A method for preparing a solid-state battery copolymer

Abstract

The application belongs to the technical field of polymer electrolyte membranes, and relates to a preparation method of a solid-state battery copolymer. The application optimizes a solid-state battery by using a polymer material, and improves good physical and chemical properties and electrochemical properties of the battery. With the characteristics of high chemical stability and electrochemical stability of the polymer material, the application is one of methods for solving the safety problem of the current lithium ion battery.

Description

Technical Field

[0001] This invention belongs to the field of polymer electrolyte membrane technology, and particularly relates to a method for preparing a solid-state battery copolymer. Background Technology

[0002] In 2020, global sales of new energy vehicles exceeded 3.86 million units, of which my country sold 1.552 million units, with an annual growth rate of over 10%. In terms of overall sales, demand from China and Europe was the most significant, accounting for more than 80% of total sales. Currently, global automakers are competing for penetration and market share in various markets. In 2020, Europe's sales and growth rate of new energy vehicles both exceeded those of China. The electrification technology roadmap is already clear, and Europe will surpass China to become the largest market for new energy vehicles in the future.

[0003] The batteries used in current new energy vehicles are all liquid lithium batteries, whose main problems are low energy density and poor safety. The biggest difference between solid-state batteries and traditional electrolyte lithium batteries is that traditional lithium batteries use an electrolyte separator and liquid substances in the middle, while solid-state batteries use solid electrolytes. The liquid electrolyte in solid-state batteries has the following advantages: (1) high safety, which greatly reduces the risk of battery runaway; (2) solid-state electrochemical batteries can improve the theoretical energy density, which is expected to solve the range problem of new energy vehicles; (3) simplified model, which further reduces the weight of the battery in a limited space.

[0004] Currently, there are three main electrolyte systems for solid-state batteries: polymer, sulfide, and oxide. European solid-state batteries primarily use polymer systems, while the US uses a solid-liquid hybrid system. In Asia, Japan and South Korea mainly use oxide systems. Compared to oxide and sulfide solid-state electrolytes, although polymer solid-state electrolytes are somewhat inferior in ionic conductivity, electrochemical window, and lithium-ion transference number, they also have advantages that oxide and sulfide solid-state electrolytes cannot match. Common polymer solid-state electrolytes all have good flexibility, thus exhibiting excellent interfacial contact and good processing performance.

[0005] Based on solving the above problems, this invention uses a self-made solid-state battery copolymer electrolyte and applies the prepared electrolyte to coin cell assembly, so that the copolymer has good liquid absorption rate and electrochemical performance. Summary of the Invention

[0006] Based on solving the above problems, this invention uses a self-made copolymer material to prepare an electrolyte membrane, and uses the prepared electrolyte membrane for battery assembly to provide a novel solid-state battery. The electrolyte membrane has good liquid absorption rate and electrochemical performance.

[0007] This invention is achieved through the following technical solution: a method for preparing a solid-state battery copolymer, characterized by comprising the following steps:

[0008] (1) Ultra-dry N,N-dimethylformamide (DMF) is bubbled in an oxygen-free environment;

[0009] (2) Add azobisisobutyronitrile (AIBN) to the container to maintain an oxygen-free environment;

[0010] (3) Transfer the bubbled DMF to the container of step (2), then add styrene and methyl methacrylate (MMA), bubble with N2, and then transfer the reaction.

[0011] (4) After the reaction is complete, cool to room temperature, pour into deionized water, and a white solid will precipitate. Filter by suction.

[0012] (5) Dissolve the filter cake in DMF, add deionized water, filter, and freeze dry to obtain white copolymer P (MMA-Sty) solid.

[0013] Preferably, the preparation method includes the following steps:

[0014] (1) Replace the N2 in the single-necked bottle three times, add 5-20 mL of ultra-dry N,N-dimethylformamide (DMF), bubble for 20-40 min, and maintain an oxygen-free environment;

[0015] (2) Add 0.03-0.15 g of azobisisobutyronitrile (AIBN) to the Shrek bottle, and replace the N2 three times to maintain an oxygen-free environment;

[0016] (3) Transfer the bubbled DMF to a Shrek bottle, then add 0.2-1.0 mL of styrene and 2.0-9.0 mL of methyl methacrylate (MMA), bubble with N2 for 20-40 min, and then transfer to 60-80℃ for reaction for 4-8 h;

[0017] (4) After the reaction is complete, cool to room temperature and pour into 10-60 mL of deionized water. A white solid will precipitate. Filter the solid.

