Preparation method and application of PAM / saccharide hydrogel composite material
The synthesis of PAM/saccharide hydrogel composites by one-step method of radical polymerization solves the leakage and stability problems of traditional liquid electrolytes in zinc ion batteries and hybrid capacitors, and achieves higher electrochemical and mechanical properties.
Patent Information
- Application Number
- CN202510531004.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-05-30
AI Technical Summary
Traditional liquid electrolytes are prone to leakage in zinc ion batteries and hybrid capacitors, and the uncontrolled growth and side reactions of zinc dendrites lead to low Coulomb efficiency and zinc loss, affecting device stability and safety.
The PAM/saccharide hydrogel composite was synthesized by a one-step method of radical polymerization. Through the interaction of sugars with PAM and zinc salt, a material with excellent mechanical strength and interfacial chemical properties was formed, and the electrolytes were used for zinc storage devices.
It improves the electrochemical performance of zinc storage devices, enhances mechanical properties and ionic conductivity, reduces zinc losses and interface degradation, and improves the stability and safety of the device.
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Figure CN120059045A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of electrochemical energy storage materials, and particularly relates to a method for synthesizing a hydrogel electrolyte by a one-step free radical polymerization method and its application in zinc storage. Background Art
[0002] Developing clean and safe energy is an inevitable trend for future sustainable development. In the case where lithium-ion batteries (LIBs) and lead-acid batteries (LABs) dominate the main energy storage market, the safety of lithium-ion batteries and the environmental pollution problems of lead-acid batteries are worrying. Flow batteries have good cycle stability, but their usage scenarios are greatly limited. Compared with these batteries, aqueous zinc-ion batteries (ZIBs) and zinc-ion hybrid capacitors (ZHCs) have received extensive attention due to their low cost, high safety, and environmental friendliness. However, traditional liquid electrolytes have strong fluidity, are prone to leakage problems, and during the cycling process, uncontrolled growth of zinc dendrites and a series of side reactions occur at the electrode / electrolyte interface, resulting in low coulombic efficiency (CE) and irreversible zinc loss in aqueous electrolytes, thus leading to device failure. In addition, the stability and safety of flexible ZIBs and ZHCs under complex application conditions are crucial for their practical applications in flexible electronics. Therefore, there is an urgent need to explore effective strategies to regulate interfacial chemistry to protect flexible ZIBs and ZHCs from the above processes.
[0003] To solve the above problems, various strategies for optimizing gel electrolytes have been proposed. Among them, functional hydrogel electrolytes show great promise in flexible zinc storage devices because they can not only provide ion transfer channels and effectively regulate the deposition / stripping behavior of zinc, but also prevent leakage of liquid electrolytes to ensure safety. Currently, the most studied hydrogel electrolytes for flexible zinc storage devices are usually based on polyvinyl alcohol (PVA), polyacrylic acid (PAA), and polyacrylamide (PAM) matrices. Especially for PAM-based hydrogel electrolytes, because their synthesis process is simple, and they have good compatibility and mechanical properties. More importantly, the negatively charged amide groups in the PAM chain can block active H 2 O molecules and coordinate with Zn 2+ to improve its distribution and effectively regulate the zinc deposition behavior. However, covalently crosslinked PAM hydrogels may deform and damage under harsh environments and are not easily reformed. In addition, the weak physical contact between the PAM hydrogel electrolyte and the electrode usually leads to interfacial slippage during the bending process. Specifically, in actual situations, repeated bending will further exacerbate interfacial degradation and result in uneven zinc deposition in the bent and flat regions. Therefore, there is an urgent need to modify the PAM hydrogel to improve its mechanical properties and ionic conductivity, thereby improving the electrochemical performance of zinc storage devices assembled with PAM-based hydrogels as electrolytes. Summary of the Invention
[0004] The object of the present invention is to provide a preparation method of a PAM / saccharide hydrogel composite material with excellent mechanical strength and interfacial chemical properties and its application in zinc storage devices. The PAM / saccharide hydrogel composite material obtained by the preparation method provided by the present invention is simple to synthesize and can withstand different pressure environmental conditions. In the present invention, a strong interaction can be formed between the -OH groups in the saccharide molecules and the polar groups in the PAM molecules. The saccharide can be used as a powerful network repair agent for PAM-based hydrogels to improve the mechanical properties of the hydrogel. In addition, the saccharide can even replace the hydrated H 2+ O molecules by forming stronger hydrogen bonds with Zn 2 , which is beneficial to the uniform deposition of Zn 2+ , and further improves the electrochemical performance of the zinc storage device assembled with the PAM / saccharide hydrogel composite material as the electrolyte.
