Li.

[0005] Methods for depositing thin layers of Li on metal substrates are known in the art. Such methods include, for example, physical vapor deposition (PVD) techniques. However, several drawbacks are associated with PVD, such as the fact that the deposition rate is rather low and the whole technique is very expensive.

[0006] It has also been observed that when a layer of Li is deposited on the current collector, interactions occur between the Li and the conductive material, which can result in the formation of cracks in the current collector, as will be explained in more detail herein below. The formation of cracks in the current collector is particularly likely when more desirable and thinner current collectors are used, and also when other deposition techniques involving the use of lithium at high temperatures are implemented.

[0007] The inventors are aware of the following documents: US2020 / 099039, WO2020 / 240553, WO2020 / 210913, WO2014 / 201569, US7,964,307B2, US2021 / 0218032A1, US11,437,624B2, WO2022 / 077120A1, and US2022 / 0328803. There remains a need for efficient and cost-effective methods to produce negative electrodes for lithium batteries, particularly methods that allow for Li deposition techniques other than PVD and that do not damage the current collector. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2020 / 099039 [Patent Document 2] International Publication No. 2020 / 240553 [Patent Document 3] International Publication No. 2020 / 210913 [Patent Document 4] International Publication No. 2014 / 201569 [Patent Document 5] U.S. Patent No. 7,964,307B2 [Patent Document 6] US Patent Application Publication No. 2021 / 0218032A1 [Patent Document 7] U.S. Patent No. 11,437,624B2 [Patent Document 8] International Publication No. 2022 / 077120A1 [Patent Document 9] US Patent Application Publication No. 2022 / 0328803 Summary of the Invention

[0009] The inventors have designed and implemented a method for producing an anode for a lithium battery. The method includes providing a current collector, forming a layer of protective material thereon, depositing a lithophilic material on the layer of protective material, and depositing a molten lithium material on the layer of lithophilic material. The lithophilic material and the molten lithium material subsequently react to form the anode active material. The current collector and / or at least one other layer of the anode may include a continuous 3D structure on its surface. The method may also include a plasma treatment that may lead to the formation of a lithophilic surface. The protective material deposited on the current collector constitutes a barrier between the current collector and the lithium in the anode active material, thus avoiding the formation of cracks in the current collector.

[0010] In an embodiment of the invention, deposition of the lithophilic material onto the protective layer is followed by a plasma treatment leading to a plasma treated lithophilic material prior to deposition of the molten lithium material.

[0011] In an embodiment of the invention, the protective layer is subjected to a plasma treatment leading to the formation of a lithophilic surface onto which molten lithium material is deposited.

[0012] The plasma treatment may be a thermal atmospheric plasma or any other suitable plasma treatment.

[0013] In an embodiment of the present invention, the current collector is provided with a continuous 3D structure formed on its surface. Furthermore, at least one other layer of the negative electrode, including the protective layer, the lithophilic surface, the layer of negative electrode active material, and the layer of surface treatment agent, may include a continuous 3D structure. This continuous 3D structure may be formed on its surface by electrochemical or chemical deposition of a conductive material. Alternatively, for example, with respect to the current collector, the continuous 3D structure may be formed by providing some roughness on its surface using techniques that may include mechanical and / or laser treatment, electrochemical oxidation, chemical etching, or any other suitable technique.

[0014] In an embodiment of the present invention, the lithium material in molten form comprises lithium or an alloy thereof.

[0015] In an embodiment of the invention, there is provided an anode comprising a current collector, a layer of protective material deposited on the current collector, and a layer of anode active material formed after reaction between a lithophilic material and a lithium material in molten form or formed after depositing a lithium material on the lithophilic surface. In an embodiment of the invention, the anode is single-sided or the anode is double-sided. In an embodiment of the invention, the current collector has a thickness of about 4 to about 5 μm.

[0016] In an embodiment of the invention, an apparatus is provided that is adapted to carry out the methods described herein to produce the anodes described herein.

[0017] In an embodiment of the present invention, the lithium battery is a lithium ion battery or an all-solid-state battery.

