An ultrahigh energy density solid-state lithium metal battery and a preparation method thereof

Abstract

The application belongs to the field of power batteries, and relates to an ultrahigh-energy-density solid-state lithium metal battery and a preparation method thereof. The battery adopts a lithium metal negative electrode, a high-voltage positive electrode and a solid-state electrolyte formed by in-situ polymerization. The key of the preparation method is that: a liquid precursor solution containing an acrylic ester monomer, a plasticizer, a fluorosulfonyl activator and an initiator is injected into a battery cell, and then, under the condition of room temperature of 20-30 DEG C, the in-situ polymerization is completed after standing for 24-48 hours, so that the solid-state electrolyte is formed. The solid-state lithium metal battery prepared by the method has the advantages of uniform interface and high stability, the mass energy density of the battery is more than 600 Wh·kg ‑1 , and the battery shows excellent cycle performance and safety performance, and solves the problems of uneven interface, many side reactions and high energy consumption existing in the existing heating in-situ polymerization technology.

Description

Technical Field

[0001] This invention belongs to the field of power batteries, specifically relating to an ultra-high energy density solid-state lithium metal battery and its preparation method. Background Technology

[0002] With the rapid development of new energy vehicles, drones, and other fields, higher demands are being placed on the energy density and safety of power batteries. However, the energy density of current lithium-ion power batteries based on lithium iron phosphate or ternary cathodes and graphite anodes is already approaching the theoretical limit (350 Wh·kg⁻¹). -1 This makes it difficult to meet the demand for long-range driving. Furthermore, commercial lithium-ion batteries generally use flammable organic liquid electrolytes, posing a high risk of combustion under overcharge or abuse conditions. Therefore, simultaneously improving energy density and safety is the main challenge currently facing the development of lithium-ion batteries.

[0003] Replacing traditional electrode materials with high-capacity lithium metal anodes and high-voltage lithium-rich manganese-based cathodes, and using solid electrolytes instead of organic liquid electrolytes, is an effective way to overcome the current bottlenecks in energy density and safety of lithium batteries.

[0004] Currently, most publicly disclosed in-situ polymerization technologies for solid-state electrolytes require heating. For example, Chinese patent CN117712499A discloses a high-voltage solid-state battery that requires polymerization at 60-80 °C for 2-4 hours; Chinese patent CN119890466A discloses a method for preparing a negative electrode-free battery that requires polymerization at 60-80 °C for 2-10 hours. This heating polymerization method has significant drawbacks: firstly, uneven polymerization at the electrode / electrolyte interface leads to uneven internal resistance distribution in the battery; secondly, it easily induces lithium dendrite growth and damage to the crystal structure of the cathode material; and finally, the heating process increases the complexity of the production process and energy consumption.

[0005] Therefore, developing a solid electrolyte system capable of efficient and uniform in-situ polymerization at room temperature is of great significance for preparing solid-state lithium metal batteries with high interfacial stability, high energy density, and high safety. Summary of the Invention

[0006] The present invention aims to overcome the problems of interface inhomogeneity, numerous side reactions and high energy consumption caused by the in-situ polymerization of solid electrolytes requiring heating in the prior art, and provides an ultra-high energy density solid lithium metal battery and its preparation method. The solid electrolyte can achieve uniform polymerization at room temperature, thereby obtaining a battery product with ultra-high energy density.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing an ultra-high energy density solid-state lithium metal battery, comprising the following steps:

[0009] A battery cell is provided, the battery cell comprising a lithium metal negative electrode and a high-voltage positive electrode;

[0010] A liquid precursor solution is injected into the battery cell, the liquid precursor solution comprising acrylate monomers, plasticizers, fluorosulfonyl activators, and initiators;

[0011] The battery cell injected with the liquid precursor solution is left to stand at a temperature of 20-30 °C for 24-48 hours to allow the liquid precursor solution to undergo in-situ polymerization, forming a solid electrolyte, thereby obtaining the solid lithium metal battery.

[0012] This invention creatively introduces a fluorosulfonyl activator with a specific structure. This activator can react with trace amounts of moisture in the system to generate protonated hydrogen, activating the active substances in the carbon-carbon double bonds of the acrylate monomer, thereby efficiently initiating the polymerization reaction under mild conditions without external heating. This is completely different from the polymerization mechanism in the prior art that relies on the thermal decomposition of thermal initiators to generate free radicals.