[0018] (5) Dissolve the filter cake in 3-15 mL of DMF, add deionized water, filter, and freeze dry to obtain white copolymer P (MMA-Sty) solid.

[0019] More preferably, the N2 bubbling rate in steps (1) and (3) is 2-3 bubbles / s.

[0020] More preferably, the pouring into deionized water in step (4) requires continuous stirring.

[0021] More preferably, the single-necked bottle has a capacity of 25 mL, and the Shrek bottle has a capacity of 50 mL.

[0022] The present invention also provides a method for preparing a copolymer film for a solid-state battery. In step (5), DMF and deionized water are added to the P (MMA-Sty) and PVDF obtained, and the mixture is heated and stirred to obtain a white solution. The obtained white solution is cast onto a glass plate and then slowly placed in a water bath in deionized water to solidify. After it is completely transformed into a white film, it is taken out. The obtained white film is placed on a glass heating plate to dry the surface moisture and then vacuum dried to obtain the copolymer film for a solid-state battery.

[0023] Preferably, 0.1-1.0 g P (MMA-Sty) and 0.1-0.7 g PVDF are weighed into a round-bottom flask, and then 5-30 mL DMF and 100-1000 mL deionized water are added dropwise. The flask is then placed on a stirring table and heated and stirred in an oil bath at 50-80°C for 2-4 hours to obtain a white solution. The obtained white solution is cast onto a glass plate and then slowly placed in a water bath at 60-90°C to solidify. After it has completely turned into a white film, it is removed. The obtained white film is placed on a glass heating plate and dried at 50-80°C to remove surface moisture. Then it is placed in a vacuum drying oven at 60-80°C for 6-18 hours to obtain the copolymer film for solid-state batteries.

[0024] More preferably, the stirring rate is 500-2000 r / min.

[0025] More preferably, the glass plate is made of plexiglass.

[0026] More preferably, the vacuum degree of the vacuum drying oven is 0.1 MPa.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention optimizes solid-state batteries using polymeric materials, improving their physicochemical and electrochemical properties. Utilizing the high chemical and electrochemical stability of polymeric materials is one method to address the safety issues currently present in lithium-ion batteries. Detailed Implementation

[0029] The present invention is illustrated below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0030] Example 1

[0031] The single-necked flask was purged with N2 three times, and 10 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 30 min to maintain an oxygen-free environment. 0.075 g of azobisisobutyronitrile (AIBN) was added to the Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to the Shrek flask, followed by the addition of 0.5 mL of styrene (Sty) and 4.5 mL of methyl methacrylate (MMA). After bubbling with N2 for 30 min, the mixture was transferred to 80 °C and reacted for 6 h.

[0032] After the reaction was completed and cooled to room temperature, the solid was poured into 30 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 6 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.3 g of P(MMA-Sty) and 0.2 g of PVDF were weighed into a round-bottom flask, and then 10 mL of DMF and 300 mL of deionized water were added dropwise. The flask was then heated and stirred in a 60°C oil bath for 3 hours to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80°C deionized water bath to solidify. Once the solidified film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 60°C, and then dried in a vacuum drying oven at 80°C for 12 hours to obtain a copolymer membrane for a solid-state battery. The membrane exhibited a liquid absorption rate of 112.6%, a porosity of 52.1%, and a room-temperature ionic conductivity of 5.2 mS / cm.

[0033] Example 2

[0034] The single-necked flask was purged with N2 three times, and 5 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 20 min to maintain an oxygen-free environment. 0.03 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 0.2 mL of styrene (Sty) and 2.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 30 min, the mixture was transferred to 80 °C and reacted for 6 h.

[0035] After the reaction was completed and cooled to room temperature, the solid was poured into 10 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 3 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.1 g of P(MMA-Sty) and 0.1 g of PVDF were weighed into a round-bottom flask, and 5 mL of DMF and 100 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 60 °C for 3 h to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80 °C deionized water bath to solidify. Once the film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 80 °C to remove surface moisture, and then dried in a vacuum drying oven at 80 °C for 16 h to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 111.2%, a porosity of 51.8%, and a room temperature ionic conductivity of 5.1 mS / cm.

[0036] Example 3

[0037] The single-necked flask was purged with N2 three times, and 20 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 40 min, maintaining an oxygen-free environment. 0.15 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 1.0 mL of styrene (Sty) and 9.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 30 min, the mixture was transferred to a container and reacted at 60 °C for 8 h.

