A functional patterned pole piece, a preparation method and use thereof

Abstract

The application belongs to the technical field of batteries, and provides a functional patterned pole piece, a preparation method and use thereof. The recess bottom and sidewall of the functional patterned pole piece are provided with an interface stabilizing functional layer. The composition of the interface stabilizing functional layer comprises an oligomeric copolymer containing an ethylene carbonate structural unit. The oligomeric copolymer with a characteristic functional group structural unit having a film-forming additive function forms a film in the recess, can preferentially react with electrolyte during the first charging (formation) of the battery, is beneficial to forming a stable interface film rich in LiF on the inner surface of the recess, can realize the point inhibition of side reactions and micro-crack propagation in the high stress area at the root of the recess, and thus effectively improves the cycle performance and long-term stability of the pole piece. Moreover, the interface stabilizing functional layer is arranged on the inner surface of the recess, does not affect the liquid guiding / liquid storing function, and is beneficial to taking into account the energy density of the whole pole piece.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a functional patterned electrode sheet, its preparation method and application. Background Technology

[0002] During cycling, the surface of the active material layer in lithium-ion battery electrodes undergoes volume expansion and contraction, leading to stress within the coating. Especially when the electrode surface has an embossed groove structure, the root of the groove (the bottom and its junction with the sidewall) becomes a stress concentration area, prone to developing microcracks during long-term cycling. Once microcracks form and propagate, they cause the following chain of problems: (a) electrolyte seeps into the coating along the cracks, accelerating side reactions between the active material and the electrolyte; (b) the SEI (solid electrolyte interface) film in the cracked area continuously ruptures and regenerates, continuously consuming active lithium and electrolyte; (c) crack propagation eventually leads to the shedding of the active layer, resulting in a sharp decline in battery capacity. Summary of the Invention

[0003] In view of the problems existing in the prior art, the purpose of this invention is to provide a functional patterned electrode, its preparation method, and its uses. This functional patterned electrode has an interface stabilizing functional layer disposed on the bottom and sidewalls of the grooves on the patterned surface. The interface stabilizing functional layer comprises an oligomeric copolymer containing ethylene carbonate structural units. These ethylene carbonate structural units enable the oligomeric copolymer to possess electrochemical activity as a film-forming additive, allowing it to preferentially react with the electrolyte during the first charge (formation) of the battery. This forms a stable interface film rich in LiF on the inner surface of the groove, thereby specifically suppressing side reactions and microcrack propagation in the high-stress region at the root of the groove, effectively improving the cycle performance and long-term stability of the electrode. Furthermore, since the interface stabilizing functional layer is disposed on the inner surface of the groove, it does not affect the electrolyte conduction / storage function and helps maintain the overall energy density of the electrode.

[0004] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a functional patterned electrode, comprising a current collector and an active layer disposed on at least one side of the current collector; the active layer having a patterned surface on the side away from the current collector; the patterned surface comprising grooves and protrusions; an interface stabilizing functional layer disposed on the bottom and sidewall surfaces of the grooves; the interface stabilizing functional layer comprising an oligomeric copolymer containing ethylene carbonate structural units.

[0005] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0006] As a preferred embodiment of the present invention, the interface stabilization functional layer is not provided on the top surface of the protrusion and / or on the non-patterned surfaces of the active layer other than the patterned surface.

[0007] As a preferred embodiment of the present invention, the depth of the groove is 5% to 40% of the thickness of the active layer.

[0008] Preferably, the depth of the groove is 1μm to 50μm.

[0009] Preferably, the width of the groove is 50μm to 500μm.

[0010] As a preferred embodiment of the present invention, the thickness of the interface stabilizing functional layer is 5% to 15% of the depth of the groove.

[0011] Preferably, the mass of the interface stabilizing functional layer accounts for 0.01% to 0.5% of the mass of the active layer.

[0012] As a preferred embodiment of the present invention, the raw materials for forming the oligomeric copolymer include monomers and crosslinking agents, both having polymerizable unsaturated bonds; and the monomers include cyclic carbonates corresponding to the ethylene carbonate structural units, and / or the crosslinking agents contain the ethylene carbonate structural units.

[0013] As a preferred embodiment of the present invention, when the monomer includes the cyclic carbonate, the cyclic carbonate is a film-forming additive, and the film-forming additive includes VC (ethylene carbonate) and / or VEC (ethylene ethylene carbonate).

[0014] Preferably, when the monomer is not the cyclic carbonate, the monomer includes acrylate.

[0015] Preferably, when the crosslinking agent contains the ethylene carbonate structural unit, the crosslinking agent comprises a polyvinyl carbonate oligomer.

[0016] Preferably, when the crosslinking agent does not contain the ethylene carbonate structural unit, the crosslinking agent comprises polyethylene glycol diacrylate.

[0017] As a preferred embodiment of the present invention, the molecular weight of the oligomeric copolymer is 200 Da to 6000 Da.

[0018] As a preferred embodiment of the present invention, the interface stabilization functional layer further includes a first adhesive.

[0019] Preferably, the first adhesive comprises PVDF; and / or, based on the mass of the interface stabilizing functional layer as 100%, the proportion of the first adhesive is 5% to 30%.

[0020] Secondly, the present invention provides a method for preparing a functional patterned electrode sheet, comprising the following steps: A patterned electrode is provided, the patterned electrode comprising a current collector and an active layer disposed on at least one side of the current collector; the active layer having a patterned surface on the side away from the current collector; the patterned surface comprising grooves and protrusions; An oligomeric copolymer is provided, the oligomeric copolymer containing ethylene carbonate structural units; the oligomeric copolymer is prepared with a first solvent to form a functional layer solution; The functional layer solution is coated on one side of the patterned electrode with the patterned surface, while a negative pressure suction process is performed on the other side of the patterned electrode to allow the functional layer solution to enter and remain in the groove. The first solvent is removed by drying, and an interface-stabilizing functional layer is formed on the bottom and sidewall surfaces of the groove to obtain a functional patterned electrode.

[0021] As a preferred embodiment of the present invention, the preparation method satisfies at least one of the following conditions: Preferably, the first solvent comprises dimethyl carbonate (DMC).

