A solid-state fluorine ion block battery and a non-welding tab press forming preparation method thereof

Abstract

The application discloses a kind of solid fluorine ion block batteries and its no-welding tab compression forming preparation method, belong to electrochemical energy storage device technical field.The battery is sequentially stacked by current collector, anode sheet, electrolyte sheet, cathode sheet, current collector, and is once formed into dense block by 100-500 MPa isostatic pressing;Positive and negative electrodes are directly led out by integrated electrode column at upper and lower ends, and the tab welding is cancelled.Forming temperature room temperature-250 o C, monomer size can be enlarged to 3x3 cm 2 , 3x4 cm 2 , 3.5x4.5 cm 2 , 4x5 cm 2 The obtained block battery shows excellent fluorine ion battery performance.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage device technology, specifically to a scalable solid-state fluorine-ion bulk battery and its one-time compression molding preparation method; the battery is suitable for pressures of 100–500 MPa and temperatures from room temperature to 250°C. o C is suitable for wide temperature range operation, especially for large-capacity single cells such as 3×3 cm², 3×4 cm², 3.5×4.5 cm², and 4×5 cm². Background Technology

[0002] With the rapid development of portable electronic devices and electric vehicles, the demand for high-energy-density and high-safety energy storage devices is increasing. Fluorine-ion batteries, as a new type of electrochemical energy storage device, have advantages such as high theoretical energy density (up to 500 Wh / kg or more), good safety, and abundant raw materials in the Earth's crust, and are considered to be a new generation of energy storage technology with great development potential.

[0003] However, existing fluoride-ion batteries are still at the coin cell prototype stage (diameter ≤ 20 mm), and there is still a huge gap to bridge before achieving Ah-level engineering scale-up. Traditional solid-state pouch batteries generally use polymer films (such as PVDF-HFP / PEO) as the electrolyte substrate, prepared through a coating-drying-hot-pressing process. [Chen, G., Zhang, F., Zhou, Z. et al.: A Flexible Dual-Ion Battery Based on PVDF-HFP-Modified Gel Polymer Electrolyte with Excellent Cycling Performance and Superior Rate Capability. Advanced Energy Materials 8 (2018).] These polymer films exhibit good flexibility and adhesion in liquid or gel systems, but they suffer from the following inherent drawbacks when used with solid fluoride-ion powder systems: 1. Membrane structures cannot withstand isostatic pressures of 100–500 MPa; under high pressure, polymer creep leads to membrane rupture and delamination. 2. The polymer film and the rigid fluorinated powder have a large difference in elastic modulus, a low proportion of interfacial point contact, and discontinuous ion channels; 3. A blank aluminum-plastic film needs to be reserved in the electrode tab welding area, as the active area loss is >30%, resulting in a decrease in energy density; 4. Aluminum-plastic film edge sealing at high temperatures (>150°C) o C) Delamination is likely, and the sealing failure temperature window is lower than the operating temperature of solid-state fluorine-ion batteries (160–250°C). o C).

[0004] In addition, the room temperature ionic conductivity of solid fluoride ion electrolytes is generally below 10. -4 S cm -1 High interface impedance and short cycle life further exacerbate the difficulty of scale-up. Therefore, developing a new bulk battery structure that is weld-free, highly dense, has a wide temperature range, and can be molded in one piece has become a key breakthrough for realizing the transition of fluoride-ion batteries from "laboratory coin cells" to "engineered large-capacity batteries". Summary of the Invention

[0005] This invention addresses the problems of electrode capacity reduction, uneven stress, cracking, and sealing failure caused by scaling up existing solid-state fluoride-ion battery pouch cells. It provides a bulk battery with weld-free electrodes, high density, wide temperature range, and scalable design, along with its one-time pressing molding method.

[0006] Firstly, the object of the present invention is to provide a method for preparing a bulk battery, wherein the bulk battery includes a cathode, an electrolyte, an anode, and a current collector, and is specifically prepared according to the following steps: (1) Cathode preparation: Weigh metal fluoride powder, electrolyte powder and electronic conductive agent according to a certain mass ratio, grind and mix them, and press the cathode sheet under a certain pressure; (2) Anode preparation: Weigh low reduction potential metal (or metal / metal fluoride) powder, electrolyte powder and conductive agent according to a certain mass ratio, grind and mix them, and press the anode sheet under a certain pressure; (3) Preparation of electrolyte sheets: Weigh a certain mass of electrolyte powder and press it into electrolyte sheets under a certain pressure; (4) Block pressing: The current collector, anode plate, electrolyte plate, cathode plate and current collector are stacked in sequence and formed into a dense block in a special mold by isostatic pressing to obtain a block battery cell; (5) Tooling assembly: The bulk battery cells are placed into a special tooling for assembly to obtain a fluorine-ion battery.

