Preparation method of 3D fiber reticular solid electrolyte

Abstract

The invention discloses a preparation method of a 3D fiber mesh solid electrolyte, which comprises the following steps: sequentially dissolving 8-16 mg of aluminum chloride, 260-520 mg of lanthanum nitrate, 25-50 mg of lithium chloride and 120-240 mg of zirconium chloride in 10-20 mL of deionized water, and successfully synthesizing the 3D fiber mesh Li < 6.85 > La < 2.3 > Zr < 2 > Al < 0.31 > O < 11.3 > solid electrolyte by using template induction and high-temperature calcination technologies. The microfibers are interwoven, and the unique 3D fiber network structure can improve the interfacial effect of the traditional solid electrolyte, effectively enhance the ionic conductivity of a sample, and show excellent cycle stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials and their applications, and specifically relates to a 3D fiber mesh Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Method for preparing solid electrolyte. Background Art

[0002] As the most promising energy storage system, lithium batteries have developed rapidly in recent years, bringing unprecedented changes to portable electronic devices, promoting the development of smart devices such as mobile phones, laptops, and home robots, and providing strong support for the popularization of electric vehicles [Zhang S, Ueno K, Dokko K, et al. Recent advances in electrolytes for lithium-sulfur batteries. Advanced Energy Materials, 2015, 5(16): 1500117; Janek J, Zeier W G. A solid future for battery development. Nature Energy, 2016, 1(9): 1-4.]. It has also reduced people's extreme demand for fossil energy such as oil and improved the climate problem caused by carbon dioxide emissions. It has the advantages of high energy density, long cycle life, and wide operating temperature range, and occupies a dominant position in the energy storage market. However, current rechargeable lithium batteries generally use flammable and volatile liquid electrolytes, so during overcharging or abuse operation, especially in large-scale applications, it may cause leakage and fire hazards, which is easy to cause safety hazards, seriously restricting its widespread application in electric vehicles.

[0003] Compared with traditional lithium-ion batteries, solid-state batteries have attracted much attention due to their features such as no need for thermal management systems, better performance at extreme temperatures, faster charging speeds, longer life cycles, and higher safety [Hu Y S. Batteries: getting solid. Nature Energy, 2016, 1(4): 1-2; Crowther O, West AC. Effect of electrolyte composition on lithium dendrite growth. Journal of the Electrochemical Society, 2008, 155(11): A806-A811.]. Solid-state batteries can undergo 8,000 to 10,000 charging cycles, while lithium-ion batteries are expected to undergo 1,500 to 2,000 charging cycles. Solid-state batteries are inherently safer than lithium-ion batteries, with higher impact resistance and lower risk of fire. However, solid-state battery technology is still in the development stage, although many related works have been reported [Zhou D, Shanmukaraj D, TkachevaA, et al. Polymer electrolytes for lithium-based batteries: advances and prospects[J]. Chem, 2019, 5(9): 2326-2352; Yue L, Ma J, Zhang J, et al. Allsolid-state polymer electrolytes for high-performance lithium-ion batteries[J]. Energy Storage Materials, 2016, 5:139-164; Sun C, Liu J, Gong Y, et al. Recent advances in all-solid-state rechargeable lithium batteries[J]. NanoEnergy, 2017, 33: 363-386.]. However, it is still necessary to further explore more optimized structures to meet the actual needs in terms of lithium ion conductivity and lithium dendrite suppression ability, so as to improve the cycle stability of solid-state batteries. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a 3D fiber mesh solid electrolyte in order to improve the excellent cycle stability of the solid electrolyte material.

[0005] A method for preparing a 3D fiber mesh solid electrolyte, comprising:

[0006] 1) Dissolve 8 to 16 mg aluminum chloride, 260 to 520 mg lanthanum nitrate, 25 to 50 mg lithium chloride, and 120 to 240 mg zirconium chloride in 10 to 20 mL deionized water.

[0007] 2) The mixed solution obtained in step (1) and the cut lens cleaning paper are placed in a high pressure reactor and allowed to react at 10 to 50 MPa for 10 to 24 hours before use.

[0008] 3) Take out the lens paper in the reactor of step (2) and place it in a beaker. Then, add 400 ~ 800 μL of 25 mg / mL dopamine and 200 ~ 500 μL of ammonia water to its surface in sequence and let it react for 8 ~ 12 h. Take out the lens paper and freeze-dry it at -50℃ for 36 ~ 72 h for later use.