[0038] After the reaction was completed and cooled to room temperature, the solid was poured into 60 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 15 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 1.0 g of P(MMA-Sty) and 0.7 g of PVDF were weighed into a round-bottom flask, and 30 mL of DMF and 1000 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 80 °C for 4 h to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in a water bath at 75 °C to solidify. Once the film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 60 °C to remove surface moisture, and then dried in a vacuum drying oven at 60 °C for 18 h to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 108.6%, a porosity of 48.6%, and a room temperature ionic conductivity of 4.8 mS / cm.

[0039] Example 4

[0040] The single-necked flask was purged with N2 three times, and 8 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 25 min, maintaining an oxygen-free environment. 0.06 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 0.4 mL of styrene (Sty) and 3.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 25 min, the mixture was transferred to a container and reacted at 65°C for 5 h.

[0041] After the reaction was completed and cooled to room temperature, the solid was poured into 20 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 5 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.2 g of P(MMA-Sty) and 0.15 g of PVDF were weighed into a round-bottom flask, and 8 mL of DMF and 200 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 65°C for 2.5 h to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in a water bath at 65°C to solidify. Once the solidified film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 65°C to remove surface moisture, and then dried in a vacuum drying oven at 65°C for 10 h to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 109.1%, a porosity of 49.3%, and a room temperature ionic conductivity of 4.9 mS / cm.

[0042] Example 5

[0043] The single-necked flask was purged with N2 three times, and 15 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 30 min, maintaining an oxygen-free environment. 0.12 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 0.8 mL of styrene (Sty) and 8.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 40 min, the mixture was transferred to a container and reacted at 75°C for 8 h.

[0044] After the reaction was completed and cooled to room temperature, the solid was poured into 50 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 12 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.8 g of P(MMA-Sty) and 0.6 g of PVDF were weighed into a round-bottom flask, and 25 mL of DMF and 800 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 75°C for 3 hours to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in a water bath at 75°C to solidify. Once the film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 75°C to remove surface moisture, and then dried in a vacuum drying oven at 75°C for 16 hours to obtain a copolymer membrane for a solid-state battery. The membrane exhibited a liquid absorption rate of 103.3%, a porosity of 46.5%, and a room-temperature ionic conductivity of 4.6 mS / cm.

[0045] Example 6

[0046] The single-necked flask was purged with N2 three times, and 20 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 40 min, maintaining an oxygen-free environment. 0.075 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 0.2 mL of styrene (Sty) and 2.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 40 min, the mixture was transferred to 80 °C and reacted for 4 h.

[0047] After the reaction was completed and cooled to room temperature, the solid was poured into 60 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 15 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.1 g of P(MMA-Sty) and 0.7 g of PVDF were weighed into a round-bottom flask, and 30 mL of DMF and 1000 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 80 °C for 4 h to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80 °C deionized water bath to solidify. Once the solidified film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 80 °C to remove surface moisture, and then dried in a vacuum drying oven at 80 °C for 8 h to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 102.3%, a porosity of 42.5%, and a room temperature ionic conductivity of 3.8 mS / cm.

[0048] Example 7

[0049] The single-necked flask was purged with N2 three times, and 5 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 20 min, maintaining an oxygen-free environment. 0.15 g of azobisisobutyronitrile (AIBN) was added to a Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to a Shrek flask, followed by the addition of 1.0 mL of styrene (Sty) and 9.0 mL of methyl methacrylate (MMA). After bubbling with N2 for 40 min, the mixture was transferred to a container and reacted at 60 °C for 8 h.

[0050] After the reaction was completed and cooled to room temperature, the solid was poured into 60 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 3 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 1.0 g of P(MMA-Sty) and 0.7 g of PVDF were weighed into a round-bottom flask, and 5 mL of DMF and 100 mL of deionized water were added dropwise. The flask was then heated and stirred in an oil bath at 80 °C for 2 h to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80 °C deionized water bath to solidify. Once the film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 80 °C to remove surface moisture, and then dried in a vacuum drying oven at 60 °C for 18 h to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 100.8%, a porosity of 40.2%, and a room temperature ionic conductivity of 2.9 mS / cm.

[0051] Comparative Example 1

[0052] The single-necked flask was purged with N2 three times, and 10 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 30 min to maintain an oxygen-free environment. 0.075 g of azobisisobutyronitrile (AIBN) was added to the Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to the Shrek flask, followed by the addition of 0.5 mL of styrene (Sty) and 4.5 mL of methyl methacrylate (MMA). After bubbling with N2 for 30 min, the mixture was transferred to 80 °C and reacted for 6 h.