[0007] Preferably, the metal fluoride in step (1) includes any one or a combination of at least two of copper fluoride, cuprous fluoride, iron fluoride, ferrous fluoride, manganese fluoride, bismuth fluoride, lead fluoride, magnesium fluoride, calcium fluoride, and tin fluoride, with copper fluoride being the most preferred.

[0008] Preferably, the low reduction potential metal powder mentioned in step (2) can be lanthanum powder, lead powder, zinc powder, tin powder, bismuth powder, aluminum powder, cerium powder, or magnesium powder. If lanthanum powder, lead powder, cerium powder, or magnesium powder is selected, it is preferably a mixture of their metal / metal fluoride powders (1:1). Preferably, the mass ratio described in steps (1) and (2) can be 80:10:10, 70:20:10, 60:30:10, 50:40:10, 40:50:10, 30:50:20 or 30:60:10, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0009] Preferably, the conductive agent described in steps (1) and (2) includes any one or a combination of at least two of Ketjen black, acetylene black, graphite, activated carbon, carbon nanotubes, and Super P, with Ketjen black being the most preferred.

[0010] Preferably, the electrolyte powder described in steps (1), (2) and (3) includes any one or a combination of at least two of lanthanum fluoride, calcium fluoride, lead fluoride, barium fluoride, tin fluoride, strontium fluoride, ammonium fluoride and cesium fluoride, preferably a combination of ammonium fluoride and tin fluoride.

[0011] Preferably, the pressure described in steps (1), (2) and (3) can be 1 t, 2 t, 3 t, 4 t, 5 t, 6 t, 7 t, 8 t, 9 t or 10 t, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0012] Preferably, the mass of the electrolyte powder in step (3) is 2.0-4.0 g, which can be 2.0 g, 2.5 g, 3.0 g, 3.5 g or 4.0 g, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0013] Preferably, the current collector in step (4) can be aluminum foil, carbon-coated aluminum foil, copper foil, carbon-coated copper foil, titanium foil, silver foil, gold foil, platinum sheet or carbon paper, preferably carbon-coated aluminum foil.

[0014] Preferably, the pressure in step (4) is 100-500 MPa, which is greater than the pressure selected in steps (1), (2) and (3) so as to facilitate better pressing and molding.

[0015] Preferably, the internal dimensions of the mold in step (4) can be 3×3 cm. 2 3×4 cm 2 3.5 × 4.5 cm 2 4×5 cm 2 etc., preferably 3×3 cm 2 .

[0016] Preferably, the thickness of the bulk battery cell in step (4) is approximately 1.0-1.5 mm.

[0017] Preferably, the positive and negative electrodes of the tooling described in step (5) are directly led out from the electrode posts at the upper and lower ends.

[0018] Secondly, a fluoride-ion battery is provided, wherein the fluoride-ion battery is prepared by the above-described preparation method, characterized in that: (1) Integrated block structure, which is formed by pressing together current collector, anode plate, electrolyte plate, cathode plate and current collector; (2) The positive and negative electrodes are led out from the electrode posts at the top and bottom ends, and there is no need to weld the electrode tabs; (3) Capable of operating at pressures of 100-500 MPa and RT-250 o Stable operation within the temperature range of C; (4) It has dimensions of 3×3, 3×4, 3.5×4.5, and 4×5 cm. 2 Enlarged dimensions for projects such as engineering.

[0019] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0020] Compared with the prior art, the present invention has the following advantages: 1. This invention prepares fluoride-ion bulk batteries by a one-time compression molding method, which significantly enhances the density of the electrolyte and improves the utilization rate of the active area of ​​the electrodes and electrolyte; 2. This invention uses positive and negative electrodes led out from the upper and lower electrode posts, eliminating the need for traditional electrode tab welding, simplifying the process, and improving reliability; 3. This invention ensures uniform pressure distribution in large-size batteries through isostatic pressing technology and structural optimization, thus avoiding stress concentration and crack formation.