[0022] Preferably, the mass percentage concentration of the oligomeric copolymer in the functional layer solution is 0.5% to 5%.

[0023] Preferably, the coating method includes spraying.

[0024] Preferably, the amount of the functional layer solution used is 1 to 2 times the total volume of the groove.

[0025] Preferably, the negative pressure of the negative pressure suction treatment is -0.01MPa to -0.1MPa.

[0026] Preferably, the negative pressure suction process is performed through a negative pressure suction nozzle, and the distance between the negative pressure suction nozzle and the surface of the patterned electrode is ≤0.05mm.

[0027] Preferably, in the negative pressure suction process, each groove corresponds to at least one negative pressure nozzle, or each negative pressure nozzle corresponds to at least one groove.

[0028] Preferably, the drying temperature is 40℃~80℃ and the drying time is 5min~20min.

[0029] As a preferred technical solution of the present invention, the method for preparing the oligomeric copolymer includes: The invention provides monomers and crosslinking agents, both having polymerizable unsaturated bonds; wherein the monomers include cyclic carbonates corresponding to the ethylene carbonate structural units, and / or the crosslinking agents contain the ethylene carbonate structural units; The monomer, crosslinking agent, initiator, chain transfer agent and second solvent are mixed and polymerized to obtain an oligomeric copolymer.

[0030] As a preferred embodiment of the present invention, the polymerization reaction temperature is 50℃~80℃.

[0031] Preferably, the initiator comprises azobisisobutyronitrile (AIBN).

[0032] Preferably, the amount of the initiator is 0.5% to 2% of the mass of the monomer.

[0033] Preferably, the chain transfer agent comprises dodecyl mercaptan (DDT).

[0034] Preferably, the chain transfer agent is used in an amount of 1% to 5% of the mass of the monomer.

[0035] Preferably, the second solvent comprises dimethyl carbonate.

[0036] Thirdly, the present invention provides a battery comprising the functional patterned electrode sheet described in the first aspect, or comprising the functional patterned electrode sheet obtained by the preparation method described in the second aspect.

[0037] Compared with existing technical solutions, the present invention has at least the following beneficial effects: The functional patterned electrode provided by this invention features an interface stabilizing layer on the bottom and sidewalls of the grooves on the patterned surface. This layer comprises an oligomeric copolymer containing electrochemically active ethylene carbonate structural units. This oligomeric copolymer functions as a film-forming additive, preferentially reacting with the electrolyte during the first charge (formation) of the battery. This forms a stable LiF-rich interface film on the inner surface of the groove, effectively suppressing side reactions and microcrack propagation in the high-stress region at the root of the groove, thus significantly improving the electrode's cycle performance and long-term stability. Since the interface stabilizing layer is located on the inner surface of the groove, it does not affect the electrolyte conduction / storage function and helps maintain the overall energy density of the electrode.

[0038] The method for preparing functional patterned electrodes provided by this invention achieves selective coating through a "coating + negative pressure suction and guidance" process. During coating, the airflow generated by the negative pressure on the back side guides the airflow to preferentially pass through the thinner groove region. Simultaneously, droplets of the functional layer solution on the non-patterned surface and the raised top surface are blown to adjacent grooves or directly extracted. Meanwhile, the solution within the grooves is retained due to capillary action, which facilitates selective deposition. By further controlling the coating amount of the functional layer solution, it can be ensured that the interface is stable and the functional layer is formed only on the inner surface of the grooves. Furthermore, this preparation method has good manufacturing compatibility; it can be implemented on the basis of existing embossing processes by only adding coating, negative pressure suction, and drying steps without changing the electrode body manufacturing process, making it suitable for large-scale implementation. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a cross-section of the functional patterned electrode sheet provided in Embodiment 1.

[0040] Figure 2 This is a schematic diagram of the spraying and negative pressure suction treatment in the preparation method of the functional patterned electrode sheet in Example 1.

[0041] In the diagram: 1-current collector, 2-active layer, 3-groove, 4-protrusion, 5-interface stabilizing functional layer, 6-atomizing nozzle, 7-negative pressure suction nozzle, 8-vacuum pump. Detailed Implementation

[0042] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0043] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0044] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0045] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0046] In this invention, the order in which the steps are written in the methods described in the various embodiments does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any conflict-free order, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0047] In existing technologies, patterning using conventional embossing processes results in purely physical embossing structures without any targeted functionalization. In particular, the root region of the grooves formed by patterning is prone to microcracks and side reactions during cycling, reducing the long-term cycling reliability of the electrode and even causing the active layer to detach. To address this, the field employs a solution of coating or impregnating the entire electrode surface to form a self-healing functional layer. However, covering the entire electrode surface with a self-healing layer inevitably increases the total thickness, sacrificing energy density. Furthermore, the large-area contact between the self-healing material and the electrolyte may trigger unnecessary side reactions. Moreover, the precision and controllability of full-surface coating and overall impregnation are not high; while covering the entire electrode, the self-healing layer may partially or completely fill the grooves, thus losing the original electrolyte conduction / storage function of the grooves.

[0048] To this end, the present invention provides a functional patterned electrode in one or more embodiments, comprising a current collector and an active layer disposed on at least one side of the current collector; the active layer has a patterned surface on the side away from the current collector; the patterned surface includes grooves and protrusions; an interface stabilizing functional layer is disposed on the bottom and sidewall surfaces of the grooves; the component of the interface stabilizing functional layer comprises an oligomeric copolymer containing ethylene carbonate structural units.

[0049] In the functional patterned electrode provided by this invention, an interface-stabilizing functional layer is formed on the inner surface of the groove, namely the bottom and sidewalls. This functional layer contains an oligomeric copolymer with ethylene carbonate structural units. The ethylene carbonate structural units are equivalent to integrating the functions of cyclic carbonate film-forming additives, or in other words, the oligomeric copolymer has characteristic functional group structural units with film-forming additive functions. This allows it to preferentially react with the electrolyte during the first charge (formation) of the battery, thereby forming a stable interface film rich in LiF on the inner surface of the groove. This effectively suppresses side reactions and microcrack propagation in the high-stress area at the root of the groove, thus improving the cycle performance and long-term stability of the electrode.