[0053] After the reaction was completed and cooled to room temperature, the solid was poured into 30 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 6 mL of DMF, and deionized water was added, followed by filtration. 0.3 g of P(MMA-Sty) and 0.2 g of PVDF were weighed into a round-bottom flask, and then 10 mL of DMF and 300 mL of deionized water were added dropwise. The flask was then heated and stirred in a 60°C oil bath for 3 hours to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80°C deionized water bath to solidify. Once the solidified film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 60°C, and then dried in a vacuum drying oven at 80°C for 12 hours to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 88.2%, a porosity of 26.5%, and a room temperature ionic conductivity of 1.3 mS / cm.

[0054] Comparative Example 2

[0055] The single-necked flask was purged with N2 three times, and 10 mL of ultra-dry N,N-dimethylformamide (DMF) was added. The mixture was bubbled for 30 min to maintain an oxygen-free environment. 0.075 g of azobisisobutyronitrile (AIBN) was added to the Shrek flask, and the N2 was purged three times, again maintaining an oxygen-free environment. The bubbled DMF was transferred to the Shrek flask, followed by the addition of 0.5 mL of styrene (Sty) and 4.5 mL of methyl methacrylate (MMA). After bubbling with N2 for 30 min, the mixture was transferred to 80 °C and reacted for 6 h.

[0056] After the reaction was completed and cooled to room temperature, the solid was poured into 30 mL of deionized water, precipitating a white solid. The solid was then filtered. The filter cake was dissolved in 6 mL of DMF, deionized water was added, and the mixture was filtered again and freeze-dried to obtain a white copolymer P(MMA-Sty) solid. 0.3 g of P(MMA-Sty) was weighed, and 10 mL of DMF and 300 mL of deionized water were added dropwise. The mixture was then heated and stirred in a 60°C oil bath for 3 hours to obtain a white solution. The solution was cast onto a glass plate and then slowly placed in an 80°C deionized water bath to solidify. Once the film had completely transformed into a white membrane, it was removed. The resulting white membrane was dried on a glass heating plate at 60°C to remove surface moisture, and then dried in a vacuum drying oven at 80°C for 12 hours to obtain a copolymer membrane for a solid-state battery. The polymer membrane was tested and found to have a liquid absorption rate of 62.2%, a porosity of 5.6%, and a room temperature ionic conductivity of 0.38 mS / cm.

Claims

1. A method for preparing a solid-state battery copolymer, characterized in that... Includes the following steps: (1) Replace the N2 in the single-necked bottle three times, add 5-20 mL of ultra-dry N,N-dimethylformamide (DMF), bubble for 20-40 min, and maintain an oxygen-free environment; (2) Add 0.03-0.15 g of azobisisobutyronitrile (AIBN) to the Shrek bottle, and replace the N2 three times to maintain an oxygen-free environment; (3) Transfer the bubbled DMF to a Shrek bottle, then add 0.2-1.0 mL of styrene and 2.0-9.0 mL of methyl methacrylate (MMA), bubble with N2 for 20-40 min, and then transfer to 60-80℃ for reaction for 4-8 h; (4) After the reaction is complete, cool to room temperature and pour into 10-60 mL of deionized water. A white solid will precipitate. Filter the solid. (5) Dissolve the filter cake in 3-15 mL of DMF, add deionized water, filter, and freeze dry to obtain a white copolymer P (MMA-Sty) solid; weigh 0.1-1.0 g of P (MMA-Sty) and 0.1-0.7 g of PVDF into a round-bottom flask, add 5-30 mL of DMF and 100-1000 mL of deionized water, place on a stirring table and heat and stir in an oil bath at 50-80℃ for 2-4 h to obtain a white solution; cast the obtained white solution onto a glass plate, and then slowly place it in a water bath at 60-90℃ to solidify. After it is completely transformed into a white film, take it out; place the obtained white film on a glass heating plate to dry the surface moisture at 50-80℃, and then place it in a vacuum drying oven at 60-80℃ for 6-18 h to obtain the copolymer film of the solid-state battery.

2. The preparation method according to claim 1, characterized in that... The N2 bubbling rate mentioned in steps (1) and (3) is 2-3 bubbles / s.

3. The preparation method according to claim 1, characterized in that... The process described in step (4) involves continuously stirring the water as it is poured into the deionized water.

4. The preparation method according to claim 1, characterized in that... The stirring rate is 500-2000 r / min.

5. The preparation method according to claim 1, characterized in that... The glass plate is made of plexiglass.

6. The preparation method according to claim 1, characterized in that... The vacuum degree of the vacuum drying oven is 0.1 MPa.

7. The preparation method according to claim 1, characterized in that... The single-necked bottle has a capacity of 25 mL, and the Shrek bottle has a capacity of 50 mL.