Lithium composite and method for producing the same

Abstract

The present invention provides a lithium composite and a method for producing the same, which is tape-shaped and includes a structural layer, a stress-balancing layer located on at least one surface of the structural layer and having a patterned metallic lithium and / or lithium alloy and a thickness of 0.1 to 1 μm, and a lithium membrane having a width of 185 to 1500 mm, a uniform thickness of 0.5 to 30 μm, and a thickness tolerance of 20% or less, the lithium membrane being combined with the structural layer via the stress-balancing layer to form the lithium composite.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and particularly to an ultra-thin and ultra-wide lithium composite that can be used in secondary batteries and a method for manufacturing the same.

Background Art

[0002] Lithium batteries are widely applied in fields such as aviation and space, computers, mobile communication devices, robots, and electric vehicles due to their advantages of high energy density, long cycle life, and wide applicable temperature range. With the development of society and the progress of science and technology, the requirements for the energy density and cycle life of lithium batteries are becoming increasingly high. Conventionally, lithium-ion batteries with only graphite as the negative electrode cannot meet the expectations of society, so the development of new positive and negative electrode materials with higher specific capacity is required. Regarding the negative electrode material, it is ideal to use metallic lithium as the negative electrode. Metallic lithium has a high specific capacity (3860 mAh / g, which is 10 times that of the graphite negative electrode) and the lowest redox potential (-3.04 V vs. standard hydrogen potential). By adopting metallic lithium as the negative electrode, the specific energy of the battery can be significantly improved, and lithium-ion batteries will be applied in a wider range of fields.

[0003] Currently, commercially available lithium-ion batteries employ lithium-containing materials as positive electrode materials (e.g., lithium cobalt oxide, lithium iron phosphate, ternary materials, etc.). The lithium contained in the positive electrode already satisfies the charge and discharge requirements of lithium-ion batteries. The negative electrode only needs to provide a small amount of lithium to compensate for lithium loss during the cycle process and to guide the deposition of lithium ions in the positive electrode, thereby significantly improving the energy density of the battery. The amount of lithium required for the negative electrode is very small; typically, for lithium films used in batteries, a thickness of 0.5 to 30 microns is sufficient. Furthermore, in order to be compatible with conventional lithium-ion batteries, there are high requirements for the width of the metallic lithium negative electrode. In particular, current blade batteries require extremely high widths for the negative electrode, and conventional metallic lithium negative electrodes cannot achieve both ultra-thinness and ultra-wideness. In light of this, there is a need for technology to realize ultra-thin and ultra-wide metallic lithium. [Overview of the project]

[0004] The inventors unexpectedly discovered that, when the stress between the ultrathin lithium film and the structural layer is well balanced in a lithium composite containing an extremely thin (thickness of 30 microns or less) metallic lithium film and a structural layer, it is possible to manufacture an ultrathin, ultrawide metallic lithium composite (in which case the lithium film thickness is 30 microns or less and the width is 150 mm or more, for example, 185 mm or more). By constructing a stress-equalization layer of patterned metallic lithium and / or lithium alloy on the structural layer, the accumulation of stress inside the lithium film during the rolling process is alleviated to some extent, making the lithium film less prone to deformation during the composite process, and enabling the manufacture of a lithium composite having a wider, thinner, and more uniform lithium film (for example, 1-5 microns). Based on these findings, the present invention was arrived at.

[0005] Accordingly, one aspect of the present invention provides a lithium composite, which is in the form of a tape, comprising a structural layer and a stress equilibrium layer located on at least one surface of the structural layer, having a patterned metallic lithium and / or lithium alloy, and having a thickness of 0.1 to 1 μm. A lithium film having a width of 185 to 1500 mm, a uniform thickness of 0.5 to 30 microns, and a thickness tolerance of within 20% of the thickness, Equipped with, The lithium film is composited with the structural layer via the stress equilibrium layer to form the lithium composite.

[0006] The lithium composite of the present invention is a composite strip containing an ultrathin and ultrabroad lithium film, the ultrathin and ultrabroad lithium film being continuous or intermittent, having or not having through holes, supported by a structural layer (copper foil substrate), and having adjustable width and thickness (controlling stress equilibrium layer and pressure).

[0007] In the present invention, the lithium film is a uniform film, that is, the lithium film has a perfect film shape (without obvious wrinkles or deformation and with clean boundaries) and a uniform thickness.