[0018] Thus, according to its aspects, the present invention provides: (1) A method for producing a negative electrode for a lithium battery, the method comprising: a) providing a current collector; b) depositing a layer of protective material on a surface of the current collector to obtain a protected current collector; c) depositing a layer of lithophilic material on a surface of the protected current collector; and d) depositing a layer of lithium material in molten form on the layer of lithophilic material, whereby the lithophilic material reacts with the molten lithium material to form a layer of negative electrode active material. (2) A method for producing a negative electrode for a lithium battery comprising: a) providing a current collector; b) depositing a layer of protective material on a surface of the current collector to obtain a protected current collector; c) depositing a layer of lithophilic material on the layer of protective material and then c1) subjecting the layer of lithophilic material to a plasma treatment to obtain a plasma-treated layer of lithophilic material; and d) depositing a layer of lithium material in molten form on the plasma-treated layer of lithophilic material, whereby the lithophilic material reacts with the molten lithium material to form a layer of negative electrode active material. (3) A method for producing a negative electrode for a lithium battery comprising: a) providing a current collector; b) depositing a layer of protective material on a surface of the current collector to obtain a protected current collector; c) subjecting the protected current collector to a plasma treatment to obtain a plasma-treated protected current collector having a lithophilic surface; and d) depositing a layer of lithium material in molten form on the lithophilic surface, thereby forming a layer of negative electrode active material. (4).a1) The method according to any one of (1) to (3) above, further comprising forming a continuous 3D structure on the surface of the current collector before performing step b), so as to obtain a textured current collector. (5).b1) A method according to any one of (1) to (4) above, further comprising forming a continuous 3D structure on the surface of the protected current collector before performing step c) or step c1), so as to obtain a textured protected current collector. (6). The method according to any one of (1) to (5) above, further comprising: e) depositing a layer of a surface treatment agent on the layer on which the negative electrode active material is formed. (7).d1) The method according to any one of (1) to (6) above, further comprising forming a continuous 3D structure on a surface of the negative electrode active material layer before performing step e). (8).e1) The method according to any one of (1) to (7) above, further comprising forming a continuous 3D structure on the surface of the surface treatment agent layer. (9) The method according to any one of (1) to (8) above, wherein steps a1), b), b1), c), c1), d), d1), e), and e1) are performed on both sides of a current collector to produce a double-sided negative electrode, and optionally steps a1), b), b1), c), c1), d), d1), e), and e1) are all performed on one side of the current collector and then all performed on the other side of the current collector, and optionally each of steps a1), b), b1), c), c1), d), d1), e), and e1) are performed simultaneously on one side of the collector and then simultaneously on the other side of the current collector. (10) The method according to any one of (1) to (9) above, wherein steps a1) and b1) each independently comprise electrochemical deposition of a conductive material onto a surface of the current collector or onto a surface of the protected current collector, and optionally the conductive material is the same material as the current collector, and optionally the conductive material is a different material from the current collector. (11) The method according to any one of (1) to (10) above, wherein steps a1) and b1) each independently comprise providing some roughness to the surface of the current collector or the surface of the protected current collector, and optionally steps a1) and b1) each independently comprise mechanical and / or laser treatment, electrochemical oxidation, chemical etching, or any other suitable technique. (12) The method according to any one of (1) to (11) above, wherein step b) comprises electrochemical deposition, electroless plating, or any other suitable technique. (13) The method according to any one of (1) to (12) above, wherein step c) comprises electrochemical oxidation or reduction, or any other suitable technique. (14) The method according to any one of (1) to (13) above, wherein the plasma treatment in step c1) is a thermal atmospheric pressure plasma. (15) The method according to any one of (1) to (14) above, wherein step d) comprises the use of a wet method, wave soldering, the use of a heated nozzle, an anilox roll, or any other suitable technique. (16) The method according to any one of (1) to (15) above, wherein at least one drying step is carried out after any one of steps a1), b), b1), c), d), and e). (17) The method according to any one of (1) to (16) above, wherein the lithium material in molten form is at a temperature of about 180°C to about 400°C, and optionally, the lithium material in molten form is at a temperature of about 210°C. (18) The method of any one of (1) to (17) above, wherein the current collector comprises a material that is Cu, Al, Ni, Ti, C, stainless steel, a conductive polymer, or a combination thereof, and optionally, the current collector comprises Cu, Al, or carbon-coated Al. (19) The method according to any one of (1) to (18) above, wherein the protective material comprises Ni, Co, Cr, Fe, Ti, or a combination thereof, and optionally, the protective material comprises Ni. (20) Lithophilic materials include CuO, Cu 2O, ZnO, MnO 2 , SnO 2 , Cu, Au, Mg, Al, In, B, Zn, Sn, Si, SiO 2 , SiO x , a metal fluoride, a metal boride, or a combination thereof, and optionally, the lithophilic material comprises ZnO, Zn, or Sn. (21) The method according to any one of (1) to (20) above, wherein the lithophilic surface has a 3D structure, and optionally, the lithophilic surface contains Ni. (22) The method according to any one of the above (1) to (21), wherein the lithium material in molten form comprises lithium or an alloy thereof, and optionally the lithium material in molten form is lithium metal, and optionally the lithium alloy is a binary alloy such as Li-Mg, Li-Al, Li-Na, Li-Si, Li-Sn, Li-Zn, Li-Ag, Li-K, Li-B, Li-In, or any other suitable lithium binary alloy, or the lithium alloy is a ternary alloy such as Li-Al-Na, Li-Mg-Na, Li-Al-Si, Li-Mg-Si, or a ternary alloy including elements such as Cu, Zn, Sn, Ca, Sr, or any other suitable lithium ternary alloy. (23) Surface treatment agents include Ag, Zn, Al, SiO x , Sn, Si, Li 2 CO 3 , LiF, carbon black, carbon nanofiber, graphene, or any other suitable surface treatment agent. (24) The method according to any one of (1) to (23) above, wherein the lithium battery is a lithium ion battery or an all-solid-state battery. (25) A negative electrode produced by the method defined in any one of (1) to (24) above. (26) A negative electrode for a lithium battery comprising: a current collector; a layer of protective material deposited on the current collector; and an active negative electrode material formed after reaction between a lithophilic material and a lithium material in molten form, optionally wherein the active negative electrode material is formed after depositing the lithium material on the lithophilic surface. (27) The negative electrode according to (25) or (26) above, wherein there is substantially no physical or chemical interaction between the current collector and the negative electrode active material. (28) The negative electrode according to any one of (25) to (27) above, which is one-sided or both-sided. (29) The negative electrode according to any one of (25) to (28) above, wherein the current collector has a thickness of about 4 to about 5 μm. (30) An apparatus adapted to produce a negative electrode as defined in any one of (25) to (29) above. (31) Use of a negative electrode as defined in any one of (25) to (29) above in the manufacture of a lithium battery. (32) A method for producing a lithium battery, comprising using a negative electrode as defined in any one of (25) to (29) above. (33) A lithium battery comprising a negative electrode as defined in any one of (25) to (29) above, optionally wherein the lithium battery is a lithium ion battery or an all-solid-state battery.