[0050] In some embodiments, the interface stabilizing functional layer is not disposed on the top surface of the protrusion and / or on the non-patterned surfaces (collectively referred to as flat surfaces) of the active layer other than the patterned surface. Thus, the interface stabilizing functional layer is only disposed on the inner surface of the groove, does not affect the liquid conduction / storage function, and is beneficial for maintaining the overall energy density of the electrode.

[0051] In some embodiments, the depth of the groove is 5% to 40% of the thickness of the active layer. For example, it can be 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, etc.

[0052] In some embodiments, the thickness of the interface-stabilizing functional layer is 5% to 15% (i.e., 1 / 20 to 1 / 7) of the depth of the groove. Exemplarily, it can be 5%, 8%, 10%, 12%, 13%, 14%, or 15%, preferably 1 / 15 to 1 / 10. This means the groove does not penetrate the active layer; the bottom and sidewalls of the groove still belong to the active layer material. As a further example, the thickness of the interface-stabilizing functional layer can be observed using a scanning electron microscope on the electrode cross-section. The boundary of the material contrast difference between the functional layer and the active material layer can be identified at the inner wall of the groove, and the distance from this boundary to the inner surface of the groove is the thickness of the functional layer. If the cross-section is uniformly prepared, in-situ AFM (atomic force microscopy) profilometry of the groove area can also be used for measurement.

[0053] In some embodiments, the mass of the interface stabilizing functional layer accounts for 0.01% to 0.5% of the mass of the active layer. For example, it may be 0.01%, 0.03%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.45%, or 0.5%, etc.

[0054] The interface stabilizing functional layer of the present invention is located only on the inner surface of the groove, and its thickness is controlled to be only 5% to 15% of the groove depth to form a thin layer design. When the mass ratio is only 0.01% to 0.5% of the active layer, it is more conducive to the complete preservation of the main space of the groove, so that its liquid guiding / storage function is not affected, and the impact on energy density can be controlled to a negligible level. This is conducive to balancing the functions of the groove and the interface stabilizing functional layer and the overall performance of the electrode.

[0055] It should be noted that the patterning of the active layer surface in this invention can be achieved through processes such as embossing. The resulting patterned surface has several grooves and protrusions, and the orthogonal projection of the grooves and protrusions onto the current collector forms a specific pattern. The arrangement of the grooves and protrusions can be periodic and / or have specific shapes, sizes, and extension directions. This invention does not limit the content of the grooves and protrusions; any widely used or theoretically applicable patterning design can be applied to this invention.

[0056] In some embodiments, the raw materials forming the oligomeric copolymer include monomers and crosslinking agents, both having polymerizable unsaturated bonds; and the monomers include cyclic carbonates corresponding to the ethylene carbonate structural units, and / or the crosslinking agent contains the ethylene carbonate structural units.

[0057] In some embodiments, when the monomer comprises the cyclic carbonate, the cyclic carbonate is a film-forming additive, and the film-forming additive comprises VC (ethylene carbonate) and / or VEC (4-vinyl-1,3-dioxolane-2-one).

[0058] In some embodiments, when the monomer is not the cyclic carbonate, the monomer comprises an acrylate.

[0059] In some embodiments, when the crosslinking agent contains the ethylene carbonate structural unit, the crosslinking agent comprises a polyvinyl carbonate oligomer.

[0060] In some embodiments, when the crosslinking agent does not contain the ethylene carbonate structural unit, the crosslinking agent comprises polyethylene glycol diacrylate (PEGDA).

[0061] In this invention, both the monomer and the crosslinking agent contain polymerizable unsaturated bonds to support the formation of oligomeric copolymers through processes such as chemical grafting and free radical polymerization. These polymerizable unsaturated bonds may include double bonds. At least one of the monomer and the crosslinking agent also contains a ethylene carbonate structure that can act as a film-forming additive, thereby enabling the oligomeric copolymer to carry ethylene carbonate structural units and possess electrochemical activity, thus allowing it to react in an electrolyte to form a stable interfacial film. Generally, the monomer refers to the unpolymerized substance, and the crosslinking agent refers to the oligomer / prepolymer. Therefore, when the monomer has a ethylene carbonate structure, it means that it belongs to the class of cyclic carbonates and has a ethylene carbonate structure, such as film-forming additives VC and / or VEC; the crosslinking agent can be an oligomer / prepolymer formed from a polymerizable cyclic carbonate film-forming additive, such as a polyvinyl carbonate oligomer formed from VC.

[0062] In some embodiments, the method for preparing the oligomeric copolymer includes: The invention provides monomers and crosslinking agents, both having polymerizable unsaturated bonds; wherein the monomers include cyclic carbonates corresponding to the ethylene carbonate structural units, and / or the crosslinking agents contain the ethylene carbonate structural units; The monomer, crosslinking agent, initiator, chain transfer agent and second solvent are mixed and polymerized to obtain an oligomeric copolymer.

[0063] In some embodiments, the polymerization reaction temperature is 50°C to 80°C, for example, it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, preferably 60°C to 70°C.

[0064] In some embodiments, the initiator includes azobisisobutyronitrile (AIBN).

[0065] In some embodiments, the initiator is used in an amount of 0.5% to 2% of the monomer by mass. For example, it may be 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8%, or 2%.

[0066] In some embodiments, the chain transfer agent includes dodecyl mercaptan (DDT).

[0067] In some embodiments, the chain transfer agent is used in an amount of 1% to 5% of the monomer by mass. For example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0068] In some embodiments, the second solvent includes dimethyl carbonate (DMC).

[0069] When preparing oligomeric copolymers, the molecular weight can be controlled by a chain transfer agent. After the reaction is complete, the precipitate is purified and dried to obtain the oligomeric copolymer.