[0008] In the present invention, the lithium film may be continuous or discontinuous in the longitudinal or widthwise direction.

[0009] Optionally, the intermittent lithium film in the longitudinal direction has a metallic lithium layer area length range of 1 to 2000 mm and a blank area length range of 1 to 200 mm.

[0010] As an optional choice, the lithium film, which is intermittent in the width direction, has a metallic lithium layer area width of 1 to 200 mm and a spacing between metallic lithium layers of 0.5 to 10 mm.

[0011] Optionally, the lithium film surface of the lithium composite may be glossy, metallic silver-white in color, have a lithium content of 99.90-99.95%, and the lithium element content of the lithium film body (inside) may be 99.95-99.99%. The thickness range of the lithium film is 0.5-30 microns, preferably 1-20 microns, more preferably 10 microns or less, most preferably 1-5 microns, and the thickness tolerance is within 20% of the thickness, preferably within 15%.

[0012] Optionally, the lithium film is lithium and / or various lithium alloys, including an alloy of lithium with one or more of the following: silicon, magnesium, aluminum, indium, boron, tin, gallium, yttrium, silver, copper, lead, bismuth, sodium, carbon, germanium, titanium, chromium, cobalt, tungsten, iron, niobium, nickel, gold, barium, cadmium, cesium, calcium, manganese, nitrogen, platinum, sulfur, thallium, strontium, tellurium, zinc, antimony, and zirconium, and the lithium content in the lithium alloy may be 70% or more, and even 90% or more.

[0013] Optionally, the stress equilibrium layer comprises patterned metallic lithium and / or lithium alloys, the patterned metallic lithium and / or lithium alloys being in the form of stripe-like patterns or arrays formed of elongated or linear metallic lithium and / or lithium alloys, the width of the elongated or linear metallic lithium and / or lithium alloys being 0.5 to 5 mm, the spacing distance of the stripe-like patterns being 1 to 3 mm, and the arrays including equilateral polygonal arrays, with sides ≥ 3 and side lengths being 2 to 15 mm.

[0014] Optionally, the ratio of the area of ​​equilateral polygonal metallic lithium and / or lithium alloy in the stress equilibrium layer to the area of ​​the gaps is 1.2 to 20, preferably 2 to 6, and optionally, stripe-shaped metal The ratio of the width to the spacing distance of lithium and / or lithium alloy is 1 / 4 to 3, preferably 1 / 3 to 1.5.

[0015] Optionally, the structural layer material is either a metallic copper material or a single-layer or multi-layer copper-organic material composite, where the organic material is at least one of polyethylene terephthalate, polypropylene, polyvinyl chloride, and polyimide.

[0016] Optionally, the thickness of the structural layer is 3.5 to 20 microns, preferably 3.5 to 10 microns, and more preferably 3.5 to 6 microns.

[0017] Optionally, the contact surface between the structural layer and the metallic lithium is subjected to stress balancing treatment, and preferably, metallic lithium is deposited on the contact surface between the structural layer and the metallic lithium.

[0018] Another aspect of the present invention provides a method for producing the lithium composite described above, the method comprising the steps of: forming patterned metallic lithium and / or lithium alloy on a structural layer by pressure compounding, spraying, dip transfer coating, extrusion coating, scraper coating, curtain coating, screen printing, vapor deposition or vapor phase growth to obtain a stress equilibrium layer; and using metallic lithium strips with a thickness of 5 to 2000 μm as raw materials, rolling the metallic lithium strips by rolling to compound them on the stress equilibrium layer to obtain the lithium composite.

[0019] As an optional choice, a roll-to-roll continuous manufacturing method may be employed in the above lithium composite manufacturing method.

[0020] Optionally, the thickness of the lithium metal strip is 10 to 100 μm, preferably 10 to 50 μm.

[0021] Optionally, the rolling process includes cold rolling, hot rolling, or combined rolling, with the temperature range for hot rolling controlled to 60-120°C, and in combined rolling, preferably hot rolling followed by cold rolling.

[0022] Optionally, the rolling pressure range is 0.1 to 150 MPa, preferably 80 to 120 MPa.

[0023] As an optional measure, the contact stress between the ultrathin / ultrawide lithium film and the structural layer can be controlled by controlling the stress equilibrium layer.