[0019] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments, given by way of example only with reference to the accompanying drawings.

[0020] The patent or application contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. [Brief description of the drawings]

[0021] In the accompanying drawings: [Figure 1] EDS analysis of a cross section of a sample consisting of a copper current collector foil covered with a 50 nm thick Zn coating as the lithophilic material and in contact with molten Li. A) SEM image of the cross section, B) EDS line scan analysis across the cross section as a function of depth. [Diagram 2] 1A and 1B are negative electrodes according to the present invention illustrating single-sided and double-sided negative electrodes. [Diagram 3] 13 shows the behavior of the copper foil on the backside of each sample as a function of time for Cu-Zn-Li and Cu-Ni-Zn-Li. [Figure 4] SEM and EDS analysis of the backside of Cu-Ni-Zn-Li and Cu-Zn-Li samples 30 seconds after contact with molten Li. [Diagram 5] Variation of the contact angle of molten Li on Cu-Ni substrates as well as Cu-Ni-Zn substrates with different Zn layer thicknesses. [Figure 6] Variation of the contact angle of molten Li on Cu-Ni-Zn substrates with different Zn layer thicknesses after 10 and 30 seconds of contact. [Figure 7] Variation of the contact angle of molten Li on Cu-Ni substrates, as well as Cu-Ni-Sn substrates with different Sn layer thicknesses. [Figure 8] Photographs of the surface of a Cu foil sample after Ni electrodeposition (a), ZnO electrodeposition (b), and Li coating (c). [Figure 9] Variation of contact angle for Cu-Ni and Cu-Ni-Sn (40 nm) with molten Li, and variation of contact angle for Cu-Ni-Sn (40 nm) with Li-Mg alloy. [Figure 10] FIG. 13 is an SEM image of a sample (after cryostructuring) showing a thin layer of Li with a thickness of 5 μm with good uniformity (variation less than ±1 μm). [Figure 11] FIG. 13 EDS line scan analysis across a cross section as a function of depth for a Cu-Ni-Sn-Li-Zn sample. [Figure 12]Lithophilic activity of different Cu-Ni substrates expressed as the total surface area of ​​molten Li after 2 min of diffusion time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Before the present invention is further described, it is to be understood that the present invention is not limited to the specific embodiments described below, since variations of these embodiments can be made and still fall within the scope of the appended claims. It is also to be understood that the terminology used is for the purpose of describing particular embodiments, and is not intended to be limiting. On the contrary, the scope of the present invention will be established by the appended claims.

[0023] In order to provide a clear and consistent understanding of the terms used herein, several definitions are provided below. Moreover, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0024] The use of the words "a" or "an," when used in conjunction with the term "comprising" in the claims and / or this specification, may mean "one," but this is also consistent with the meaning of "one or more," "at least one," and "one or more." Similarly, the word "another" may mean at least a second, or more.

[0025] As used in this specification and claim(s), the terms "comprising" (and any form of comprising, e.g., "comprise" and "comprises"), "having" (and any form of having, e.g., have and has), "including" (and any form of including, e.g., "includes" and "include"), or "containing" (and any form of containing, e.g., "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited, elements or process steps.

[0026] As used herein, the term "textured current collector" refers to a current collector having at least one surface with a continuous 3D structure formed thereon. The continuous 3D structure may be formed by electrochemical deposition of a conductive material or by techniques including mechanical and / or laser processing, electrochemical oxidation (decomposition), chemical etching, or any other suitable technique. It is noted that the term "textured" is also used herein in reference to any other layer of the negative electrode that includes a continuous 3D structure. Such layers are, for example, a protective layer, a layer of active negative electrode material, and a layer of a surface treatment.

[0027] As used herein, the term "lithophilic surface" refers to a surface that has an affinity for lithium. The surface may be a surface of a current collector having a protective material thereon. The surface may also include a continuous 3D structure. Lithophilic properties may be imparted to the surface upon plasma treatment.

[0028] The present inventors have designed and implemented a method for producing a negative electrode for a lithium battery.