[0070] In some embodiments, the molecular weight of the oligomeric copolymer is 200 Da to 6000 Da. Exemplarily, it can be 200 Da, 500 Da, 800 Da, 1000 Da, 2000 Da, 3000 Da, 4000 Da, 5000 Da, or 6000 Da, preferably 500 Da to 3000 Da; the molecular weight index of the present invention is the average molecular weight. The present invention controls the copolymer to be oligomeric, with a molecular weight of 200 Da to 6000 Da, which supports its good solubility in solvents (such as DMC), allowing it to be formulated into a uniform, low-viscosity solution, which is beneficial for coating (especially spray atomization) and uniform spreading within the groove. If the molecular weight is too high (e.g., >10000 Da), the solution viscosity is too high, the atomization effect is poor, and it is not conducive to film formation within the groove. Meanwhile, during the initial charging (formation) of this oligomeric copolymer, due to its short molecular chain and high proportion of end groups, it exhibits high reactivity and preferentially undergoes ring-opening decomposition at approximately 1.0V to 1.5V, participating in SEI film formation. When the molecular weight is too low (e.g., <200Da), the oligomer's volatility and loss rate are high, leading to decreased film-forming efficiency; when the molecular weight is too high (e.g., >6000Da), electrochemical activity decreases. Therefore, this invention preferably uses an oligomeric copolymer with a molecular weight of 500Da to 3000Da to achieve a balance between solubility, processability, and film-forming activity.

[0071] In some embodiments, the interface stabilizing functional layer further includes a first adhesive.

[0072] In some embodiments, the first binder comprises PVDF; and / or, based on 100% of the mass of the interface-stabilizing functional layer, the proportion of the first binder is 5% to 30%. Exemplarily, it can be 5%, 8%, 10%, 15%, 20%, 25%, or 30%, etc. An appropriate binder can improve the bond strength between the interface-stabilizing functional layer and the active layer. Too low a content results in insignificant bonding enhancement, while too high a content may mask the electrochemical activity of the cyclic carbonate functional groups, reducing the efficiency of interface film formation.

[0073] It should also be noted that, taking an oligomeric copolymer containing ethylene carbonate structural units prepared using VC and / or VEC as raw materials as an example, during the initial charging (formation), the oligomeric copolymer preferentially undergoes ring-opening polymerization and partial decomposition at approximately 1.0V~1.5V (vs. Li / Li+), releasing active substances to participate in the formation of a LiF-rich SEI film. The bottom layer of the formed interfacial film (immediately adjacent to the active material side) is rich in LiF and a cross-linked network of the oligomeric copolymer, while the outer layer is a conventional SEI component derived from the electrolyte. At this time, the original oligomeric copolymer skeleton is retained and, together with the decomposition products, constitutes an organic-inorganic composite interfacial layer.

[0074] In one or more embodiments of the present invention, a method for preparing a functional patterned electrode sheet is provided, comprising the following steps: A patterned electrode is provided, the patterned electrode comprising a current collector and an active layer disposed on at least one side of the current collector; the active layer having a patterned surface on the side away from the current collector; the patterned surface comprising grooves and protrusions; An oligomeric copolymer is provided, the oligomeric copolymer containing ethylene carbonate structural units; the oligomeric copolymer is prepared with a first solvent to form a functional layer solution; The functional layer solution is coated on one side of the patterned electrode with the patterned surface, while a negative pressure suction process is performed on the other side of the patterned electrode to allow the functional layer solution to enter and remain in the groove. The first solvent is removed by drying, and an interface-stabilizing functional layer is formed on the bottom and sidewall surfaces of the groove to obtain a functional patterned electrode.

[0075] The preparation method of this invention provides a selective coating process of "coating + negative pressure suction guidance". Its core principle is: utilizing the guiding effect of airflow generated by the negative pressure on the back side, the airflow preferentially passes through the thinner groove region, while simultaneously blowing droplets on the flat surface to adjacent grooves or directly removing them. Meanwhile, the solution within the grooves is retained due to capillary action, thereby achieving selective deposition. The preparation method of the functional patterned electrode provided by this invention has good manufacturing compatibility. It can be based on the existing embossing process, only adding coating, negative pressure suction, and drying steps, without changing the electrode body manufacturing process.

[0076] In some embodiments, the preparation method satisfies at least one of the following conditions: In some embodiments, the first solvent includes dimethyl carbonate (DMC).

[0077] In some embodiments, the mass percentage concentration of the oligomeric copolymer in the functional layer solution is 0.5% to 5%. Exemplarily, it can be 0.5%, 1%, 2%, 3%, 4%, or 5%, etc. The content of the oligomeric copolymer in the droplets after coating can be controlled by the concentration of the functional layer solution. If the concentration is too low, the deposition amount in a single spray is insufficient, requiring multiple sprays or extended spraying time; if the concentration is too high, the solution viscosity increases, the atomization effect deteriorates, and the droplet size becomes too large, which is not conducive to uniform spreading within the groove. A suitable concentration range can balance deposition efficiency and coating uniformity.

[0078] In some embodiments, the coating method includes spraying. Further spraying may utilize an atomizing nozzle to spray the functional layer solution in an atomized form.

[0079] In some embodiments, the amount of the functional layer solution is 1 to 2 times the total volume of the groove. Exemplarily, it can be 1, 1.2, 1.4, 1.5, 1.6, 1.8, or 2 times, preferably 1.2 to 1.5 times. Precise control of the applied functional layer solution facilitates its combination with negative pressure suction, ensuring sufficient retention of the functional layer solution within the groove. The remaining solution, being relatively small, can be guided by airflow into the groove or removed from the surface on flat surfaces and raised tops. That is, through airflow guidance, groove capillary action, and precise control of the solution amount, it is ensured that flat surfaces are free of excess coverage. Simultaneously, because the total amount of sprayed solution is controlled and excess solution is continuously suctioned out by negative pressure, the groove will not be filled, which is beneficial for forming a thin layer.

[0080] In some embodiments, the negative pressure suction process is performed using a negative pressure suction nozzle, the distance between the nozzle and the surface of the patterned electrode being ≤0.05mm. Exemplarily, this distance can be 0.05mm, 0.04mm, 0.03mm, 0.02mm, 0.01mm, or 0mm (i.e., adhered to the electrode surface, especially the current collector surface). Further, distance control can be achieved using a vacuum suction plate in conjunction with a sealing ring.

[0081] In some embodiments, during the negative pressure suction process, each groove corresponds to at least one negative pressure nozzle, or each negative pressure nozzle corresponds to at least one groove. Furthermore, the negative pressure nozzle can be connected to a device such as a vacuum pump to achieve negative pressure suction.

