Biomass-based flexible hydrogel electrolyte adapting to extreme environment as well as preparation method and application of biomass-based flexible hydrogel electrolyte
By using hydrogel electrolytes prepared by biomass materials such as gelatin and sodium lignin sulfonate, combined with the addition of high concentration lithium salts, high performance and self-healing ability in extreme environments are achieved, and the existing hydrogel electrolytes are solved.
Patent Information
- Application Number
- CN202411954824.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-05-13
AI Technical Summary
Existing hydrogel electrolytes have deteriorated performance in extreme environments, and most designs do not comply with green chemistry principles, which have high cost and toxic residues.
The biomass-based flexible hydrogel electrolyte prepared with gelatin, lithium salt, LiOH·H2O, sodium lignin sulfonate and polyethylene glycol diglycidyl ether is achieved through covalent crosslinking and the addition of high-concentration lithium salts.
The hydrogel electrolyte exhibits high energy density, stable electrochemical performance and self-regeneration ability in extreme environments, solving the problem of performance degradation of traditional hydrogel electrolytes in extreme environments, and complies with the principle of green chemistry, is cheap and harmless.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of flexible electronic materials, and more specifically, to a biomass-based flexible hydrogel electrolyte adaptable to extreme environments and a preparation method and application thereof. Background Art
[0002] Flexible electronic materials are rapidly changing human lifestyles and social development. Among them, wearable devices, including stretchable sensors, flexible displays, and implantable physiological signal monitors, require built-in power sources that match their mechanical flexibility. Traditional batteries or supercapacitors contain liquid electrolytes, which involve complex packaging processes during preparation, have poor mechanical properties, and are at risk of electrolyte leakage. The development of hydrogel electrolytes (HE) can effectively solve these problems, enabling soft electronic devices to be used in interdisciplinary fields. In the common use scenarios of flexible energy storage devices, inevitable deformations such as stretching, bending, folding, and even puncture and tearing usually occur. The hydrogel electrolyte may slip and crack relative to the electrode, resulting in a decrease in device performance. Therefore, it is necessary to construct a soft and dynamically cross-linked hydrogel network with stable interfacial adhesion and rapid self-healing ability to ensure the durability of the device.
[0003] In order to regulate the mechanical properties of hydrogels, various strategies have been developed, including constructing energy dissipation structures (such as double cross-linked or double network structures), biomimetic design, and Hofmeister effect. Liu et al. used activated modified lignin to prepare a double cross-linked hydrogel with multiple covalent and non-covalent cross-links, achieving up to 700% elongation at break and excellent fatigue resistance (Liu, Y. et al. Preparation of dual cross-linked hydrogel electrolytes containing modified lignin for supercapacitors and sensors. Chem. Eng. J. 480, 148259 (2024)). Salts with different Hofmeister sequences change the interaction between the hydrophilic groups on the polymer chain and the water molecules, change the hydrogen bond structure in HE, and thus regulate the mechanical properties of flexible HE. The addition of salts also produces abundant ionic interactions in HE, further increasing the number of hydrogen bonds, enabling HE to self-heal and adhere. High concentrations of salt can improve the migration efficiency of ions in HE, improve the ionic conductivity and electrochemical performance of the device, expand the electrochemical stability window of HE and inhibit the decomposition of water. Wu et al. reversibly changed the mechanical properties of hydrogels by using the strategy of ion-regulated polymer chain aggregation based on the Hofmeister effect and prepared an ultra-tough polyvinyl alcohol hydrogel (150±20 MJ m -3)(Wu, S. et al. Poly (vinyl alcohol) hydrogels with broad-range tunable mechanical properties via the hofmeister effect. Adv. Mater. 33, e2007829 (2021)). Interestingly, due to its rich functional groups such as –OH, –COOH and –NH2, the skin has excellent properties of flexibility, self-repairing, wide temperature range adaptability, water content regulation and ion transport, which has inspired a series of bionic material designs based on skin function and structure. Based on the bionic design strategy, Chen et al. designed a gelatin-based conductive film with an elastic modulus (20-420 kPa) and Poisson's ratio (0.25-0.52) that are highly consistent with human soft tissue (Chen, Y. et al. Gelatin-based metamaterial hydrogel films with high conformality for ultra-soft tissue monitoring. Nano-Micro. Lett. 16, 34 (2024).).