[0029] Our data confirm that when molten Li metal is applied to a Cu or Al foil (even at a low temperature of 210° C.), the surface of the current collector metal starts to form an alloy, and when the applied layer of molten Li solidifies, fragments of the current collector material can be found inside or on the surface of the Li layer. Figure 1 shows an EDS analysis of a cross section of a sample composed of a copper current collector foil covered with a 50 nm thick Zn coating as a lithophilic material and in contact with molten Li. Figure 1A is an SEM image of the cross section, and Figure 1B corresponds to an EDS line scan analysis across the cross section as a function of depth. The Si signal is due to the resin used to prepare the sample for cryosectioning, and the detection of a C signal is a usual one in this type of analysis due to the inevitable presence of contamination. The signal from oxygen gives an idea of ​​where the top of the deposited Li layer starts (at about 1.4 μm) and where it ends (at about 4.8 μm). As can be seen, a very strong signal from copper was detected at the surface of the deposited Li layer, indicating that Cu fragments had detached from the Cu foil surface and formed intermetallic particles on top of the Li layer.

[0030] Note that in FIG. 2, reference numerals 1-5 identify elements of the negative electrode as follows: 1-current collector substrate, 2-textured layer, 3-protection layer, 4-Li material, and 5-surface treatment layer.

[0031] If the thickness of the current collector is too small, significant pores start to appear in the current collector material as a result of the interaction between the Li layer and the current collector surface, which can be a significant drawback, especially if the aim is to use very thin current collector foils (e.g., 4-5 μm) in order to minimize the manufacturing costs of the negative electrode and maximize the specific and volumetric energy densities of the battery.

[0032] It should be noted that different categories of lithophilic materials can be deposited on the barrier layer using electrochemical methods under controlled conditions (in terms of thickness and morphology of the deposition) in a time-effective and scalable electrochemical laboratory setup. Depending on the nature of the lithophilic material, at the stage of its deposition, the current collector can receive a cathodic current (becoming the cathode electrode during the lithophilic deposition) or an anodic current. Thus, the current collector can be a metal (such as elements Zn, Sn, Si, metal borides, or even ZnO, MnO 2 , or SnO 2 as a positive electrode (for the deposition of oxides such as CuO, Cu 2 O, SnO 2 , or MnO 2 The material can be used as a negative electrode (for depositing or forming a compound such as

[0033] The advantages of electrochemical deposition compared to other approaches are: -More cost-effective and much faster compared to PVD Compared to wet chemical and heat treatments, thickness is better controlled and more accurate, and the process is much faster (seconds or minutes instead of hours) It is easier to control the exact area where the lithophilic material is deposited, which in turn allows for better control of where the Li layer will be deposited · Scaling up of roll-to-roll electrochemical lithophilic deposition is easier and more cost-effective.

[0034] Example 1 Two sets of current collectors were prepared using 5μ thick copper foil. In one set, a 40 nm Zn layer was deposited on the copper foil in an electrolytic bath to prepare Cu-Zn foil samples. For the second set, a 300 nm Ni layer (thickness was estimated by using a quartz microbalance crystal) was electrochemically deposited prior to the deposition of the 40 nm Zn layer to prepare Cu-Ni-Zn foil samples. To evaluate the effect of the interaction between molten Li and Cu foil, the two sets of prepared samples were tested in the presence of a lithophilic material such as Zn by contacting them with the same amount of molten Li under the same conditions. Each test (less than 1 ppm H 2 O, O 2 and N 2 For the experiment, which was performed in an Ar glove box equipped with a purification unit to ensure uniformity of the sample, approximately 0.1 g of molten Li (prepared by heating Li to 250 °C in a stainless steel syringe and applied using a mechanically controlled piston) was placed on a sample holder (approximately 14 cm in diameter) that was capable of ensuring the flatness of the sample and controlling its temperature at approximately 230 °C. 2 The Li droplets were deposited on the surface of the samples (having a surface area of ​​100 nm). Once the Li droplets were deposited, they began to spread across the sample surface due to the lithophilic activity of the Zn layer. Each sample was allowed to contact with the molten Li droplet for a specific time interval (four were tested: 10 s, 30 s, 60 s, and 120 s), and then the samples were allowed to cool to room temperature.

[0035] Figure 3 shows the copper foil aspect on the backside of each sample. As can be seen, the Cu-Ni-Zn sample does not show any sign of being affected by contact with molten Li, regardless of the duration of contact. However, in the case of the Cu-Zn sample, even after 10 seconds of contact with molten Li, there is a visible sign of the appearance of a darker zone in the same area where Li was applied. After 30 seconds of contact, the area corresponding to the Li application shows a clear gray area on the backside in the case of Cu-Zn. Figure 4 shows an SEM image and EDS analysis of the backside of the Cu-Zn sample after 30 seconds of contact with Li. It can be observed that most of the Cu has been eroded and that Cu remains only as small clusters, rather than an intact foil. The effect of interaction with molten lithium becomes even more important after 60 and 120 seconds for the Cu-Zn-Li sample, as can be observed in Figure 3. As can be seen in Figures 3 and 4, the deposition of a Ni layer on the Cu foil sufficiently protects the Cu foil from its interaction with the molten Li.