[0082] Furthermore, in order to better cover the functional layer solution at both the bottom and sidewalls of the groove, the size of the negative pressure nozzle is preferably controlled to be greater than or equal to the width of the groove. In some embodiments, when the size of the negative pressure nozzle is smaller than the width of the groove and the amount of functional layer solution is small, it is possible to form an interface-stabilized functional layer only at the bottom of the groove. However, since the sidewall is not covered, the root of the sidewall (the junction of the bottom and the sidewall) is still exposed to the electrolyte, and microcracks will still start from the root of the sidewall, resulting in limited improvement in the shedding rate.

[0083] In some embodiments, the negative pressure (vacuum degree) of the negative pressure suction treatment is -0.01MPa to -0.1MPa. For example, it can be -0.01MPa, -0.03MPa, -0.05MPa, -0.06MPa, -0.08MPa, or -0.1MPa, etc. The magnitude of the negative pressure is related to the depth-to-width ratio of the groove, the surface tension of the solution, and the air permeability of the electrode. For example, the deeper the groove and the greater the surface tension of the solution, the higher the required negative pressure; the greater the air permeability of the current collector, the lower the required negative pressure. The specific value can be adjusted according to the actual situation, and a suitable value can also be obtained through preliminary experiments.

[0084] This invention does not limit the specific patterned design of the grooves and protrusions, but when the grooves have a more suitable width and depth (i.e., a more suitable aspect ratio), it is beneficial for negative pressure suction treatment so that the functional layer solution can smoothly enter and be retained in the grooves, and it is also beneficial for the subsequent drying and evaporation of the solvent.

[0085] For example, in some embodiments, the depth of the groove is 1 μm to 50 μm. For example, it can be 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm, preferably 5 μm to 40 μm. In some embodiments, the width of the groove is 50 μm to 500 μm. For example, it can be 50 μm, 60 μm, 80 μm, 100 μm, 130 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, or 500 μm, preferably 100 μm to 300 μm.

[0086] It should also be noted that the negative pressure extraction process described in this invention does not depend on the permeability of the current collector itself. Although industrial current collectors (such as copper foil / aluminum foil) are macroscopically dense, they still contain submicron-level pinholes or grain boundary defects. More importantly, the solvent vapor in the functional layer solution and the trace amounts of gas remaining inside the electrode can form a weak airflow that penetrates the defects in the current collector under negative pressure, which is sufficient to guide droplets to deposit directionally within the groove. Furthermore, when a negative pressure scheme is used on the back of the electrode, the airflow can enter from the edge of the electrode and the lateral micropores of the active material layer, penetrate the weak area of ​​the active material layer at the bottom of the groove, and then be extracted, forming a lateral + longitudinal composite airflow, thereby achieving selective extraction in the groove area.

[0087] It should also be noted that when the interface stabilizing functional layer is applied to both sides of the electrode (referred to here as the A side and B side), after the A side has already undergone negative pressure suction treatment and dried to form the interface stabilizing functional layer, applying coating (such as spraying with an atomizing nozzle) and then negative pressure suction treatment to the B side will not cause adverse effects such as peeling of the interface stabilizing functional layer already formed on the A side. This is because the airflow direction generated by negative pressure suction is B side groove → active layer → current collector → negative pressure suction nozzle. The airflow path passes through the B side groove area, while the functional layer on the A side is located on the back side of the airflow path and is not directly impacted by the airflow. At the same time, the negative pressure applied by the negative pressure suction nozzle is -0.01MPa to -0.1MPa, and the gentle vacuum is insufficient to damage the adhesion between the cured interface stabilizing functional layer and the active layer. Furthermore, the interface stabilizing functional layer is further strengthened by the presence of binders such as PVDF. Furthermore, if necessary, a shielding or buffering structure, mechanism, or component corresponding to the cured functional layer on side A can be optionally provided on the negative pressure nozzle to further reduce the impact.

[0088] In some embodiments, the drying temperature is 40°C to 80°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C; the drying time is 5 min to 20 min, for example, 5 min, 6 min, 8 min, 10 min, 13 min, 15 min, 18 min, or 20 min.

[0089] In one or more embodiments of the present invention, a battery is provided, comprising the functional patterned electrode sheet described in the above embodiments, or comprising the functional patterned electrode sheet obtained by the preparation method described in the above embodiments.

[0090] Example 1 This embodiment provides a functional patterned electrode sheet, which is a positive electrode sheet, and its cross-sectional view is shown below. Figure 1As shown, it specifically includes a current collector 1 and an active layer 2 disposed on both sides of the current collector 1; the active layer 2 includes the active material NCM811, and the thickness of the active layer 2 on one side is 120μm; The active layer 2 has a patterned surface on the side away from the current collector 1; the patterned surface is composed of a plurality of periodically alternating grooves 3 and protrusions 4; the grooves 3 and protrusions 4 are all straight strips; and the depth of the grooves 3 ( Figure 1 The H in the figure is 25 μm, which is equal to 20.3% of the thickness of the active layer 2; the width of the groove 3 ( Figure 1 The width of W is 200 μm; the width of protrusion 4 is 400 μm, that is, the period is 600 μm; like Figure 1 As shown, an interface stabilizing functional layer 5 is provided on the bottom and sidewall surfaces of the groove 3, while the top surface of the protrusion 4 and the non-patterned surface (collectively referred to as the flat surface) of the active layer 2 are not provided with the interface stabilizing functional layer 5. The interface stabilizing functional layer 5 is composed of an oligomeric copolymer with a mass ratio of 80% and a first binder PVDF with a mass ratio of 20%. The raw materials forming the oligomeric copolymer include monomers and crosslinking agents, both of which have polymerizable unsaturated bonds. The monomer is VEC, and the crosslinking agent is polyethylene glycol diacrylate, so that the oligomeric copolymer contains ethylene carbonate structural units (i.e., the ethylene carbonate structure in VEC). The molecular weight of the oligomeric copolymer is 1500 Da. The thickness of the interface stabilizing functional layer 5 is 2.5 μm, which is equal to 10% of the depth of the groove 3. And it is calculated that the mass of the interface functional layer accounts for 0.08% of the mass of the active layer 2.