[0009] 4) The sample obtained in step (3) is placed in a muffle furnace and calcined at 800-900°C for 2-3 hours in an air atmosphere to obtain a 3D fiber mesh Li6.85La2.3Zr2Al0.31O11.3 solid electrolyte material.

[0010] 8 mg of aluminum chloride, 260 mg of lanthanum nitrate, 25 mg of lithium chloride, and 120 mg of zirconium chloride described in step 1)

[0011] 16 mg of aluminum chloride, 520 mg of lanthanum nitrate, 50 mg of lithium chloride and 240 mg of zirconium chloride described in step 1).

[0012] 12 mg of aluminum chloride, 390 mg of lanthanum nitrate, 38 mg of lithium chloride and 90 mg of zirconium chloride described in step 1).

[0013] The present invention provides a method for preparing a 3D fiber mesh solid electrolyte. 8 to 16 mg aluminum chloride, 260 to 520 mg lanthanum nitrate, 25 to 50 mg lithium chloride and 120 to 240 mg zirconium chloride are sequentially dissolved in 10 to 20 mL deionized water, and a 3D fiber mesh solid electrolyte is successfully synthesized by using template induction and high temperature calcination technology. 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte. The microfibers are interwoven with each other, and their unique 3D fiber mesh structure can improve the interface effect of traditional solid electrolytes, effectively enhance the ionic conductivity of the sample, and show excellent cycle stability.

[0014] The present invention has the following advantages:

[0015] 1. The 3D fiber mesh solid electrolyte obtained by the present invention exhibits vertical / horizontally anisotropic lithium ion conduction characteristics, which can significantly homogenize the electric field distribution at the interface between the solid electrolyte and the lithium negative electrode, promote uniform lithium ion stripping and deposition, and effectively improve the ability to inhibit lithium dendrites.

[0016] 2. The 3D fiber mesh solid electrolyte material prepared by the method of the present invention has excellent cycle stability and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The Li prepared by the present invention 6.85 La 2.3 Zr2Al 0.31 O 11.3 Scanning electron microscope image of the solid electrolyte.

[0018] Figure 2 The Li prepared by the present invention 6.85 La 2.3 Zr2Al 0.31 O 11.3 Scanning image of the solid electrolyte surface.

[0019] Figure 3 The Li prepared by the present invention 6.85 La 2.3 Zr2Al 0.31 O 11.3 Cycling performance diagram of solid electrolyte symmetric battery.

[0020] Figure 4 The Li prepared by the present invention 6.85 La 2.3 Zr2Al 0.31 O 11.3 Charge and discharge cycle curves of solid electrolytes. DETAILED DESCRIPTION

[0021] Embodiment 1:

[0022] Dissolve 8 mg aluminum chloride, 260 mg lanthanum nitrate, 25 mg lithium chloride, and 120 mg zirconium chloride in 10 mL deionized water. Then add the cut lens cleaning paper and place it in a high pressure reactor and react at 10 MPa for 24 h. Take out the lens cleaning paper, place it in a beaker, and add 400 μL of 25 mg mL -1 Dopamine and 200 μL of ammonia water were added dropwise to the surface of the lens cleaning paper and allowed to react for 12 h. oC for 36 h, and then placed in a muffle furnace at 800 o C was calcined in air atmosphere for 3 h to obtain Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte materials.

[0023] Embodiment 2:

[0024] Dissolve 16 mg aluminum chloride, 520 mg lanthanum nitrate, 50 mg lithium chloride, and 240 mg zirconium chloride in 20 mL deionized water. Then add the cut lens cleaning paper and place it in a high pressure reactor at 50 MPa for 12 h. Take out the lens cleaning paper, place it in a beaker, and add 800 μL of 25 mg mL -1 Dopamine and 500 μL ammonia water were added dropwise to the surface of the lens cleaning paper and allowed to react for 8 h. o After freeze drying for 72 h, the samples were placed in a muffle furnace at 900 °C in an air atmosphere. o C was calcined for 2 h to obtain Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte materials.