[0024] Optionally, the surface of the rolling roller has an anti-adhesion material, which includes polyethylene, polyformaldehyde, silicone polymer, or ceramics.

[0025] Optionally, a roller with a maximum tension range of 0.1 - 10 N is adopted for winding, and the support roller itself has power.

[0026] By controlling the rolling process, the present invention can obtain a complex of ultra-thin and ultra-wide lithium films with a simple process. The complex has a high specific energy, and when applied to the negative electrode of a lithium battery, it has the effect of improving the energy density and can achieve a high energy density of the battery. Since the metallic lithium negative electrode has a high gram specific capacity, it is applicable to high-energy batteries, and the energy density of the battery can exceed 450 wh / kg.

[0027] Commercially available battery sizes are increasing, and the required width of the metallic lithium negative electrode is also becoming wider. The ultra-wide and ultra-thin lithium film conforms to the development trend of currently commercially available batteries. The present invention can easily and mass-produce an ultra-wide and ultra-thin metallic lithium composite. The ultra-thin metallic lithium negative electrode is suitable for current high-gram-capacity positive electrodes and does not cause problems of lithium excess and dendrites.

[0028] The bonding of metallic lithium and the current collector is a difficult problem in the industry. Since complete bonding is very difficult, the current collection effect is poor, and the battery rate performance is poor. The ultra-thin and ultra-wide metallic lithium composite of the present invention can well solve the above problems. By introducing a patterned stress balance layer, metallic lithium and the structural layer can be closely bonded. Also, when the patterned layer is made of metallic lithium, no other impurity elements are introduced into the final product.

Brief Description of the Drawings

[0029] [Figure 1] Figure 1 is a schematic process diagram for manufacturing a continuous ultra-thin and ultra-wide lithium composite by pressure compounding of the present invention. [Figure 2]Figure 2 is a schematic diagram of an ultrathin, ultrabroad lithium composite that is discontinuous in the width direction. [Figure 3] Figure 3 is a schematic diagram of a discontinuous ultrathin and ultrabroad lithium composite in the longitudinal direction. [Figure 4] Figure 4 is a schematic diagram of a manufacturing apparatus for intermittent ultrathin and ultrabroad lithium composites. [Figure 5] Figure 5 shows a schematic diagram of the patterning (stripe-like) in the stress equilibrium layer of the present invention. [Figure 6] Figure 6 shows a schematic diagram of the patterning (triangle) in another stress equilibrium layer of the present invention. [Figure 7] Figure 7 shows a schematic diagram of another stress equilibrium layer in the present invention, with a patterned (square, grid) design. [Figure 8] Figure 8 shows a diagram of an ultra-thin, ultra-wide lithium composite product with a thickness of 5 microns manufactured in Example 1 of the present application. [Figure 9] Figure 9 shows a diagram of a 5-micron thick, intermittent, ultra-thin, ultra-wide lithium composite product manufactured in Example 2 of the present application. [Figure 10] Figure 10 shows a diagram of an ultra-thin, ultra-wide lithium composite product with a thickness of 5 microns manufactured in Comparative Example 2 of the present application. [Figure 11] Figure 11 shows the electrochemical performance diagram of an ultrathin, ultrabroad lithium composite product with a thickness of 5 microns manufactured in Example 1 of the present application. [Explanation of symbols]

[0030] P structure layer L Metallic Lithium Layer PL (Continuous) Lithium Foil PNL Intermittent Lithium Foil H Lithium layer or alloyed layer [Modes for carrying out the invention]

[0031] To make the object, technical solution, and advantages of the present invention clearer and more evident, the present invention will be described in more detail below with reference to the drawings and examples. The specific examples described herein should be understood to be for interpretation purposes only and not to limit the present invention. The technical features of the embodiments of the present invention described below may be combined with each other, insofar as they do not conflict with each other.