[0013] Further, the liquid precursor solution comprises the following components in parts by weight: acrylate monomer: 1-30 parts; plasticizer: 60-98.5 parts; fluorosulfonyl activator: 3-20 parts; initiator: 0.1-3 parts.

[0014] Furthermore, the fluorosulfonyl activator is selected from at least one of methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (MDFSA), N,N-dimethylaminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide. These compounds have active fluorosulfonyl groups, which are key to initiating polymerization at room temperature.

[0015] Furthermore, the acrylate monomer is selected from at least one of methyl acrylate (MA), polyethylene glycol diacrylate (PEGDA), ethoxylated trimethylolpropane triacrylate (ETPTA), and isoprene tetraacrylate (PETEA).

[0016] Furthermore, the plasticizer is a liquid electrolyte comprising a lithium salt and an organic solvent. The lithium salt is selected from at least one of lithium difluorooxalate borate (LiDFOB) and lithium hexafluorophosphate (LiPF6); the organic solvent is selected from at least one of fluoroethylene carbonate (FEC), methyl trifluoroethyl carbonate (FEMC), and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE). This plasticizer system exhibits both high voltage stability and good ion transport capability.

[0017] Furthermore, the thickness of the lithium metal anode is 10-50 μm, and the areal loading of the high-voltage cathode is 5-15 mAh·cm³. -2 .

[0018] Furthermore, the active material of the high-voltage positive electrode is selected from at least one of lithium-rich manganese-based materials, nickel-cobalt-manganese-based materials, and lithium cobalt oxide. Lithium-rich manganese-based materials, such as Li... 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2 or single-crystal lithium-rich manganese-based materials; nickel-cobalt-manganese based materials such as LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2.

[0019] Furthermore, the initiator is azobisisobutyronitrile (AIBN).

[0020] Secondly, the present invention provides a solid lithium metal battery prepared by the above method, comprising a lithium metal negative electrode, a high-voltage positive electrode, and a solid electrolyte, wherein the solid electrolyte is a polymer-based solid electrolyte formed by in-situ polymerization, comprising an acrylate polymer matrix polymerized by a fluorosulfonyl activator, wherein the fluorosulfonyl activator is selected from at least one of 2,2-difluoro-2-(fluorosulfonyl)acetic acid methyl ester, N,N-dimethylaminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide.

[0021] The energy density of the solid-state lithium metal batteries is greater than 600 Wh·kg. -1 The highest energy density exceeds 650 Wh / kg. -1 .

[0022] When assembled into a pouch cell, the negative electrode accounts for less than 5% of the total pouch cell mass, the positive electrode accounts for more than 60% of the total pouch cell mass, and the electrolyte accounts for no more than 30% of the total pouch cell mass.

[0023] The battery casing includes, but is not limited to, one of the following: pouch battery, prismatic battery, cylindrical battery, stacked battery, and wound battery.

[0024] Advantages and beneficial effects of the present invention:

[0025] 1. This invention achieves room temperature in-situ polymerization: by utilizing the novel function of fluorosulfonyl activators, the traditional heating polymerization process is eliminated, avoiding problems such as uneven electrolyte distribution and interface deterioration caused by uneven heating.

[0026] 2. This invention improves interface stability and battery performance: The room temperature polymerization conditions are mild, which significantly reduces the side reactions at the electrode / electrolyte interface caused by high temperature, which is conducive to the formation of a uniform and stable solid electrolyte interface film, thereby inhibiting lithium dendrite growth and improving the cycle life and safety of the battery.

[0027] 3. This invention simplifies the process and reduces energy consumption: no heating equipment is required, the production process is simpler, energy consumption is lower, and it is easier to scale up production.

[0028] 4. This invention achieves ultra-high energy density: By combining an ultra-thin lithium anode, a high-load, high-voltage cathode, and an optimized electrolyte mass ratio, an energy density exceeding 650 Wh·kg⁻¹ was successfully prepared. -1 The soft-pack battery outperforms existing reports significantly. Attached Figure Description

[0029] Figure 1 This is a comparison of the infrared (FTIR) spectra of the electrolyte samples prepared in Example 1 of this invention with those in Comparative Examples 1 and 2.