[0005] The PAM / saccharide hydrogel composite material prepared by the present invention has the following characteristics. It is composed of saccharide, PAM and zinc salt, has a flexible and interconnected porous structure, the tensile stress is between 10 and 40 kPa, and the compressive stress is between 400 and 800 kPa.
[0006] In order to achieve the above object of the invention, the present invention provides the following technical solutions: The present invention provides a preparation method of a PAM / saccharide hydrogel composite material, comprising the following steps: (1) Uniformly disperse saccharide, acrylamide and zinc salt in deionized water; (stir, magnetic stirrer) (2) Add a crosslinking agent and an initiator to the dispersion liquid in step (1), stir evenly, and obtain a PAM / saccharide hydrogel composite material through thermal initiation polymerization reaction.
[0007] Preferably, the saccharide includes glucose, galactose, L-sorbose, mannose, trehalose, xylitol, fructose, maltose, lactose, starch.
[0008] Preferably, the zinc salt in step (1) includes ZnSO 4 , ZnCl 2 , Zn(ClO 4 ) 2 , Zn(CH 3 COO) 2 , Zn(BF 4 ) 2 and Zn(CF 3 SO 3 ) 2 ; the crosslinking agent in step (2) includesN,N Dimethyl bisacrylamide, diethylene glycol divinyl ether and 1,3-propanediol diacrylate; the initiators in step (2) include ammonium persulfate, azoisobutyronitrile and 4-cyanopentanoic acid.
[0009] Preferably, the concentration of acrylamide in step (1) is 0.05 - 1 g / mL.
[0010] Preferably, the concentration of saccharides in step (1) is 0.05 - 0.5 g / mL, and the concentration of zinc salt is 0.5 - 2 mol / L.
[0011] Preferably, the addition amount of the initiator in step (2) is 1 - 5% of the mass of acrylamide, and the addition amount of the crosslinking agent is 0.1 - 0.5% of the mass of acrylamide.
[0012] Preferably, the temperature of the thermal initiation polymerization reaction in step (2) is 40 °C - 70 °C, and the polymerization time is 0.5 h - 2 h.
[0013] The present invention also provides a PAM / saccharide hydrogel composite material prepared by the preparation method described in the above technical solution and its applications in zinc ion hybrid capacitors and electrolyte materials for zinc ion batteries. Description of the Drawings
[0014] Figure 1 SEM (scanning electron microscope) image of the sample prepared in Example 1; Figure 2 Ionic conductivity diagram of the sample prepared in Example 1; Figure 3 Mechanical tensile curve of the sample prepared in Example 1; Figure 4 Mechanical compression curve of the sample prepared in Example 1; Figure 5 Electrochemical rate performance curve of the quasi-solid-state zinc-iodine battery composed of the sample prepared in Example 1; Figure 6 Electrochemical cycling performance curve of the quasi-solid-state zinc-iodine battery composed of the sample prepared in Example 1.
[0015] Figure 7 Ionic conductivity diagram of the sample prepared in Comparative Example 1; Figure 8 Mechanical tensile curve of the sample prepared in Comparative Example 1; Figure 9 Mechanical compression curve of the sample prepared in Comparative Example 1. Detailed Description of the Invention
[0016] The present invention provides a preparation method of a PAM / saccharide hydrogel composite material, comprising the following steps: (1) Uniformly disperse saccharides, acrylamide, and zinc salt in deionized water; (2) Add a crosslinking agent and an initiator to the dispersion in step (1), stir evenly, and obtain a PAM / saccharide hydrogel composite material through thermal-initiated polymerization reaction.
[0017] In the present invention, the concentration of acrylamide is preferably 0.05 - 1 g / mL, more preferably 0.1 - 0.3 g / mL. If the concentration of acrylamide is too low, the degree of crosslinking will be too low and it is not easy to form a gel. If the concentration of acrylamide is too high, the solution will be too thick and premature polymerization is likely to occur, resulting in uneven polymerization.
[0018] In the present invention, the concentration of saccharides is 0.05 - 0.5 g / mL, more preferably 0.2 - 0.3 g / mL. If the concentration of saccharides is too low, the improvement effect of ionic conductivity will be poor. If the concentration of saccharides is too high, the ionic conductivity will decrease.