[0032] Figure 1 shows a schematic diagram of the process for manufacturing a continuous ultrathin, ultrawide lithium composite by the pressure composite of the present invention. As shown in Figure 1, a metallic lithium strip and a structural layer strip (pre-patterned) having a stress balance layer are used as raw materials, and the strips are unwound by an unwinding device, which includes at least a metallic lithium strip unwinding roller 11 and two unwinding support rollers 12 for supporting the metallic lithium strip and structural layer strip being unwound, respectively. The lithium strip and structural layer strip, which are the raw materials, enter a rolling mill 20 after passing through the unwinding support rollers 12, which includes at least one pair of rolling rollers 21 and an anti-adhesion coating layer 22 on the rolling rollers 21, and the rolling pressure of the rolling mill 20 and the roller gap between the rolling rollers 21 are finely adjustable. The material of the anti-adhesion coating layer 22 on the rolling rollers 21 may be one or more selected materials such as polyethylene, polyformaldehyde, silicone polymer, and ceramics. By pressurized compounding, a structural layer strip and a lithium strip are combined to form an ultra-thin, ultra-wide lithium composite product. A winding device is provided on the outlet side of the rolling mill 20, and the winding device includes at least a support roller 31, a tension control roller 32, and a winding roller 33. In particular, the support roller 31 is powered and can pull the ultra-thin, ultra-wide lithium composite forward with a small traction force, and the tension control roller 32 can move up and down or swing, and can not only control the tension of the preform but also control the winding speed of the winding roller 33 according to the height or swing angle of the tension control roller 32.

[0033] Figure 2 is a schematic diagram of a discontinuous lithium film in the width direction. Figure 3 is a schematic diagram of a discontinuous lithium film in the longitudinal direction.

[0034] Figure 4 shows a manufacturing apparatus for producing intermittent lithium films, which includes an unwinding device 100, a scraping device 200, and a winding device 300, and further includes a control device (not shown) for controlling the winding speed and the operating time interval of the scraping device. In particular, the unwinding device 100 includes an unwinding shaft 101, a magnetic powder brake 102, an unwinding support roller 104, an unwinding deviation correction detection sensor 105, and an unwinding deviation correction device 103, and the scraping device 200 includes a scraper 201, a scraper drive device 202, a scraper pad 203, and support rollers (204, 205). The winding device 300 includes a winding shaft 301, a winding motor 302, a winding deviation correction device 303, a winding support roller 304, and a winding deviation correction detection sensor 305. A length measuring sensor 401 may also be provided.

[0035] The unwinding shaft 101 on the unwinding device 100 is used to unwind the lithium foil PL, and a magnetic powder brake 102 connected to the unwinding shaft 101 can control the magnitude of the unwinding tension. The unwinding support roller 104 guides the lithium foil PL into the scraping device 200 at a constant inclination angle and supports it so that the unwinding deviation correction detection sensor 105 can accurately detect deviations in the lithium foil PL. The support rollers 204 / 205 on the scraping device 200 each ensure that the inclination angle of the strip advancing through the device remains constant and unaffected by other process stages. The scraper pad 203 supports the lithium foil PL and keeps it flat. The scraper drive unit 202 drives the scraper 201 to move rapidly in the vertical direction. The winding device 300 includes a winding shaft 301 and a winding motor 302. The winding shaft 301 is used for intermittent winding of lithium foil PNL, and the winding shaft 301 is driven by a winding motor 302.

[0036] The specific method and process flow are as follows: A battery-grade lithium foil PL with a base material support is attached and fixed to the unwinding shaft 101. The lithium foil PL is sequentially passed through the unwinding support roller 104, the unwinding deviation correction detection sensor 105, the support rollers 204 and 205 of the scraping device, the winding deviation correction detection sensor 305, and the winding support roller 304, and then wound and fixed onto the winding shaft 301. The device is started, the winding motor 302 on the winding device 300 is activated, the winding shaft 301 is rotated, and the lithium foil PL is wound from the unwinding device 100 side through the scraping device 200. During the winding process, the scraper 201 is intermittently moved up and down by controlling the scraper drive unit 202 in the scraping device 200, thereby scraping off a portion of the metallic lithium layer on the lithium foil PL, forming an intermittent lithium foil PNL, and an intermittent lithium film in the width direction is manufactured by controlling the width and number of scrapers.

[0037] Figure 5 shows a schematic diagram of the striped patterned stress equilibrium layer of the present invention. Figure 6 shows a schematic diagram of the triangular patterned stress equilibrium layer of the present invention. Figure 7 shows a schematic diagram of the square patterned stress equilibrium layer (grid pattern) of the present invention. [Examples]

[0038] The present invention will be described more specifically below with reference to examples using the above-described process apparatus. The structural parameters of the various products, the various reactants, and the process conditions used in the following examples are all typical examples. However, as a result of verification by the inventors through a large number of tests, other different structural parameters, other types of reactants, and other process conditions listed above are also applicable and can achieve the technical effects claimed by the present invention.