[0030] Figure 2 These are macroscopic comparison photographs of the precursor solutions of Example 1 and Comparative Examples 1 and 2 of the present invention in their initial state and in their upright and inverted states after standing at 30°C for 24 hours; wherein a corresponds to Comparative Example 1, b corresponds to Comparative Example 2, and c corresponds to Example 1.

[0031] Figure 3 This is a graph showing the ionic conductivity of the SS-SS battery assembled at room temperature in Example 3 of the present invention.

[0032] Figure 4 The curve is a linear sweep voltammetry (LSV) curve obtained from the SS-Li battery assembled in Example 4 of this invention.

[0033] Figure 5 This is a leakage current test diagram of the full battery assembled in Embodiment 5 of the present invention.

[0034] Figure 6 These are comparison diagrams of the F-spectrum of X-ray photoelectron spectroscopy on the surface of lithium metal anode after cycling; where a is the F-spectrum of lithium metal surface after cycling with high-temperature polymeric electrolyte, and b is the F-spectrum of lithium metal surface after cycling with room-temperature polymeric electrolyte.

[0035] Figure 7 These are atomic force microscopy surface roughness comparison images of lithium metal anode surfaces after cycling, where a is the surface roughness image of lithium metal after cycling with high-temperature polymeric electrolyte, and b is the surface roughness image of lithium metal after cycling with room-temperature polymeric electrolyte.

[0036] Figure 8These are comparison diagrams of the Young's modulus of the interface layer on the surface of the lithium metal anode after cycling. In diagram a, the Young's modulus of the lithium metal surface after cycling with a high-temperature polymer electrolyte is shown, and in diagram b, the Young's modulus of the lithium metal surface after cycling with a room-temperature polymer electrolyte is shown.

[0037] Figure 9 These are transmission electron microscopy (TEM) comparison images of the interface layers of lithium-rich manganese-based cathode particles after cycling. In image a, the interface film of the lithium-rich manganese-based cathode particles after cycling with a high-temperature polymer electrolyte is shown, and in image b, the interface film of the lithium-rich manganese-based cathode particles after cycling with a room-temperature polymer electrolyte is shown.

[0038] Figure 10 These are comparative ultrasound transmission imaging images of pouch cells polymerized at room temperature and at high temperature. Image a shows the ultrasound transmission image of a pouch cell polymerized at high temperature, and image b shows the ultrasound transmission image of a pouch cell polymerized at room temperature.

[0039] Figure 11 This is the charge-discharge curve of the soft-pack battery prepared in Example 11 of the present invention.

[0040] Figure 12 This is the charge-discharge curve of the soft-pack battery prepared in Example 12 of the present invention.

[0041] Figure 13 This is the charge-discharge curve of the soft-pack battery prepared in Example 13 of the present invention.

[0042] Figure 14 These are the charge-discharge curves of the soft-pack battery prepared in Example 14 of this invention at different rates.

[0043] Figure 15 These are the discharge curves of the soft-pack battery prepared in Example 15 of this invention at different temperatures. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to the accompanying drawings and specific examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0045] Example 1

[0046] A method for preparing an ultra-high energy density solid-state lithium metal battery involves in-situ polymerization of high-voltage resistant monomers at room temperature induced by a fluorosulfonyl activator to prepare a solid electrolyte capable of matching high-voltage, high-capacity positive and negative electrodes. The steps are as follows:

[0047] (1) 15 mg of high-pressure resistant monomer isoprene tetraacrylate (PETEA), 67 μL of fluorosulfonyl activator methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (MDFSA), and 563 μL of plasticizer (0.85 mol / L lithium hexafluorophosphate and 0.15 mol / L lithium difluorooxalate borate dissolved in a mixed solvent composed of fluoroethylene carbonate (FEC), methyl trifluoroethyl carbonate (FEMC), and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) in a volume ratio of 3:5:2) were mixed and dissolved to form a homogeneous precursor solution 1;

[0048] (2) Mix and dissolve 10 mg of initiator azobisisobutyronitrile (AIBN) and 200 μL of plasticizer to form a homogeneous precursor solution 2;

[0049] (3) Take 20 μL of precursor solution 2 with a pipette and add it to precursor solution 1 to form homogeneous precursor solution 3. The preferred injection tool is a pipette with a volume of 100 μL.