[0091] The method for preparing the functional patterned electrode includes: S1. Prepare the electrode sheet and perform patterning treatment: Coat the active layer 2 slurry on the surface of the current collector 1, dry it, roll it, and then use an embossing roller to emboss the surface of the rolled active layer 2 to form grooves 3 and protrusions 4, thus obtaining a patterned electrode sheet; calculate the total volume of the grooves 3 and the mass of the active layer 2 according to the pattern design (calculated based on the active layer thickness, areal density and electrode sheet area). S2. Preparation of oligomeric copolymers and formulation of functional layer solutions: The monomer, crosslinking agent, initiator AIBN (1.1% of the monomer mass), chain transfer agent DDT (3% of the monomer mass) and solvent dimethyl carbonate are mixed and polymerized at 65°C. The molecular weight is controlled by the chain transfer agent. After precipitation and purification, the product is dried to obtain the oligomeric copolymer. The dried oligomeric copolymer, the first binder, and the solvent DMC were mixed to obtain a functional layer solution with a mass percentage concentration of 2.2% of the oligomeric copolymer. S3. Spraying and negative pressure suction treatment: The patterned side of the patterned electrode obtained in step S2 is set towards the atomizing nozzle 6, and the other side is set towards the negative pressure suction nozzle 7. Each groove 3 corresponds to a negative pressure suction nozzle 7. The negative pressure suction nozzles 7 are all connected to the vacuum pump 8, and negative pressure suction can be performed through the vacuum pump 8. The distance between the negative pressure suction nozzle 7 and the electrode surface is 0.022mm. The functional layer solution is sprayed as atomized droplets through the atomizing nozzle 6 to coat the patterned surface. Simultaneously, air is drawn in through the negative pressure nozzle 7 to create a directional airflow at a negative pressure of -0.05 MPa, controlling the amount of functional layer solution used to be 1.4 times the total volume of the groove 3. Figure 2 As shown, the atomizing nozzle 6 sprays the functional layer solution onto the electrode surface, while a negative pressure is applied to the negative pressure suction nozzle 7 on the back of the electrode. The dashed lines in the figure clearly indicate the airflow path: the main airflow enters from above the groove 3, penetrates downwards through the residual thickness of the active material layer and the submicron-level defects of the current collector 1, and flows into the negative pressure suction nozzle 7; the lateral airflow enters from the edge of the electrode and the lateral micropores of the active material layer to supplement it. This composite airflow carries away the excess solution on the outer flat surface of the groove 3, allowing the functional layer solution to be selectively retained on the inner surface of the groove 3 under the combined action of capillary effect and directional airflow, and no functional layer solution remains on the flat surface and the top surface of the protrusion 4; the amount of functional layer solution used is recorded to calculate the quality of the interfacial functional layer. S4. The patterned electrode obtained in step S3 is dried at 65°C for 16 minutes to allow the solvent to evaporate, forming an interface stabilizing functional layer 5 covering the bottom and sidewalls inside the groove 3; after slitting, a functional patterned electrode is obtained.

[0092] Example 2 The difference from Example 1 is that the monomer is replaced with acrylate monomer and the crosslinking agent is replaced with polyvinyl carbonate oligomer, so that the oligomer contains ethylene carbonate structural units (i.e., ethylene carbonate structure in VC); at the same time, the ratio of oligomer to binder is adjusted so that the interface stabilizing functional layer 5 contains 85% oligomer and 15% first binder. Apart from the above, the other conditions are exactly the same as in Example 1.

[0093] Example 3 The difference from Example 1 is that the mass percentage concentration of the oligomeric copolymer in the functional layer solution is adjusted from 2.2% to 4%, so that the thickness of the interface-stabilized functional layer 5 formed in the groove 3 is adjusted from 2.5 μm to 3.75 μm, which is equal to 15% of the depth of the groove 3. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0094] Example 4 The difference from Example 1 is that the mass percentage concentration of the oligomeric copolymer in the functional layer solution is adjusted from 2.2% to 1%, so that the thickness of the interface-stabilized functional layer 5 formed in the groove 3 is adjusted from 2.5 μm to 1.25 μm, which is equal to 5% of the depth of the groove 3. Apart from the above, the other conditions are exactly the same as in Example 1.

[0095] Example 5 The difference from Example 1 is that in step S3, the distance between the negative pressure suction nozzle 7 and the electrode surface is adjusted from 0.022mm to 0.01mm. Apart from the above, the other conditions are exactly the same as in Example 1.

[0096] Example 6 The difference from Example 1 is that in step S3, the distance between the negative pressure suction nozzle 7 and the electrode surface is adjusted from 0.022mm to 0.05mm. Apart from the above, the other conditions are exactly the same as in Example 1.

[0097] Example 7 The difference from Example 1 is that in step S3, the negative pressure is adjusted from -0.05MPa to -0.01MPa. Apart from the above, the other conditions are exactly the same as in Example 1.

[0098] Example 8 The difference from Example 1 is that in step S3, the negative pressure is adjusted from -0.05MPa to -0.1MPa. Apart from the above, the other conditions are exactly the same as in Example 1.

[0099] Example 9 The difference from Example 1 is that in step S3, the amount of functional layer solution is adjusted from 1.4 times the total volume of the groove 3 to 1 time, while other conditions are exactly the same as in Example 1.

[0100] Example 10 The difference from Example 1 is that in step S3, the amount of functional layer solution is adjusted from 1.4 times the total volume of the groove 3 to 1.2 times, while other conditions are exactly the same as in Example 1.

[0101] Example 11 The difference from Example 1 is that in step S3, the amount of functional layer solution is adjusted from 1.4 times to 1.5 times the total volume of the groove 3, while other conditions are exactly the same as in Example 1.

[0102] Comparative Example 1 The difference from Example 1 is that only patterned electrode sheets are used for subsequent testing, and the interface stabilization functional layer 5 is not set in the groove 3. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0103] Comparative Example 2 The difference from Example 1 is that in step S3, only a single full-surface spraying is performed without negative pressure suction treatment, so that the functional layer solution and the formed interface-stabilized functional layer 5 cover the entire surface of the active layer 2. Apart from the above, the other conditions are exactly the same as in Example 1.