[0039] Example 1: A metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 185 mm, and a copper foil with a thickness of 8 microns (a stripe-shaped metallic lithium layer (thickness 0.4 μm) was deposited on the surface of the copper foil as a stress-equalization layer, with a lithium width (specifically, 3 mm) and spacing ratio of 1.5) were used. Using an unwinding and winding device, the material was cold-rolled under a controlled pressure of 80 MPa to obtain an ultra-thin, ultra-wide lithium composite product with a metallic lithium thickness of 5 microns (thickness tolerance of ±0.5 microns). Figure 8 shows the ultra-thin, ultra-wide lithium composite product. As can be seen from Figure 8, the ultra-thin, ultra-wide lithium film has a perfect film shape.

[0040] Example 2 A metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 185 mm, and a copper foil with a thickness of 8 microns (a metallic lithium-magnesium alloy in a square grid pattern is deposited on the surface of the copper foil as a stress equilibrium layer (thickness 0.1 μm), and lithium of width but 0.5mm and Using a method that involves a side length of 3 mm and an area ratio controlled to 2.25, and employing an unwinding, winding, and scraping device, a discontinuous ultra-thin, ultra-wide lithium composite product in the longitudinal direction with a lithium layer thickness of 5 microns (thickness tolerance of ±0.5 microns) was obtained by hot rolling at a temperature of 80°C and a pressure controlled to 100 MPa (for example, Figure 9).

[0041] Example 3 A metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 800 mm, and a copper foil with a thickness of 8 microns (a triangular metallic lithium layer is deposited on the surface of the copper foil as a stress balance layer (thickness of 0.2 microns), and lithium The width 1mm and Using a triangular body with a side length of 3 mm and a ratio of 2 between the area of ​​the triangular body and the area of ​​the gap within the triangle, an ultra-thin, ultra-wide lithium composite product was obtained by cold rolling using an unwinding and winding device, with the pressure controlled to 120 MPa, and the metallic lithium thickness being 1 micron (with a thickness tolerance of ±0.5 microns).

[0042] Comparative Example 1 Using a metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 185 mm, and a copper foil with a thickness of 8 microns (the surface of the copper foil was not treated), and employing an unwinding and winding device, cold rolling was performed with a controlled pressure of 100 MPa. However, an ultra-thin, ultra-wide lithium composite product with a metallic lithium thickness of 5 microns (thickness tolerance of ±0.5 microns) could not be obtained (lithium and copper cannot be composited).

[0043] Comparative Example 2 Using a metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 185 mm, and a copper foil with a thickness of 8 microns (a stripe-shaped metallic lithium layer (0.5 microns thick) was deposited on the surface of the copper foil as a stress-equalization layer, with a lithium width of 0.5 mm, a spacing distance of 2.5 mm, and a ratio of the two controlled to 0.2), and using an unwinding and winding device, cold rolling was performed with a pressure controlled to 100 MPa, but an ultra-thin, ultra-wide lithium composite product with uniformity, continuity, and a metallic lithium thickness of 5 microns (with a thickness tolerance of ±0.5 microns) (e.g., Figure 10) could not be obtained.

[0044] Comparative Example 3 Using a metallic lithium strip with a lithium content of 99.95%, a thickness of 5 microns, and a width of 185 mm, and a copper foil with a thickness of 8 microns (a continuous, unpatterned lithium film of 0.5 microns deposited on the surface of the copper foil), and employing an unwinding and winding device, cold rolling was performed with a controlled pressure of 100 MPa. As a result, no ultra-thin, ultra-wide lithium composite product (with wrinkles or gathers) with a uniform, continuous metallic lithium thickness of 5 microns (thickness tolerance of ±0.5 microns) was obtained.

[0045] Example 4 - Electrochemical Measurement: First, using the 5-micron ultrathin lithium composite product obtained in Example 1, it was punched out into an electrode sheet with a diameter of 15.6 cm, and a full cell was constructed using a commercially available NCM811 electrode sheet (manufactured by Hefei Kejing Co., Ltd.). 1M LiPF6, EC / DMC / EMC (1 / 1 / 1) (electrolyte manufactured by Sugi Sugi Co., Ltd.) was used as the electrolyte, and cycle measurements were performed with a charge / discharge at 0.2C. As a result, it was found that the ultrathin lithium composite product manufactured by the inventors exhibited excellent cycle performance and could stably cycle 200 times (see, for example, Figure 11).