[0036] Example 2 To evaluate the effect of the Zn layer thickness on its lithophilic properties, a 5 μm Cu foil (14 cm 2 Five square samples of 0.1 mm thick (0.01 mm thick) were electroplated with 300 nm of Ni followed by a Zn layer with thicknesses of 40, 60, 80, 100, or 150 nm. Using the same experimental setup described in Example 1, a controlled drop (0.1 g) of molten Li was deposited and the contact angle of the drop as a function of time was measured. Figure 5 shows the variation of the contact angle of molten Li on Cu-Ni substrates as well as Cu-Ni-Zn substrates with different Zn layer thicknesses.

[0037] As can be seen from FIG. 5, when the Cu foil is covered only with a protective layer of 300 nm of electrodeposited Ni, its surface does not show lithophilicity towards Li, with a measured contact angle of about 118° after 2 seconds. The contact angle reaches 112° after 120 seconds, remaining substantially unchanged. In contrast, electrodeposition of only 40 nm of Zn onto the Cu-Ni surface results in a much lower contact angle of 61° after 30 seconds, indicating the lithophilic effect of the Zn deposit. It can also be seen that increasing the thickness of the Zn deposit leads to even lower contact angle values. To better show the effect of Zn thickness on the lithophilic effect, the same data of FIG. 5 are presented in FIG. 6 for contact angle times of 10 and 30 seconds for different Cu-Ni-Zn samples. As can be seen, after 30 seconds of contact between molten Li and Cu-Ni-Zn with a Zn layer of 150 nm thickness, a contact angle value as low as 18° is obtained.

[0038] Example 3 To evaluate the lithophilic effect of Sn, a 5 μm Cu foil (14 cm 2 Three square samples of Zn and Zn-Zn alloys were electroplated with 300 nm of Ni followed by a Sn layer with a thickness of 40, 60, or 80 nm. Using the same experimental setup described in Example 1, a controlled drop (0.1 g) of molten Li was deposited and the contact angle of the drop was measured as a function of time. FIG. 7 shows the variation of the contact angle of molten Li on Cu-Ni substrates as well as Cu-Ni-Sn substrates with different Sn layer thicknesses. As in the case of Zn, the Cu-Ni-Sn samples also show a very good lithophilic effect when compared to Cu-Ni without lithophilic agent on the surface. In the case of Sn, all three samples of 40, 60, and 80 nm showed similar lithophilic activity, as can be observed in FIG. 7.

[0039] Example 4 To evaluate the lithophilic effect of ZnO, a Cu foil (14 cm) with a 300 nm electrodeposited Ni protective layer was 2 The Cu-Ni-ZnO samples were prepared by electrodepositing a thin layer of ZnO on a Cu-Ni-ZnO substrate using 0.1 M Zn(NO3 ) 2 The ZnO layer was electrodeposited by using a Cu-Ni foil as the positive electrode in an electrolytic cell containing the solution and a Zn plate as the negative electrode. The electrolytic process was carried out at 5 mA / cm 2 and at a temperature of 62° C. for a duration of 36 seconds. The thickness of the ZnO layer is estimated to be about 30 nm. The sample was then placed in a glove box similar to that described in Example 1 and heated to 250° C. on a heating plate. Li was then melted on the surface of the sample by placing a Li rod made of extruded Li. Once the Li was melted, a manually operated blade made of high temperature silicon was used to remove the excess Li. FIG. 8 shows the photographs of the surface of the Cu foil sample after Ni electrodeposition (a), ZnO electrodeposition (b), and Li application (c). As can be seen, the melted Li is deposited only on the areas covered by the electrodeposited ZnO, indicating the effectiveness of ZnO as a lithophilic material for the melted Li application.

[0040] Example 5 To evaluate the lithophilic effect of Sn using Li alloys, the same type of experiments described in Example 3 were carried out using Cu-Ni-Sn(40 nm) and Li-Mg alloys with weight ratios of Li:Mg between 90% and 10%. The contact angle variations of Cu-Ni and Cu-Ni-Sn(40 nm) with molten Li, as well as Cu-Ni-Sn(40 nm) with Li-Mg alloys, are presented in FIG. 9. As can be seen, the contact angle values ​​of Li-Mg(10%) on Sn(40 nm) are lower than that of Li on Sn(40 nm), but Sn(40 nm) still shows clear lithophilic activity towards Li-Mg(10%) when comparing its contact angle values ​​with those of Li on Cu-Ni without a Sn lithophilic layer.

[0041] Example 6 This example demonstrates the feasibility of using molten Li to apply a thin, uniform layer of Li onto a current collector, such as a 5 μm Cu foil (130 cm). 2 A sample of 1000 nm was electroplated with 300 nm of Ni followed by a Sn layer with a thickness of 40 nm. The sample was then applied manually at a constant speed of 2 cm / s to the top surface of an anilox roll partially immersed in a reservoir containing molten Li at a temperature of 260° C. The anilox roll had a length of 700 mm and a diameter of 19 mm. It presented inverted pyramidal features (20 pyramids per 25 mm) and a depth of about 400 μm per pyramid. An SEM image of the sample (after cryostructuring) is shown in FIG. 10. A thin layer of Li with a thickness of 5 μm with good uniformity (variation less than ±1 μm) was obtained.