[0004] Hydrogels are easily dehydrated at high temperatures and freeze in low temperature environments. In order to improve the dehydration tolerance and antifreeze ability of hydrogels in a wider temperature range, researchers have explored methods such as adding ion-specific salts, antifreeze organic solvents, and amphoteric polymers. Qiu et al. studied the connection between the freezing behavior of water and tetrahedral entropy in zinc ion electrolytes by analyzing experimental spectra and molecular simulation results, revealing that the freezing point of aqueous zinc ion liquid electrolytes is directly related to the entropy value of the system (Qiu, M. et al. Tailoring water structure with high-tetrahedral-entropyfor antifreezing electrolytes and energy storage at-80℃. Nat Commun. 14, 601 (2023).). Rong et al. used water / ethylene glycol as a dispersion medium and successfully prepared a hydrogel electrolyte with excellent flexibility and ionic conductivity even at low temperatures (Rong, Q. Lei, W. Huang, J. & Liu M. Low temperature tolerant organohydrogel electrolytes for flexible solid-state supercapacitors. Adv. Energy Mater. 8, 1801967 (2018).). He et al. constructed a drying-resistant hydrogel containing a zwitterionic oligomer network, which has excellent water retention properties in high temperature and low humidity environments.
[0005] However, creating a multifunctional and environmentally adaptable hydrogel remains a challenging task. Most of its design strategies do not conform to the principles of green chemistry. HEs with excellent performance are usually made from petroleum-based chemicals produced in high-carbon emission industries, such as classic polyvinyl alcohol (PVA) and polyacrylamide (PAM), and require complex structural design and tedious steps using organic synthesis or chemical modification. In addition, achieving properties such as high ionic conductivity, antifreeze ability, anti-dehydration ability and wide voltage window requires expensive and usually toxic or volatile chemicals or additives. In addition, most reported hydrogel electrolytes have problems such as electrolyte-electrode interface mismatch, excessive modulus, inability to adapt to extreme environments, high cost and toxic residues.
[0006] Therefore, developing hydrogel electrolytes with multifunctionality and environmental adaptability is crucial to advancing the development of flexible energy storage devices. Summary of the invention
[0007] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a biomass-based flexible hydrogel electrolyte adaptable to extreme environments and a preparation method and application thereof.
[0008] To achieve the above object, the technical solution of the present invention is as follows:
[0009] A biomass-based flexible hydrogel electrolyte adapted to extreme environments, comprising gelatin, lithium salt, LiOH·H2O, sodium lignin sulfonate, and polyethylene glycol diglycidyl ether;
[0010] The lithium salt includes one of lithium bromide and lithium sulfate;
[0011] The concentrations of the components in the hydrogel electrolyte are as follows: the mass percentage of the gelatin is 9.23% to 38.49%; the molar concentration of the lithium salt is 2 mol / L to 16 mol / L; the mass percentage of LiOH·H2O is 0.08% to 0.17%; the mass percentage of the sodium lignin sulfonate is 0% to 2.03%; and the mass percentage of the polyethylene glycol diglycidyl ether is 0.78% to 2.76%.
[0012] Optionally, the lithium salt is lithium bromide.
[0013] The present invention also discloses a method for preparing the above-mentioned biomass-based flexible hydrogel electrolyte adaptable to extreme environments, comprising the following steps:
[0014] (1) gelatin, sodium lignin sulfonate and LiOH·H2O were dissolved in deionized water, and then LiBr was added under ice bath condition and stirred at 800 rpm to obtain a mixture;
[0015] (2) Adding polyethylene glycol diglycidyl ether to the mixture, and performing covalent crosslinking at 58° C. to 62° C. to obtain the hydrogel electrolyte.
[0016] Optionally, in step (1), the dissolution temperature is 58°C to 62°C.
[0017] Optionally, in step (2), the covalent cross-linking time is 5 h to 8 h.
[0018] The present invention also discloses a biomass-based flexible hydrogel electrolyte adapted to extreme environments as described above, or an application of the biomass-based flexible hydrogel electrolyte prepared by the above preparation method in a supercapacitor.