[0046] Performance measurement An American AR-1000 general-purpose adhesive strength measuring instrument was used, with a measurement temperature of 25±5℃, a speed of 15cm / min, and a measurement angle of 120°. The adhesive strength of the ultrathin and ultrawide lithium metal composites manufactured in Examples 1-3 and Comparative Examples 1-3 was measured, and the results are shown in Table 1.

[0047] [Table 1]

[0048] As is clear from Table 1, the stress equilibrium layer effectively controls the stress between the metallic lithium and the structural layer, enabling the efficient and large-scale production of ultra-wide and ultra-thin lithium composites. Furthermore, the strong adhesion between the lithium film layer and the structural layer makes it suitable for use as a negative electrode in batteries, resulting in a long cycle life.

[0049] The above description is merely a preferred embodiment of the present invention and should not be understood as limiting the present invention. All modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should all be included within the scope of protection of the present invention.

Claims

1. A lithium composite for the anode of a lithium-ion battery, It is in the form of tape, Structural layers, A stress equilibrium layer located on at least one surface of the structural layer, having patterned metallic lithium and / or lithium alloy, and having a thickness of 0.1 to 1 μm, A rolled lithium film having a width of 185 to 1500 mm, a uniform thickness of 0.5 to 30 microns, and a thickness tolerance of within 20% of the thickness, Equipped with, The lithium film is composited with the structural layer via the stress equilibrium layer to form the lithium composite. The lithium composite is characterized in that the patterned metallic lithium and / or lithium alloy in the stress equilibrium layer is a stripe-like pattern formed of elongated or linear metallic lithium and / or lithium alloy, or an array of polygons arranged with elongated or linear metallic lithium and / or lithium alloy as sides, the width of the elongated or linear metallic lithium and / or lithium alloy is 0.5 to 5 mm, provided that the spacing distance of the stripe-like pattern is 1 to 3 mm, the array includes an array of equilateral polygons, the sides of the equilateral polygons are ≥ 3, the side length is 2 to 15 mm, and the ratio of the area of ​​the metallic lithium and / or lithium alloy equilateral polygons in the stress equilibrium layer to the area of ​​the gaps is 1.2 to 20, or optionally, the ratio of the width to the spacing distance of the striped metallic lithium and / or lithium alloy is 1 / 4 to 3.

2. The lithium composite according to claim 1, characterized in that the lithium film is continuous or discontinuous in the longitudinal direction, the length range of the metallic lithium layer area of ​​the discontinuous lithium film is 1 to 2000 mm, and the length range of the blank area is 1 to 200 mm.

3. The lithium composite according to claim 1, characterized in that the lithium film is continuous or discontinuous in the width direction, and the discontinuous portions of the discontinuous lithium film are spaced apart by 0.5 to 10 mm.

4. The aforementioned lithium alloy is an alloy of lithium with one or more elements from silicon, silver, carbon, magnesium, aluminum, indium, boron, tin, and gallium. The lithium composite according to claim 1, characterized in that the structural layer comprises metallic copper, or a single-layer or multi-layer composite of copper-organic materials, the organic material being at least one of polyethylene terephthalate, polypropylene, polyvinyl chloride, and polyimide, and the thickness of the structural layer being 3.5 microns to 20 microns.

5. A method for producing a lithium composite according to any one of claims 1 to 4, A process of forming patterned metallic lithium and / or lithium alloys on a structural layer by pressurized compounding, spraying, dipping, transfer coating, extrusion coating, scraper coating, curtain coating, screen printing, vapor deposition, or vapor phase growth, in order to obtain a stress equilibrium layer, A process to obtain a lithium composite by rolling a metallic lithium strip with a thickness of 5 to 2000 μm as a raw material and compounding it on a stress equilibrium layer, A method characterized by including the following.

6. The method according to claim 5, characterized in that the rolling pressure range is 0.1 to 150 MPa.

7. The method according to 5, wherein the rolling includes any of the following selected from cold rolling, hot rolling, compound rolling and differential periphery speed rolling, and the temperature range of the hot rolling is controlled to 60 to 120°C.

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