[0042] Example 7 To demonstrate the feasibility of depositing a surface treatment layer on the deposited Li layer of the proposed Li anode material, a Cu-Ni-Sn-Li sample similar to the sample produced in Example 6 was DC sputtered. An average target of 50 nm of Zn was deposited by applying a DC current of 50 mA to a 99.9% pure Zn target using high purity Ar (grade 6.0, 99.9999%) under a vacuum of 0.008 mbar. Figure 11 shows an EDS analysis of a cross section of the sample. EDS line scan analysis across the cross section as a function of depth shows the presence of a copper current collector foil (not the overall thickness of 5 μm), a 3.5-4.0 μm Ni protective layer, a 0.5-3.5 μm Li layer (no Li signal is present in this EDS due to the very weak signal from Li), as well as a Zn layer on top of the Li layer.

[0043] Example 8 5μm Cu foil (14cm 2 Two square samples of 100 nm of Ni were electroplated with 300 nm of smooth Ni, followed by electrodeposition of a rough Ni layer with 3D effect. In contrast to the smooth Ni layer, this 3D layer was electroplated with 2000 mA / cm2 and a high current density of 15 C / cm 2 The electrodeposition is performed with a total charge of NiSO as the electrolyte. 4 , N.H. 4 Cl solution was used. One of the samples with Ni3D was then treated with non-thermal atmospheric pressure plasma using a plasma etching handheld plasma wand. The device has a power of 18 W and the sample was treated using a near-field module (for conductive materials) at a distance of 2 mm and at a speed of about 10 mm / s. Using the same experimental setup described in Example 1, a controlled drop of molten Li (0.1 g) was deposited on Cu-Ni and Cu-Ni-3DNi with and without plasma treatment. Due to the roughness of the Cu-Ni-3DNi samples and the rapid spreading of the molten Li droplet, it was very difficult to make a comparison of the lithophilic activity using contact angle parameters. In this case, the molten Li droplet was allowed to spread on the surface for 2 minutes and the total surface area of ​​the spread Li was measured and used as an indicator of the lithophilic activity of the substrate surface. The results are presented in Figure 12. As can be seen, the electrodeposition of rough 3D Ni on the substrate leads to an increase in the lithophilicity of the surface compared to a Cu foil covered only with a smooth Ni layer. The plasma treatment made it possible to further increase the lithophilicity of the Ni3D substrate.

[0044] As will be understood by those skilled in the art, the method according to the present invention comprises the following steps: a) providing a current collector, b) depositing a layer of protective material on the surface of the current collector, c) depositing a layer of lithophilic material on the layer of protective material, and d) depositing a layer of lithium material in molten form on the layer of lithophilic material, where the lithophilic material reacts with the molten lithium material to form the anode active material. In an embodiment of the present invention, the method comprises a subsequent step, namely e) depositing a layer of a surface treatment agent on the formed anode active material. In an embodiment of the present invention, step a1) of forming a continuous 3D structure on the surface of the current collector to obtain a textured current collector is performed before performing step b).

[0045] In an embodiment of the invention, step c) is followed by step c1), which is a plasma treatment of the lithophilic material to obtain a plasma-treated lithophilic material. Step d) is then performed. In another embodiment, step c) is completely replaced by step c1). In such an embodiment, the plasma treatment is performed on a protective layer leading to the formation of a lithophilic surface, preferably the protective layer comprises a continuous 3D structure and / or the protective layer comprises Ni. The plasma treatment may be a thermal atmospheric plasma or any other suitable plasma treatment.

[0046] In an embodiment of the present invention, the continuous 3D structure may be formed on the surface of the negative electrode active material layer and / or the surface of the surface treatment agent layer. Thus, step d1), i.e., forming the continuous 3D structure on the surface of the negative electrode active material layer, is performed immediately after step d), and / or step e1), i.e., forming the continuous 3D structure on the surface of the surface treatment agent layer, is performed immediately after step e).

[0047] The step of forming a continuous 3D structure on the surface of the current collector or on any other layer of the negative electrode to obtain a textured current collector may include providing some roughness to the surface of the current collector. This step may include mechanical and / or laser treatment, electrochemical oxidation, chemical etching, or any suitable technique known to a person skilled in the art. In an embodiment of the present invention, the continuous 3D structure may be imparted to the negative electrode active material layer and / or the surface treatment layer.

[0048] The step of depositing a layer of protective material on the surface of the current collector, i.e., step b), may comprise electrochemical deposition, electroless plating, or any other suitable technique known to those skilled in the art.

[0049] The step of depositing a layer of lithophilic material on the layer of protective material, i.e. step c), may involve electrochemical oxidation or reduction, or any other suitable technique known to a person skilled in the art.

[0050] The step of depositing a layer of lithium material in molten form onto the layer of lithophilic material or onto the lithophilic surface, i.e. step d), may involve infiltration, wave soldering, use of a heated nozzle, an anilox roll, or any other suitable technique.