[0021] 4. Through tooling design, this invention produces fluorine-ion batteries that can withstand pressures of 100-500 MPa and RT-250. o It operates stably within a temperature range of C, adapting to various harsh application environments. Attached Figure Description

[0022] Figure 1 Schematic diagram of a bulk battery structure (including integrated electrode posts) Figure 2 Morphology and elemental distribution of copper fluoride cathode composite Figure 3 Electrolyte morphology and elemental distribution of a mixture of ammonium fluoride and tin fluoride Figure 4 The first three charge-discharge curves of Example 1 Figure 5Cycle life and coulombic efficiency diagram of Example 1 Figure 6 Cycle life and coulombic efficiency diagram of Example 4 Detailed Implementation The present invention will now be described in detail with reference to the accompanying drawings and embodiments: Example 1: 3 cm × 3 cm block battery (1) Cathode preparation: 90 mg of copper fluoride powder, 180 mg of ammonium fluoride and tin fluoride (1:2) mixed electrolyte powder and 30 mg of Ketjen black were weighed and ground according to the mass ratio of 3:6:1, and the cathode was pressed under a pressure of 5 t. (2) Preparation of anode sheet: Weigh 200 mg of lead powder / lead fluoride (1:1) powder, 250 mg of ammonium fluoride and tin fluoride (1:2) mixed electrolyte powder and 50 mg of Ketjen black in a mass ratio of 4:5:1, grind and mix them, and press the anode sheet under a pressure of 5 t; (3) Preparation of electrolyte sheets: Weigh 2.5 g of ammonium fluoride and tin fluoride (1:2) mixed electrolyte powder and press the electrolyte sheets under a pressure of 6 t; (4) Block pressing: The carbon-coated aluminum foil current collector, anode sheet, electrolyte sheet, cathode sheet and carbon paper current collector are stacked in sequence and formed into a dense block in a special mold under isostatic pressing at a pressure of 200 MPa to obtain a block battery cell. (5) Tooling assembly: Place the bulk battery cells onto the attached... Figure 1 The fluorine-ion battery is obtained by assembling the components in the tooling shown.

[0023] As attached Figure 2 As shown, the cathode composite material exhibits a particle morphology of approximately 1 micrometer, with carbon, nitrogen, fluorine, tin, and copper components uniformly distributed, indicating that the composite material is uniformly mixed. (See attached image.) Figure 3 The morphology of the ammonium fluoride and tin fluoride mixed electrolyte powder shown exhibits a micron-sized particle morphology, with nitrogen, fluorine, and tin elements uniformly distributed within the particles, indicating that the material is uniformly mixed.

[0024] The bulk fluorine-ion battery prepared in Example 1 was placed in an 80°C container. o In a C-type oven, constant current charge-discharge tests were performed using a blue dot tester at a pressure of 200 MPa. The test current density was 10 mA / g, and the voltage window was -0.3 to 1.5 V. (See attached image.) Figure 4As shown, this battery exhibits a high initial discharge capacity of 128.6 mAh / g, a corresponding charge capacity of 96 mAh / g, and an initial coulombic efficiency of 75%. In the second cycle, it demonstrates discharge / charge capacities of 82.6 / 78 mAh / g. In the third cycle, the discharge / charge capacities are 75 / 73.2 mAh / g, demonstrating excellent electrochemical performance. (See attached image.) Figure 5 As shown, after 20 cycles, the reversible capacity is still 54.8 mAh / g, demonstrating excellent cycling performance.

[0025] Example 2: 3 cm × 3 cm block battery The operation method is the same as in Example 1, except that the metal fluoride is bismuth fluoride.

[0026] Example 3: 3 cm × 3 cm block battery The operation method is the same as in Example 1, except that the anode sheet is prepared using tin powder.

[0027] Example 4: 3 cm × 4 cm block battery Differences from Example 1: The cathode sheet was prepared by weighing 90 mg of ferrous fluoride powder, 180 mg of barium fluoride and tin fluoride (1:1) mixed electrolyte powder, and 30 mg of Ketjen black in a mass ratio of 3:6:1, grinding and mixing them, and pressing the cathode sheet under a pressure of 5 t; the electrolyte sheet was prepared by weighing 3.0 g of ammonium fluoride and tin fluoride (1:2) mixed electrolyte powder, and pressing the electrolyte sheet under a pressure of 6 t. The bulk fluorine-ion battery prepared in Example 4 was placed in 150... o In a C-type oven, constant current charge-discharge tests were performed using a blue dot tester at a pressure of 500 MPa. The test current density was 8 mA / g, and the voltage window was -0.6 to 0.8 V. (See attached image.) Figure 6 As shown, this battery exhibits a high initial discharge capacity of 255.5 mAh / g, a corresponding charge capacity of 202.8 mAh / g, and an initial coulombic efficiency of 79.35%. After 20 cycles, it retains a reversible capacity of 76.6 mAh / g, demonstrating excellent cycling performance.