[0050] (4) The precursor solution 3 was allowed to stand at 30 °C for 24 h to complete the polymerization.

[0051] Comparative Example 1

[0052] The difference from Example 1 is that no fluorosulfonyl activator is added, while the other conditions are the same as in Example 1.

[0053] Comparative Example 2

[0054] The difference from Example 1 is that MDFSA is replaced with trimethyl borate, while the other conditions are the same as in Example 1.

[0055] The final samples from Example 1, Comparative Example 1, and Comparative Example 2 were subjected to infrared spectroscopy testing. The test results are as follows: Figure 1 As shown. From Figure 1 It can be seen that when MDFSA was added in Example 1, the characteristic peak of the C=C double bond belonging to the PETEA polymer monomer disappeared, while in Comparative Example 1 and Comparative Example 2, the characteristic peak of the C=C double bond still existed, proving that the fluorosulfonic acid activator MDFSA can induce the electrolyte to fully polymerize at room temperature.

[0056] Example 2

[0057] Take 50 μL of precursor solution 3 from Example 1, and solutions from Comparative Example 1 and Comparative Example 2, respectively, and inject them into transparent glass vials. Comparative macroscopic images of the initial state and the upright and inverted states after standing at 30°C for 24 hours are shown below. Figure 2As shown, in the initial state, all three systems are colorless and transparent liquid phases, and can flow after being inverted. After standing at 30 °C for 24 hours, the samples of Comparative Example 1 and Comparative Example 2 still remain flowable transparent liquids. After the vials are inverted, the electrolyte flows, and no polymerization phenomenon is observed. However, the sample of Example 1 turns into a white gel. After the vials are inverted, the electrolyte cannot flow. This demonstrates that the system with added fluorosulfonyl activator has been observed to transform from a liquid to a solid gel, which directly proves that the system of the present invention has excellent gelation ability at room temperature.

[0058] Example 3

[0059] Using the precursor solution 3 freshly mixed in Example 1, with two stainless steel (SS) sheets as the positive and negative electrodes and a Celgard 2500 membrane as the separator, 50 μL of precursor solution 3 was injected to assemble an SS-SS half-cell. After assembly under 0.85 tons of pressure, the cells were allowed to stand at room temperature (25 °C) for 24 h to allow in-situ polymerization to complete. Ionic conductivity was then tested, and the results are shown below. Figure 3 ,from Figure 3 It can be seen that the room-temperature polymeric electrolyte obtained by the fluorosulfonyl activator exhibits a high ionic conductivity, which is 0.658 mS·cm at room temperature. -1 It has a room-temperature ionic conductivity close to that of a liquid electrolyte.

[0060] Example 4

[0061] An SS-Li battery was assembled using a stainless steel (SS) sheet as the positive electrode, a 14 mm diameter, 450 μm thick lithium sheet as the negative electrode, and a Celgard 2500 separator. 50 μL of the pre-mixed, un-stationed precursor solution 3 from Example 1 was injected. After encapsulation, the battery was allowed to stand at 30 °C for 24 hours. Electrochemical workstations were used to measure the voltage at 0.2 mV·s⁻¹. -1 Linear scan voltammetry (LSV) tests were performed at scan rates ranging from 2.5 to 7.0 V. The results are as follows: Figure 4 As shown, from Figure 4 It can be seen that the room temperature polymeric electrolyte obtained by the fluorosulfonyl activator exhibits high high voltage tolerance and does not show obvious oxidation peaks under a voltage condition of 6.7 V.