[0104] Comparative Example 3 The difference from Example 1 is that the size of the negative pressure suction nozzle 7 is adjusted to be smaller than the width of the groove 3 and the amount of functional layer solution is adjusted to 0.5 times the total volume of the groove 3, so that the interface stabilizing functional layer 5 is formed only at the bottom of the groove 3. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0105] Comparative Example 4 The difference from Example 1 is that in step S3, the distance between the negative pressure suction nozzle 7 and the electrode surface is adjusted from 0.022mm to 0.1mm. Apart from the above, the other conditions are exactly the same as in Example 1.

[0106] Comparative Example 5 The difference from Example 1 is that in step S3, the negative pressure is adjusted from -0.05MPa to -0.2MPa. Apart from the above, the other conditions are exactly the same as in Example 1.

[0107] Comparative Example 6 The difference from Example 1 is that in step S3, the amount of functional layer solution is adjusted from 1.4 times the total volume of the groove 3 to 2 times, while other conditions are exactly the same as in Example 1.

[0108] Characterization and Testing The functional patterned electrode (positive electrode) obtained from the above embodiments and comparative examples was assembled with a lithium metal counter electrode to form a CR2032 coin cell. The specific assembly method was as follows: In a glove box filled with argon (water and oxygen content both <0.1ppm), the functional patterned electrode was used as the positive electrode, the lithium metal sheet was used as the negative electrode, and a Celgard 2325 type (PP / PE / PP) three-layer composite polyolefin membrane was used as the separator. An electrolyte (lithium salt is 1M LiPF6, solvent is a mixed solvent of ethylene carbonate EC, ethyl methyl carbonate EMC and diethyl carbonate DEC in a volume ratio of 1:1:1, with 10wt% fluoroethylene carbonate FEC and 1wt% lithium difluorooxalate borate LiDFOB as additives) was added. After encapsulation, it was left to stand for 12 hours before testing.

[0109] All electrochemical tests were conducted at a constant temperature of 25°C using LAND or Arbin battery testing systems. Specific testing conditions are as follows: (1) Initial charge and discharge efficiency test: The first constant current charge and discharge was performed at a current density of 0.05C (1C=500mA / g, calculated based on the mass of the positive electrode active material). The charging cutoff voltage was 4.3V and the discharging cutoff voltage was 2.8V. The initial coulombic efficiency (%) = initial discharge capacity / initial charge capacity × 100%.

[0110] (2) Cyclic stability test: The battery was activated by cycling at 0.1C rate for 3 weeks, and then subjected to long-term cycle test at 0.5C rate for 2000 cycles, and the discharge capacity was recorded each week. 2000-cycle capacity retention rate (%) = discharge capacity in week 2000 / discharge capacity in week 4 × 100%.

[0111] (3) Test of the shedding rate at the root of the groove: After the battery has been cycled for 2000 cycles, the functional patterned electrode is removed, and the residual electrolyte is removed by cleaning with DMC solvent. After drying, the cross section of the electrode is observed by SEM (scanning electron microscope). 20 groove root areas are randomly selected, and the number of grooves in which the active layer has detached is counted by image analysis software. The shedding rate (%) = number of grooves in which shedding occurred / total number of grooves observed × 100%.

[0112] (4) Test of electrolyte retention rate in grooves: The weighing method is used. The electrode to be tested is immersed in the electrolyte and fully wetted. After taking it out, the excess liquid droplets on the surface are gently absorbed with lint-free paper, and the mass m1 after immersion is weighed. Then, the same method is used to treat the flat electrode of the same size but without grooves, and the mass is weighed as m0. The electrolyte retention rate (%) = (m1-m0) / (theoretical total volume of grooves of the same size × electrolyte density) × 100%.

[0113] (5) The ratio of the interface-stabilized functional layer to the active layer: The total mass of the functional layer is estimated based on the concentration of the functional layer solution, the total amount of solution used, and the ratio of oligomeric copolymer to PVDF in the functional layer. Then, the total mass of the active layer is calculated based on the thickness of the active layer, the areal density, and the area of ​​the electrode. The ratio of the two is the percentage.

[0114] The test results are shown in Table 1 below.

[0115] Table 1 As can be seen from Table 1: In Example 1, with an extremely low amount of functional layer solution, the formed interface-stabilized functional layer accounted for 0.08% of the active layer mass. Compared to Comparative Example 1, the formation of the interface-stabilized functional layer significantly reduced the root shedding rate of the groove from 8.5% to 2.1% (a reduction of 75.3%), while maintaining the groove's reservoir function (98% retention rate). The initial coulombic efficiency of Example 1 (89.5%) was slightly lower than that of Comparative Example 1 (89.8%). This is because the functional layer underwent electrochemical decomposition during initial formation to form a LiF-rich interface film, consuming a small amount of active lithium. However, this interface film effectively suppressed side reactions in subsequent cycles, thereby significantly improving the long-term cycling capacity retention rate (94.8% vs 89.2%). Example 2 shows that utilizing the characteristic groups in VC to retain it in the oligomeric copolymer is also effective. Examples 3 and 4 show that appropriately increasing the thickness can further reduce the shedding rate, but the reservoir retention rate decreases slightly; when the thickness is too thin, the film-forming effect weakens, and the shedding rate increases. Examples 5 and 6 demonstrate that effective selective coating can be achieved when the distance between the negative pressure nozzles is ≤0.05mm. Examples 7 and 8 demonstrate that selective coating can be effectively implemented when the negative pressure is within the range of -0.01 to -0.1MPa. Examples 9 and 11 demonstrate that the effect is better when the amount of functional layer solution is within the range of 1 to 1.5 times the total volume of the groove. Although Comparative Example 2 (full-surface coating) reduced the peeling rate to some extent, the groove's liquid storage function was severely lost (62%), and the large amount of functional material used (2.5%) led to a significant decrease in the initial coulombic efficiency (87.2%). Comparative Example 3 only covered the bottom, leaving the root of the sidewalls exposed to the electrolyte. Microcracks initiated from the root of the sidewalls, resulting in limited improvement in the peeling rate (5.2%). This indicates that full coverage of both the bottom and sidewalls of the groove is necessary to effectively suppress the propagation of microcracks in the stress concentration zone at the root of the groove. Comparative Examples 4 to 6 show that when the process parameters exceed the preferred range of the present invention, the coating effect deteriorates significantly, the groove liquid storage function is damaged, or the peeling rate is not significantly improved.