[0028] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for preparing a solid-state fluorine ion bulk battery by welding-free tab pressing, characterized in that, Includes the following steps: (1) Cathode preparation: Weigh metal fluoride powder, electrolyte powder and conductive agent according to the mass ratio (30–60): (30–60): 10, grind and mix them, and press them into cathode sheets under a pressure of 1–10 t; (2) Preparation of anode sheet: Weigh low reduction potential metal or metal / metal fluoride mixed powder, electrolyte powder and conductive agent according to the mass ratio (30–60): (30–60): 10, grind and mix them and press them into anode sheet under a pressure of 1–10 t; (3) Preparation of electrolyte tablets: Weigh 2.0–4.0 g of electrolyte powder and press it into electrolyte tablets under a pressure of 1–10 t; (4) Bulk pressing: The current collector, anode plate, electrolyte plate, cathode plate and current collector are stacked in sequence, placed in a mold, and subjected to isostatic pressing at 100–500 MPa and room temperature to 250°C. o C is then formed into a dense bulk battery cell; (5) Tooling assembly: The bulk battery cells are installed into a special tooling, and the positive and negative electrodes are directly led out from the integrated electrode posts at the top and bottom ends without welding the electrode tabs, thus obtaining a solid fluoride ion bulk battery.

2. The method according to claim 1, characterized in that: The metal fluoride in step (1) is selected from at least one of copper fluoride, cuprous fluoride, iron fluoride, ferrous fluoride, manganese fluoride, bismuth fluoride, lead fluoride, magnesium fluoride, calcium fluoride, and tin fluoride, with copper fluoride being preferred.

3. The method according to claim 1, characterized in that: The low reduction potential metal in step (2) is selected from at least one of lanthanum, lead, zinc, tin, bismuth, aluminum, cerium, and magnesium, or a mixed powder composed of the metal and its fluoride in a 1:1 mass ratio.

4. The method according to claim 1, characterized in that: The electrolyte powder in steps (1)–(3) is selected from any one or at least two combinations of lanthanum fluoride, calcium fluoride, lead fluoride, barium fluoride, tin fluoride, strontium fluoride, ammonium fluoride, and cesium fluoride, preferably a mixture of ammonium fluoride and tin fluoride in a mass ratio of 1:

2.

5. The method according to claim 1, characterized in that: The conductive agent in steps (1)–(3) is selected from at least one of Ketjen black, acetylene black, graphite, activated carbon, carbon nanotubes, and Super P, with Ketjen black being preferred.

6. The method according to claim 1, characterized in that: The internal dimensions of the mold in step (4) are 3×3 cm², 3×4 cm², 3.5×4.5 cm² or 4×5 cm², and the thickness of the block battery cell is 1.0–1.5 mm.

7. The method according to claim 1, characterized in that: Step (4): Isostatic pressing pressure 200–500 MPa, holding time 5–30 min; molding temperature 80–250 °C o C.

8. The method according to claim 1, characterized in that: The current collector in step (4) is selected from aluminum foil, carbon-coated aluminum foil, copper foil, carbon-coated copper foil, titanium foil, platinum sheet or carbon paper, and the materials of the upper and lower current collectors can be the same or different.

9. A solid-state fluorine-ion bulk battery, characterized in that: Prepared by any one of claims 1–8, comprising: (a) An integrated block structure, formed by pressing together current collector, anode plate, electrolyte plate, cathode plate, and current collector; (b) The positive and negative electrodes are led out through integrated electrode posts at the top and bottom, without welded electrode tabs; (c) At pressures of 100–500 MPa and room temperature of –250 o Stable operation within the temperature range of C; (d) Individual unit size 3×3 cm², 3×4 cm², 3.5×4.5 cm² or 4×5 cm², thickness 1.0–1.5 mm.

10. The solid-state fluorine-ion bulk battery according to claim 9, characterized in that: Initial discharge capacity ≥128mAh / g (10 mA / g, 80) o C) or ≥255 mAh / g (8 mA / g, 150 o C), Capacity retention ≥42% after 20 cycles (80) o C) or ≥30% (150) o C).

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