[0062] Example 5

[0063] CR2032 coin cells were assembled using the freshly mixed, un-stood precursor solution 3 from Example 1, with the cathode being a lithium-rich manganese-based material (Li). 1.2 Ni 0.13 Co 0.13 Mn 0.54 O2), positive electrode diameter 10 mm, loading 15 mg·cm³ -2The negative electrode was a Li sheet with a diameter of 10 mm and a thickness of 50 μm, the separator was Celgard 2500, and the amount of precursor solution 3 added was 18 μL. After the battery was assembled under a pressure of 0.85 tons, it was allowed to stand at 30 ℃ at room temperature for 24 h to complete the in-situ polymerization, resulting in a room temperature polymerized Li-LRMO battery. The assembled full cell was subjected to leakage current testing, with constant voltage testing at 0.1V intervals from 4.5V to 5.2V for 2 h, and the current change graph was obtained, as shown in the figure. Figure 5 As shown, from Figure 5 It can be seen that the room temperature polymeric electrolyte exhibits high compatibility with lithium-rich manganese-based materials, and the assembled lithium|room temperature polymeric electrolyte|lithium-rich manganese-based battery exhibits low leakage current in the voltage range of 4.6 to 5.2 V.

[0064] Example 6

[0065] The precursor solution 3, freshly mixed but not yet allowed to stand from Example 1, was used to assemble a Li-Li symmetric cell. The Li-Li symmetric cell was assembled and tested using a Li sheet with a diameter of 14 mm and a thickness of 450 μm. The amount of precursor solution 3 used was 50 μL, and the separator was Celgard 2500. After assembly under 0.85 tons of pressure, the cell was allowed to stand at 30 °C for 24 h at room temperature to allow in-situ polymerization to complete, resulting in a room-temperature polymerized Li-Li symmetric cell. Alternatively, it could be allowed to stand at 60 °C for 24 h to obtain a high-temperature polymerized Li-Li symmetric cell.

[0066] The assembled symmetrical cell was cycled, and after disassembly, X-ray photoelectron spectroscopy was used to characterize and analyze the surface F element spectral signal. For example... Figure 6 As shown, from Figure 6 As can be seen from Figure a, after cycling with a high-temperature polymeric electrolyte, the F spectrum of the lithium metal surface shows more CF components, indicating an unstable lithium metal surface layer formed by more organic components. Figure 6 As can be seen from b, the room temperature polymeric electrolyte exhibits more Li-F components, showing a stable lithium metal surface layer formed by more inorganic components.

[0067] Example 7

[0068] The Li-Li symmetric battery assembled in Example 6 was cycled, and its surface roughness was analyzed using atomic force microscopy after disassembly. Figure 7 As shown, Figure 7 As can be seen from Figure a, after cycling with a high-temperature polymeric electrolyte, lithium metal exhibits uneven lithium deposition, resulting in an unstable lithium metal surface. Figure 7 As can be seen from b, room temperature polymeric electrolytes can ensure uniform deposition of lithium metal and maintain the stability of the lithium metal surface after cycling.

[0069] Example 8

[0070] The Li-Li symmetric battery assembled in Example 6 was cycled, and its surface Young's modulus was analyzed using atomic force microscopy after disassembly. Figure 8 As shown, Figure 8 As can be seen from Figure a, after cycling with a high-temperature polymeric electrolyte, the interface layer on the lithium metal surface exhibits a lower Young's modulus. Figure 8 As can be seen from b, a more stable lithium metal interface layer can be obtained by using room temperature polymerized electrolyte, exhibiting a higher Young's modulus.

[0071] Example 9

[0072] The difference from Example 5 is that the battery was assembled under 0.85 tons of pressure and then left to stand at 60 °C for 24 h to obtain a high-temperature polymerized Li-LRMO symmetric battery.

[0073] The room-temperature polymerized Li-LRMO battery assembled in Example 5 and the high-temperature polymerized Li-LRMO symmetric battery in Example 9 were subjected to cycle testing. The batteries were charged and discharged at a rate of 0.2 C at 2-4.8 V for 10 cycles. After these cycles, the batteries were disassembled, and the lithium-rich manganese-based cathode was removed. Samples were prepared for transmission electron microscopy analysis. Figure 9 As shown, Figure 9 As can be seen in Figure a, the uneven polymerization of the high-temperature polymeric electrolyte on the cathode surface and its incompatibility during cycling lead to the formation of an uneven and relatively thick lithium-rich manganese-based interfacial film. Figure 9 Figure b shows the uniform polymerization of the room-temperature polymeric electrolyte at the interface and the stability of the cathode during cycling, achieving a uniform and thin lithium-rich manganese-based interface film.