[0019] In the present invention, the addition amount of the initiator is 1 - 5% of the mass of acrylamide, more preferably 2.5 - 3.5% of the mass of acrylamide. When the addition amount of the initiator is too small, the reaction cannot occur. When it is too much, over-initiation will occur, making the gel lose its flexibility. The addition amount of the crosslinking agent is 0.1 - 0.5% of the mass of acrylamide, more preferably 0.2 - 0.4% of the mass of acrylamide. When the addition amount of the crosslinking agent is too low, crosslinking is insufficient. When it is too high, over-crosslinking will occur and the hydrogel material will become hard.
[0020] In the present invention, the temperature of the thermal-initiated polymerization reaction is 40 °C - 70 °C, more preferably 55 °C - 65 °C. If the temperature is too low, the polymerization reaction cannot occur smoothly. If the temperature is too high, the gel will denature. The polymerization time is 0.5 h - 2 h, more preferably 1 h - 2 h. If the polymerization time is too short, the polymerization reaction will be insufficient. If the polymerization time is too long, over-initiation will occur and the gel will denature.
[0021] The present invention also provides the application of the PAM / saccharide hydrogel composite material described in the above technical solution as a gel electrolyte in zinc storage devices.
[0022] Next, the technical solutions in the present invention will be clearly and completely described in combination with the examples in the present invention. Obviously, the described examples are only a part of the examples of the present invention, rather than all the examples. Based on the examples in the present invention, all other examples obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention. Examples
[0023] At room temperature, 2 g of acrylamide was weighed and dispersed in 10 mL of deionized water at 60 °C and stirred evenly. 1.8 g of L-sorbose and 2.88 g of ZnSO 4 were added. After stirring evenly, 0.006 g of N,N -dimethylbisacrylamide and 0.06 g of ammonium persulfate were added. After a homogeneous solution was formed, a thermal-initiated polymerization reaction was carried out under the condition of constant temperature at 60 °C to obtain a PAM / L-sorbose polymer hydrogel electrolyte.
[0024] The morphology of the hydrogel was characterized by SEM, and the results are as Figure 1 shown. It can be seen from Figure 1 that the hydrogel material has a rich pore structure. The ionic conductivity was tested using a Chenhua electrochemical workstation 660E, as Figure 2 shown. It can be seen that the ionic conductivity of the hydrogel is 4.0 S m -1 . The tensile and compression properties were tested using a universal tensile tester. The results show that the tensile stress of the hydrogel is 28.7 kPa and the compression stress is 510.8 kPa ( Figure 3 and Figure 4 ).
[0025] Application Example 1 A zinc-ion battery was assembled with iodine tablets as the positive electrode, Zn foil as the negative electrode, and the hydrogel electrolyte prepared in Example 1 as the separator and electrolyte, and assembled into a pouch soft-pack battery. The rate performance and cycle performance of the zinc-ion battery prepared in Application Example 1 were tested. The test conditions were: constant current charge and discharge mode, cycling 15 times at current densities of 0.2, 0.5, 1, 2, and 5 A g -1 respectively, and finally returning to 0.2 A g -1 . The discharge cut-off voltage was 0.6 V and the charge cut-off voltage was 1.6 V. The results are as Figure 5 and Figure 6 shown. It can be seen from Figure 5 that the specific capacities of the zinc-ion battery prepared in Application Example 1 at 0.2, 0.5, 1, 2, and 5 A g -1 are 373.1, 360.3, 351.3, 337.9, and 314.2 mAh g -1 respectively, and the specific capacity when finally restored to 0.2 A g -1 is 367.2 mAh g -1 , indicating that it has good rate performance and electrochemical reversibility. It can be seen from Figure 6 that under the condition of 10 A g -1 , it can be stably cycled 11,000 times and has a capacity retention rate of 73.9%.