[0116] In summary, the functional patterned electrode provided by this invention features an interface stabilizing layer on the bottom and sidewalls of the grooves on the patterned surface. This interface stabilizing layer comprises an oligomeric copolymer containing electrochemically active ethylene carbonate structural units. This oligomeric copolymer functions as a film-forming additive, preferentially reacting with the electrolyte during the first charge (formation) of the battery. This forms a stable LiF-rich interface film on the inner surface of the groove, effectively suppressing side reactions and microcrack propagation in the high-stress region at the groove root. This significantly improves the electrode's cycle performance and long-term stability, reducing the active layer shedding rate in the groove root region by over 75% after 2000 cycles. Since the interface stabilizing layer is located on the inner surface of the groove, it does not affect the electrolyte conduction / storage function and helps maintain the overall energy density of the electrode.

[0117] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0118] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0119] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A functional patterned electrode sheet, characterized in that, The device includes a current collector and an active layer disposed on at least one side of the current collector; the active layer has a patterned surface on the side away from the current collector; the patterned surface includes grooves and protrusions; an interface stabilizing functional layer is disposed on the bottom and sidewall surfaces of the grooves; the interface stabilizing functional layer is composed of an oligomeric copolymer containing ethylene carbonate structural units.

2. The functional patterned electrode sheet according to claim 1, characterized in that, The interface stabilization layer is not provided on the top surface of the protrusion and / or on the non-patterned surfaces of the active layer other than the patterned surface.

3. The functional patterned electrode sheet according to claim 1, characterized in that, The functional patterned electrode sheet satisfies at least one of the following conditions: (A1) The depth of the groove is 5% to 40% of the thickness of the active layer; (A2) The depth of the groove is 1μm~50μm; (A3) The width of the groove is 50μm~500μm; (A4) The thickness of the interface stabilizing functional layer is 5% to 15% of the depth of the groove; (A5) The mass of the interface stabilizing functional layer accounts for 0.01% to 0.5% of the mass of the active layer.

4. The functional patterned electrode sheet according to claim 1, characterized in that, The raw materials forming the oligomeric copolymer include monomers and crosslinking agents, both having polymerizable unsaturated bonds; and satisfy at least one of the following conditions: (B1) The monomer comprises a cyclic carbonate corresponding to the ethylene carbonate structural unit, and / or the crosslinking agent contains the ethylene carbonate structural unit; (B2) When the monomer includes the cyclic carbonate, the cyclic carbonate is a film-forming additive, and the film-forming additive includes VC and / or VEC; (B3) When the monomer is not the cyclic carbonate, the monomer includes acrylate; (B4) When the crosslinking agent contains the ethylene carbonate structural unit, the crosslinking agent includes polyvinyl carbonate oligomers; (B5) When the crosslinking agent does not contain the ethylene carbonate structural unit, the crosslinking agent includes polyethylene glycol diacrylate.

5. The functional patterned electrode sheet according to claim 1, characterized in that, The molecular weight of the oligomeric copolymer is 200 Da to 6000 Da.

6. The functional patterned electrode sheet according to claim 1, characterized in that, The interface stabilization functional layer also includes a first adhesive; The first adhesive comprises PVDF; and / or, based on the mass of the interface stabilizing functional layer as 100%, the proportion of the first adhesive is 5% to 30%.

7. A method for preparing a functional patterned electrode sheet, characterized in that, Includes the following steps: A patterned electrode is provided, the patterned electrode comprising a current collector and an active layer disposed on at least one side of the current collector; the active layer having a patterned surface on the side away from the current collector; the patterned surface comprising grooves and protrusions; An oligomeric copolymer is provided, the oligomeric copolymer containing ethylene carbonate structural units; the oligomeric copolymer is prepared with a first solvent to form a functional layer solution; The functional layer solution is coated on one side of the patterned electrode with the patterned surface, while a negative pressure suction process is performed on the other side of the patterned electrode to allow the functional layer solution to enter and remain in the groove. The first solvent is removed by drying, and an interface-stabilizing functional layer is formed on the bottom and sidewall surfaces of the groove to obtain a functional patterned electrode.

8. The method for preparing a functional patterned electrode sheet according to claim 7, characterized in that, The preparation method satisfies at least one of the following conditions: (C1) The first solvent includes dimethyl carbonate; (C2) The mass percentage concentration of the oligomeric copolymer in the functional layer solution is 0.5%~5%; (C3) The coating method includes spraying; (C4) The amount of the functional layer solution used is 1 to 2 times the total volume of the groove; (C5) The negative pressure of the negative pressure suction treatment is -0.01MPa to -0.1MPa; (C6) The negative pressure suction process is carried out through a negative pressure suction nozzle, and the distance between the negative pressure suction nozzle and the surface of the patterned electrode is ≤0.05mm; (C7) In the negative pressure suction process, each of the grooves corresponds to at least one negative pressure nozzle, or each negative pressure nozzle corresponds to at least one of the grooves; (C8) The drying temperature is 40℃~80℃ and the time is 5min~20min.

9. The method for preparing a functional patterned electrode sheet according to claim 7, characterized in that, The method for preparing the oligomeric copolymer includes: The invention provides monomers and crosslinking agents, both having polymerizable unsaturated bonds; wherein the monomers include cyclic carbonates corresponding to the ethylene carbonate structural units, and / or the crosslinking agents contain the ethylene carbonate structural units; The monomer, crosslinking agent, initiator, chain transfer agent and second solvent are mixed and polymerized to obtain an oligomeric copolymer; The polymerization reaction satisfies at least one of the following conditions: (D1) The polymerization reaction temperature is 50℃~80℃; (D2) The initiator includes azobisisobutyronitrile; (D3) The amount of the initiator is 0.5% to 2% of the mass of the monomer; (D4) The chain transfer agent includes dodecyl mercaptan; (D5) The amount of the chain transfer agent is 1% to 5% of the mass of the monomer; (D6) The second solvent includes dimethyl carbonate.

10. A battery, characterized in that, The electrode comprises the functional patterned electrode according to any one of claims 1-6, or the functional patterned electrode obtained by the preparation method according to any one of claims 7-9.

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