[0074] Example 10

[0075] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 9 cm, electrolyte added amount is 1.35 g·Ah -1 .

[0076] After the pouch cells were assembled, they were allowed to stand at 20 °C for 24 h to ensure full wetting of the precursor solution, and then allowed to stand at 30 °C for 24 h to complete in-situ polymerization, resulting in room-temperature polymerized lithium-lithium-rich manganese-based solid pouch cells. The homogeneity of this polymerized pouch cells was analyzed using ultrasonic transmission mode, comparing them with heated polymerized lithium-lithium-rich manganese-based solid pouch cells obtained at 60 °C. Figure 10 As shown, Figure 10As can be seen in image a, the uneven distribution of the high-temperature polymerized electrolyte in the pouch cell is significant. Figure 10 As can be seen from b, the room temperature polymerized electrolyte can ensure uniform wetting and polymerization of the electrolyte on the positive and negative electrode surfaces, avoiding the problem of uneven distribution of gel electrolyte caused by uneven heating and volatilization of liquid phase components.

[0077] Example 11

[0078] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 The soft package was assembled using a 9-positive, 10-negative stacking method, with an electrolyte addition of 1.35 g·Ah. -1 .

[0079] After the pouch cell was assembled, it was left to stand at 20 °C for 24 h to ensure full wetting of the precursor solution, and then left to stand at 30 °C for 24 h to complete in-situ polymerization, yielding a lithium-rich manganese-based solid pouch cell. The cell was cycled twice at a rate of 0.1 C (1 C = 300 mA·g). -1 With a voltage range of 2 – 4.8 V, the actual energy density is 655 Wh·kg. -1 The charge / discharge curves are as follows: Figure 11 As shown.

[0080] Example 12

[0081] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 The soft package was assembled using a 10 positive and 11 negative stacking method, with an electrolyte addition of 1.45 g·Ah. -1 .

[0082] After the pouch cells were assembled, they were left to stand at 20 °C for 24 hours to ensure full wetting of the precursor solution, and then left to stand at 30 °C for 24 hours to complete in-situ polymerization, yielding lithium-rich manganese-based solid pouch cells. After activation, the cells were cycled twice at a rate of 0.1 C (1 C = 300 mA·g). -1With a voltage range of 2 – 4.6 V, the actual energy density is 650 Wh·kg⁻¹. -1 The charge / discharge curves are as follows: Figure 12 As shown.

[0083] Example 13

[0084] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 The soft package was assembled using a 6-positive, 7-negative stacking method, with an electrolyte addition of 1.35 g·Ah. -1 .

[0085] After the pouch cell was assembled, it was left to stand at 20 °C for 24 h to ensure full wetting of the precursor solution, and then left to stand at 30 °C for 24 h to complete in-situ polymerization, resulting in a lithium-rich manganese-based solid pouch cell. The cell was cycled twice at a rate of 0.05 C (1 C = 300 mA·g). -1 With a voltage range of 2 – 4.8 V, the actual energy density is 640 Wh·kg⁻¹. -1 The charge / discharge curves are as follows: Figure 13 As shown.

[0086] Example 14

[0087] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 The soft package was assembled using a 6-positive, 7-negative stacking method, with an electrolyte addition of 1.35 g·Ah. -1 .

[0088] After the pouch cell was assembled, it was left to stand at 20 °C for 24 h to ensure full wetting of the precursor solution, and then left to stand at 30 °C for 24 h to complete in-situ polymerization, yielding a lithium-rich manganese-based solid pouch cell. The battery was cycled at different rates (1 C = 300 mA·g). -1 The voltage range is 2 – 4.8 V, and the results are as follows: Figure 14 As shown, the actual energy density is 640 Wh·kg. -1 (0.05 C), 602 Wh·kg-1 (0.1 C).

[0089] Example 15

[0090] Battery assembly was performed using the untreated precursor solution 3 from Example 1. The assembled pouch cell used lithium metal as the negative electrode (50 μm) and lithium-rich manganese-based material as the positive electrode (10 mAh·cm⁻¹). -2 PE is used as the separator in the assembly of pouch cells, with a positive electrode size of 5.8 mm. 8.8 cm, negative electrode size is 6 The soft package was assembled using a 10 positive and 11 negative stacking method, with an electrolyte addition of 1.35 g·Ah. -1 .