[0025] Embodiment 3:

[0026] Dissolve 12 mg aluminum chloride, 390 mg lanthanum nitrate, 38 mg lithium chloride, and 90 mg zirconium chloride in 15 mL deionized water. Then add the cut lens cleaning paper and place it in a high pressure reactor and react at 30 MPa for 15 h. Take out the lens cleaning paper, place it in a beaker, and add 600 μL 25 mg mL -1 Dopamine and 400 μL of ammonia water were added dropwise to the surface of the lens cleaning paper and allowed to react for 10 h. o After freeze drying for 60 h, the samples were placed in a muffle furnace at 850 °C under air atmosphere. o C was calcined for 2 h to obtain Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte materials.

[0027] Example 4 Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte materials for electrochemical testing of lithium-ion battery solid electrolytes

[0028] 1. Preparation of electrodes: lithium iron phosphate as active material, acetylene black as conductive agent, polyvinylidene fluoride (PVDF) as binder are mixed and ground evenly in a certain ratio (active material, conductive agent, polyvinylidene fluoride are 78:10:10), and then a small amount of NMP is added as a dispersant to prepare a uniform slurry. Subsequently, the slurry is applied on a 12 mm copper foil and 90 o C was vacuum dried for 12 h to obtain the positive electrode sheet.

[0029] Assembly of button cells: 2025 button cells were assembled in an argon-filled glove box (water and oxygen values ​​were less than 0.1 ppm), with lithium sheets as counter electrodes and Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte material, matched with the working electrode, is assembled into a button battery.

[0030] Symmetrical battery assembly: 2025-size button cells were used in a glove box filled with Ar. Two lithium sheets were placed on both sides of the solid electrolyte membrane for assembly.

[0031] 2. Electrochemical test

[0032] The discharge-charge cycles were performed in the voltage range of 2.0–4.2 V on a battery tester (CT2001A, LAND, China). Cyclic voltammetry (CV) was performed on a CHI760E electrochemical workstation at 0.1 mV s -1 The scan rate was between 2.0 and 4.2 V, and the electrochemical impedance spectroscopy (EIS) was obtained on a CHI760E electrochemical workstation with a frequency range of 100 kHz to 0.01 Hz and an amplitude of 5 mV s -1 .

[0033] Long-term stripping / deposition tests show that the solid electrolyte can be stably cycled for 700 h without short circuit. In addition, the solid-state battery assembled with commercial lithium iron phosphate as the positive electrode and lithium metal as the negative electrode exhibits excellent electrochemical performance at a current density of 0.2 A g -1 , solid-state batteries achieve a stable 150 mAh g -1 And there is no obvious capacity decay after 200 stable cycles, which proves the high electrochemical stability of solid-state batteries.

Claims

1. A method for preparing a 3D fiber mesh solid electrolyte, comprising: 1) Dissolve 8 ~ 16 mg aluminum chloride, 260 ~ 520 mg lanthanum nitrate, 25 ~ 50 mg lithium chloride, and 120 ~ 240 mg zirconium chloride in 10 ~ 20 mL deionized water. 2) placing the mixed solution obtained in step (1) and the cut lens cleaning paper in a high pressure reactor, and reacting at 10 to 50 MPa for 10 to 24 hours; 3) Take out the lens paper in the reactor of step (2) and place it in a beaker. Then, add 400 ~ 800 μL 25 mg mL-1 dopamine and 200 ~ 500 μL ammonia water to its surface in sequence and let it react for 8 ~ 12 h. Take out the lens paper and freeze-dry it at -50℃ for 36 ~ 72 h; 4) The sample obtained in step (3) was placed in a muffle furnace and calcined at 800-900 °C for 2-3 h in an air atmosphere to obtain a 3D fiber mesh Li 6.85 La 2.3 Zr2Al 0.31 O 11.3 Solid electrolyte materials.

2. A method for preparing a 3D fiber mesh solid electrolyte according to claim 1, characterized in that: 8 mg of aluminum chloride, 260 mg of lanthanum nitrate, 25 mg of lithium chloride and 120 mg of zirconium chloride described in step 1).

3. A method for preparing a 3D fiber mesh solid electrolyte according to claim 1, characterized in that: 16 mg of aluminum chloride, 520 mg of lanthanum nitrate, 50 mg of lithium chloride and 240 mg of zirconium chloride described in step 1).

4. A method for preparing a 3D fiber mesh solid electrolyte according to claim 1, characterized in that: 12 mg of aluminum chloride, 390 mg of lanthanum nitrate, 38 mg of lithium chloride and 90 mg of zirconium chloride described in step 1).

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