[0051] As will be appreciated by those skilled in the art, the present invention also provides a negative electrode produced by the method according to the present invention. The negative electrode may be single-sided or double-sided. The negative electrode may have a thickness of about 4 to about 5 μm.

[0052] As will be appreciated by those skilled in the art, the present invention further provides an apparatus adapted to carry out the method of producing the negative electrode according to the present invention. The use of the negative electrode in the manufacture of a lithium battery, as well as a manufacturing method for producing a lithium battery including the use of the negative electrode, are also within the scope of the present invention. Furthermore, the present invention provides a lithium battery comprising the negative electrode. The lithium battery may be a lithium ion battery or an all-solid-state battery.

[0053] As will be appreciated by those skilled in the art, other variations and combinations may be made to the various embodiments of the invention as described hereinabove.

[0054] The scope of the claims should not be limited by the preferred embodiments described in the examples, but should be given the broadest interpretation consistent with the description as a whole.

[0055] This description refers to several documents, the contents of which are incorporated herein by reference in their entirety.

Claims

1. 1. A process for producing an anode for a lithium battery, comprising: a) providing a current collector; b) depositing a layer of protective material on the surface of said current collector to obtain a protected current collector; c) depositing a layer of lithophilic material on the surface of the protected current collector; d) depositing a layer of lithium material in molten form on the layer of parent lithium material, such that the parent lithium material reacts with the molten lithium material to form a layer of active anode material.

2. 1. A process for producing an anode for a lithium battery, comprising: a) providing a current collector; b) depositing a layer of protective material on the surface of said current collector to obtain a protected current collector; c) depositing a layer of lithophilic material on a surface of the protected current collector; and c1) subjecting the layer of lithophilic material to a plasma treatment to obtain a plasma-treated layer of lithophilic material. d) depositing a layer of lithium material in molten form on the layer of parent lithium material that has been subjected to plasma treatment, such that the parent lithium material reacts with the molten lithium material to form a layer of active anode material.

3. 1. A process for producing an anode for a lithium battery, comprising: a) providing a current collector; b) depositing a layer of protective material on the surface of said current collector to obtain a protected current collector; c1) subjecting the protected current collector to a plasma treatment to obtain a plasma-treated protected current collector having a lithophilic surface; d) depositing a layer of lithium material in molten form on said lithium-prone surface, thereby forming a layer of active anode material.

4. 10. The process of claim 1, further comprising forming a continuous 3D structure on a surface of the current collector before performing step a1) step b) to obtain a textured current collector.

5. The process described in claim 2, further comprising forming a continuous 3D structure on the surface of the current collector before performing step a1) step b) to obtain a textured current collector.

6. The process described in claim 3, further comprising forming a continuous 3D structure on the surface of the current collector before performing step a1) step b) to obtain a textured current collector.

7. 5. The process of claim 4, further comprising forming a continuous 3D structure on a surface of the protected current collector before performing step b1) step c) to obtain a textured protected current collector.

8. The process described in claim 5, further comprising forming a continuous 3D structure on the surface of the protected current collector before performing step b1) step c1) to obtain a textured protected current collector.

9. The process described in claim 6, further comprising forming a continuous 3D structure on the surface of the protected current collector before performing step b1) step c1) to obtain a textured protected current collector.

10. The process of claim 7, further comprising step e) depositing a layer of a surface treatment agent on the layer of formed active anode material.

11. The process of claim 8, further comprising step e) depositing a layer of a surface treatment agent on the formed layer of active anode material.

12. The process of claim 9, further comprising step e) depositing a layer of a surface treatment agent on the formed layer of active anode material.

13. 11. The process of claim 10, further comprising forming a continuous 3D structure on a surface of the layer of anode material before performing step d1) step e).

14. The process of claim 11, further comprising forming a continuous 3D structure on the surface of the layer of anode material before performing step d1) step e).

15. The process of claim 12, further comprising forming a continuous 3D structure on the surface of the layer of anode material before performing step d1) step e).

16. 14. The process of claim 13, further comprising step e1) forming a continuous 3D structure on the surface of the layer of surface treatment agent.

17. The process described in claim 14, further comprising step e1) forming a continuous 3D structure on the surface of the layer of surface treatment agent.

18. The process described in claim 15, further comprising step e1) forming a continuous 3D structure on the surface of the layer of surface treatment agent.

19. performing steps a1), b), b1), c), d), d1), e), and e1) on both sides of the current collector to produce a double-sided anode; optionally, steps a1), b), b1), c), d), d1), e), and e1) are all performed on one side of the current collector and then on the other side of the current collector; 17. The process of claim 16, wherein optionally each of steps a1), b), b1), c), d), d1), e), and e1) is performed simultaneously on one side of the current collector and then on the other side of the current collector.

20. Performing steps a1), b), b1), c), c1), d), d1), e), and e1) on both sides of the current collector to produce a double-sided anode; optionally, steps a1), b), b1), c), c1), d), d1), e), and e1) are all performed on one side of the current collector and then on the other side of the current collector; 20. The process of claim 17, wherein optionally each of steps a1), b), b1), c), c1), d), d1), e), and e1) is performed simultaneously on one side of the current collector and then on the other side of the current collector.