[0091] After the pouch cell was assembled, it was left to stand at 20 °C for 24 h to ensure full impregnation of the precursor solution, and then left to stand at 30 °C for 24 h to complete in-situ polymerization, yielding a lithium-rich manganese-based solid pouch cell. The battery was cycled at a rate of 0.05 C (1 C = 300 mA·g). -1 The voltage range was 2–4.8 V. After two activation cycles, charge and discharge were performed at different temperatures to obtain discharge curves at different temperatures. The actual discharge energy density was 634 Wh·kg⁻¹. -1 (40 ℃), the actual energy density is still 438 Wh·kg under low temperature conditions of 0 ℃. -1 The discharge curve is as follows Figure 15 As shown.

[0092] The above embodiments fully demonstrate that the present invention successfully achieves room-temperature in-situ polymerization of acrylate-based solid electrolytes by introducing a fluorosulfonyl activator. The solid-state lithium metal battery prepared by this method has outstanding advantages such as uniform and stable interface, ultra-high energy density, good cycle performance, high safety, and simple process.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an ultra-high energy density solid-state lithium metal battery, characterized in that, Includes the following steps: A battery cell is provided, the battery cell comprising a lithium metal negative electrode and a high-voltage positive electrode; A liquid precursor solution is injected into the battery cell. The liquid precursor solution contains acrylate monomers, a plasticizer, a fluorosulfonyl activator, and an initiator. The fluorosulfonyl activator is selected from at least one of 2,2-difluoro-2-(fluorosulfonyl)acetic acid methyl ester, N,N-dimethylaminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide. The fluorosulfonyl activator reacts with trace amounts of water in the system to generate protonated hydrogen, activating the active substances of the carbon-carbon double bonds in the acrylate monomers, and initiating a polymerization reaction under mild conditions without external heating. The battery cell injected with the liquid precursor solution is left to stand at a temperature of 20-30°C for 24-48 hours to allow the liquid precursor solution to undergo in-situ polymerization, forming a solid electrolyte, thereby obtaining the solid lithium metal battery.

2. The preparation method according to claim 1, characterized in that, The liquid precursor solution comprises the following components in parts by weight: Acrylate monomer: 1-30 parts; Plasticizer: 60-98.5 parts; Fluorosulfonyl activator: 3-20 parts; Initiator: 0.1-3 parts.

3. The preparation method according to claim 1 or 2, characterized in that, The acrylate monomer is selected from at least one of methyl acrylate, polyethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, and isoprene tetraacrylate.

4. The preparation method according to claim 1 or 2, characterized in that, The plasticizer is a liquid electrolyte containing lithium salt and organic solvent; the lithium salt is selected from at least one of lithium difluorooxalate borate and lithium hexafluorophosphate; the organic solvent is selected from at least one of fluoroethylene carbonate, methyl trifluoroethyl carbonate, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.

5. The preparation method according to claim 1, characterized in that, The thickness of the lithium metal anode is 10-50 μm, and the areal loading of the high-voltage cathode is 5-15 mAh·cm⁻¹. -2 .

6. The preparation method according to claim 1, characterized in that, The active material of the high-voltage positive electrode is selected from at least one of lithium-rich manganese-based materials, nickel-cobalt-manganese-based materials, and lithium cobalt oxide.

7. The preparation method according to claim 1, characterized in that, The initiator is azobisisobutyronitrile.

8. A solid-state lithium metal battery prepared by the preparation method according to any one of claims 1-7, characterized in that, The device includes a lithium metal anode, a high-voltage cathode, and a solid electrolyte. The solid electrolyte is a polymer-based solid electrolyte formed by in-situ polymerization, which contains an acrylate polymer matrix polymerized by a fluorosulfonyl activator. The fluorosulfonyl activator is selected from at least one of 2,2-difluoro-2-(fluorosulfonyl)acetic acid methyl ester, N,N-dimethylaminosulfonyl fluoride, and 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide.

9. The solid-state lithium metal battery according to claim 8, characterized in that, The energy density of the solid-state lithium metal batteries is greater than 600 Wh·kg. -1 The highest energy density exceeds 650 Wh·kg. -1 .

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