[0026] Comparative Example 1 At room temperature, 2 g of acrylamide was weighed and dispersed in 10 mL of deionized water at 60 °C and stirred evenly. 2.88 g of ZnSO 4 , after stirring evenly, 0.006 g of N,N -dimethylbisacrylamide and 0.06 g of ammonium persulfate were added. After it formed a uniform solution, a thermal initiation polymerization reaction was carried out under the condition of constant temperature at 60 °C to obtain a PAM polymer hydrogel electrolyte. The ionic conductivity of it was tested by a Chenhua electrochemical workstation 660E, as Figure 7 shown. It can be seen that the ionic conductivity of the hydrogel was 3.3 S m -1 . The tensile and compression properties of it were tested by a universal tensile tester. The results showed that the tensile stress of the hydrogel was 19.3 kPa and the compression stress was 89.4 kPa ( Figure 8 and Figure 9 ). Example
[0027] At room temperature, 2 g of acrylamide was weighed and dispersed in 5 mL of deionized water at 60 °C and stirred evenly. 1.8 g of glucose and 2.88 g of ZnSO 4 were added. After stirring evenly, 0.006 g of N,N -dimethylbisacrylamide and 0.06 g of ammonium persulfate were added. After it formed a uniform solution, a thermal initiation polymerization reaction was carried out under the condition of constant temperature at 60 °C to obtain a PAM / glucose polymer hydrogel electrolyte. Example
[0028] At room temperature, 2 g of acrylamide was weighed and dispersed in 10 mL of deionized water at 60 °C and stirred evenly. 0.9 g of xylitol and 2.88 g of ZnSO 4 were added. After stirring evenly, 0.006 g of diethylene glycol divinyl ether and 0.06 g of ammonium persulfate were added. After it formed a uniform solution, a thermal initiation polymerization reaction was carried out under the condition of constant temperature at 60 °C to obtain a PAM / xylitol polymer hydrogel electrolyte. Example
[0029] At room temperature, 2 g of acrylamide was weighed and dispersed in 10 mL of deionized water at 60 °C and stirred evenly. 0.36 g of fructose and 2.88 g of ZnSO 4 were added. After stirring evenly, 0.006 g of N,N -dimethylbisacrylamide and 0.06 g of azobisisobutyronitrile were added. After it formed a uniform solution, a thermal initiation polymerization reaction was carried out under the condition of constant temperature at 60 °C to obtain a PAM / fructose polymer hydrogel electrolyte.
[0030] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A PAM / saccharide hydrogel composite material, characterized in that: The material is composed of sugars, PAM and zinc salts, has a flexible, interconnected porous structure, a tensile stress between 10 and 40 kPa, and a compressive stress between 400 and 800 kPa.
2. A method for preparing a PAM / saccharide hydrogel composite material, comprising the following steps: (1) Dispersing sugar, acrylamide and zinc salt uniformly in deionized water; (2) Add a crosslinking agent and an initiator to the dispersion in step (1), stir evenly, and initiate a polymerization reaction by heat initiation at a polymerization temperature of 40°C to 70°C for a polymerization time of 0.5 h to 2 h to obtain a PAM / saccharide hydrogel composite material.
3. The method for preparing the PAM / saccharide hydrogel composite material according to claim 2, characterized in that: The sugars include monosaccharides and polysaccharides such as glucose, fructose, galactose, L-sorbose, mannose and xylitol.
4. The method for preparing the PAM / saccharide hydrogel composite material according to claim 2, characterized in that: The zinc salts include ZnSO4, ZnCl2, Zn(ClO4)2, Zn(CH3COO)2, Zn(BF4)2 and Zn(CF3SO3)2; the crosslinking agent includes N,N Dimethylbisacrylamide, diethylene glycol divinyl ether and 1,3-propylene glycol diacrylate; the initiator includes ammonium persulfate, azoisobutyronitrile and 4-cyanovaleric acid.
5. The method for preparing a PAM / saccharide hydrogel composite material according to claim 2, characterized in that: The concentration of acrylamide is 0.05~1 g / mL.
6. The method for preparing the PAM / saccharide hydrogel composite material according to claim 2, characterized in that: The concentration of sugars is 0.05~0.5 g / mL, and the concentration of zinc salts is 0.5~2 mol / L.
7. The method for preparing the PAM / saccharide hydrogel composite material according to claim 2, characterized in that: The added amount of the initiator is 1-5% of the mass of acrylamide, and the added amount of the cross-linking agent is 0.1-0.5% of the mass of acrylamide.
8. The PAM / saccharide hydrogel composite material prepared by the method according to any one of claims 2 to 7.
9. Use of the PAM / saccharide hydrogel composite material according to claim 1 or the PAM / saccharide hydrogel composite material prepared by the preparation method according to claim 8 as an electrolyte material for zinc ion hybrid capacitors and zinc ion batteries.