21. The method of claim 20, wherein steps a1), b), b1), c), c1), d), d1), e), and e1) are performed on both sides of the current collector to produce a double-sided anode; optionally, steps a1), b), b1), c), c1), d), d1), e), and e1) are all performed on one side of the current collector and then on the other side of the current collector; 20. The process of claim 18, wherein optionally each of steps a1), b), b1), c), c1), d), d1), e), and e1) is performed simultaneously on one side of the current collector and then on the other side of the current collector.

22. steps a1) and b1) each independently comprise electrochemically depositing a conductive material on the surface of the current collector or on the surface of the protected current collector; Optionally, the conductive material is the same material as the current collector; 22. The process of any one of claims 4 to 21, wherein optionally the conductive material is a different material from the current collector.

23. steps a1) and b1) each independently include providing a specified roughness on the surface of the current collector; 22. The process of any one of claims 4 to 21, wherein optionally steps a1) and b1) each independently comprise mechanical and / or laser treatment, electrochemical oxidation, chemical etching, or any suitable technique.

24. The process of any one of claims 1 to 21, wherein step b) comprises electrochemical deposition, electroless plating, or any suitable technique.

25. The process of any one of claims 1 to 21, wherein step c) comprises electrochemical oxidation or reduction, or any suitable technique.

26. 4. The process according to claim 2 or 3, wherein the plasma treatment of step c1) is a thermal plasma at atmospheric pressure.

27. The process of any one of claims 1 to 21, wherein step d) comprises an infiltration process, wave soldering, the use of a heated nozzle, the use of an anilox cylinder, or any suitable technique.

28. The process of any one of claims 4 to 21, wherein at least one drying step is performed after any one of steps a1), b), b1), c), d), and e).

29. the molten form of the lithium material is at a temperature of about 180°C to about 400°C; 22. The process of any one of claims 1 to 21, wherein optionally the lithium material in molten form is at a temperature of about 210°C.

30. the current collector comprises a material that is Cu, Al, Ni, Ti, C, stainless steel, a conductive polymer, or a combination thereof; 22. The process of any one of claims 1 to 21, optionally wherein the current collector comprises Cu, Al, or carbon-coated aluminum.

31. the protective material comprises Ni, Co, Cr, Fe, Ti, or a combination thereof; 22. The process of any one of claims 1 to 21, optionally wherein the protective material comprises Ni.

32. The lithium-philic material is CuO, Cu ２ O, ZnO, MnO ２ , SnO ２ , Cu, Au, Mg, Al, In, B, Zn, Sn, Si, SiO ２ , SiO ｘ , a metal fluoride, a metal boride, or a combination thereof; 22. The process of any one of claims 1 to 21, optionally wherein the parent lithium material comprises ZnO, Zn, or Sn.

33. the lithophilic surface has a continuous 3D structure; 22. The process of any one of claims 1 to 21, optionally wherein the lithophilic surface comprises Ni.

34. the molten form of the lithium material comprises lithium or an alloy thereof; Optionally, the molten form of the lithium material is lithium metal; 22. The process of any one of claims 1 to 21, wherein optionally the lithium alloy is a binary alloy, such as Li—Mg, Li—AI, Li—Na, Li—Si, Li—Sn, Li—Zn, Li—Ag, Li—K, Li—B, or any other suitable binary lithium alloy, or the lithium alloy is a ternary alloy, such as Li—AI—Na, Li—Mg—Na, Li—AI—Si, Li—Mg—Si, or a ternary alloy comprising elements such as Cu, Zn, Sn, Ca, Sr, or any other suitable ternary lithium alloy.

35. The surface treatment agent contains Ag, Zn, SiO ｘ , Sn, Si, Li ２ CO ３ , LiF, carbon black, carbon nanofibers, graphene, or any other suitable surface treatment.

36. 22. The process of any one of claims 1 to 21, wherein the lithium battery is a lithium ion battery or an all-solid-state battery.

37. An anode produced by the process of any one of claims 1 to 21.

38. 1. An anode for a lithium battery, comprising: A current collector; a layer of protective material deposited on the current collector; an active anode material formed as a result of a reaction between a parent lithium material and a lithium material in molten form; Optionally, an anode wherein said active anode material is formed by depositing said lithium material onto a lithium-parent surface.

39. 40. The anode of claim 38, wherein there is substantially no physical or chemical interaction between the current collector and the active anode material.

40. 39. The anode of claim 38, which is single-sided or double-sided.

41. 39. The anode of claim 38, wherein the current collector has a thickness of about 4 μm to about 5 μm.

42. Apparatus adapted for manufacturing an anode according to any one of claims 38 to 41.

43. Use of an anode according to any one of claims 38 to 41 in the production of a lithium battery.

44. A process for producing a lithium battery comprising the use of an anode according to any one of claims 38 to 41.

45. A lithium battery comprising the anode according to any one of claims 38 to 41, Optionally, the lithium battery is a lithium ion battery or an all-solid-state battery.

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