[0019] Optionally, the application includes:
[0020] Activated carbon, acetylene black and polytetrafluoroethylene powder were mixed in a weight ratio of 8:1:1, dissolved in ethanol, and stirred at room temperature for 12 hours to obtain a slurry;
[0021] The slurry is coated on both sides of the hydrogel electrolyte, and carbon cloth electrode layers are sequentially arranged on both sides of the hydrogel electrolyte loaded with the slurry to form a stable interface adhesion, and then a high energy density double-layer supercapacitor with extreme environmental adaptability is obtained through assembly.
[0022] Optionally, the particle size of the activated carbon is ≥100 mesh, the average particle size of the polytetrafluoroethylene is 25 μm, the average particle size of the acetylene black is 35 nm; and the thickness of the carbon cloth electrode layer is 0.33 mm to 0.37 mm.
[0023] Optionally, the elastic modulus of the hydrogel electrolyte is 8.5 kPa; the high elongation at break of the hydrogel electrolyte is 1558%, and the elongation can be recovered to 1030% after breaking and instantaneous self-healing; the ionic conductivity of the hydrogel electrolyte at -50°C is 1.26 mS / cm; the ionic conductivity of the hydrogel electrolyte at 25°C is 26.71 mS / cm.
[0024] Implementing the embodiments of the present invention will have the following beneficial effects:
[0025] Based on the characteristics of skin such as elasticity, self-repair, wide temperature tolerance, moisture regulation and ion transport, the present invention inspires the preparation of bionic skin hydrogel electrolytes with ultra-softness, self-healing and extreme environment adaptability for the preparation of flexible energy storage devices.
[0026] The present invention proposes a hydrogel electrolyte prepared from gelatin, lithium salt, LiOH·H2O, sodium lignin sulfonate and polyethylene glycol diglycidyl ether, which has low cost, low toxicity and self-healing function. Among them, gelatin and lignin sulfonate form the skeleton of the hydrogel electrolyte through covalent cross-linking, which is similar to the collagen fiber scaffold in skin tissue. The ultra-high concentration of LiBr as a lithium salt gives it ultra-low modulus, ultra-high strain capacity and mechanical properties matching the heterogeneous interface. LiBr introduces a large number of ionic interactions into the hydrogel electrolyte, and together with the hydrogen bond interactions in the highly hydrophilic gel skeleton, firmly binds water molecules inside the gel electrolyte polymer network, giving the hydrogel electrolyte skin-like adaptability over a wide temperature range, as well as the ability to self-repair and self-regenerate. These functional properties have overturned the working mode of traditional electrolytes, making them no longer limited to a single usage scenario, and enabling the flexible energy storage materials assembled from them to be widely used in complex scenarios. Supercapacitors assembled using this skin-mimetic hydrogel electrolyte have high energy density and excellent electrochemical properties in large-angle bending, fracture healing, extremely low temperature and high temperature dry environments, solving the key, difficult and hot issues of how to simultaneously give hydrogel electrolytes excellent mechanical flexibility, electrochemical properties and environmental adaptability.
[0027] 1. LiBr can weaken the hydrogen bond interaction between polymer chains in the gel electrolyte network, enhance its hydrophilicity, and introduce a large number of ionic interactions and electrostatic interactions, so that the skin biomimetic hydrogel electrolyte gives the hydrogel electrolyte an elastic modulus as low as 8.5kPa, a break elongation as high as 1558%, and can recover to 1030% elongation after breaking and instant self-healing, and can rely on physical contact to immediately heal two gel electrolytes into one. The highly polarized gelatin skeleton in the hydrogel electrolyte can promote the rapid migration of lithium ions, and the ionic conductivity at 25°C is as high as 26.71mS / cm.
[0028] 2. Due to the presence of ultra-high concentration of lithium bromide in the skin biomimetic hydrogel electrolyte, it introduces extremely rich non-covalent interactions. It can self-heal in the range of -20°C to 60°C, and the ionic conductivity before and after healing remains almost unchanged, and the mechanical properties after healing can also be restored to more than 830%. The rich ionic groups in the skin biomimetic hydrogel electrolyte can undergo multiple synergistic molecular interactions with the functional groups on the surface of various materials, inducing charge rearrangement on the surface of the material, and achieving rapid, stable and reversible adaptive adhesion at different temperatures. Therefore, without the use of any electrode adhesive or surface treatment, the skin biomimetic hydrogel electrolyte can provide a stable electrode-electrolyte interface to prevent sliding or stratification, and withstand the complex external stresses during device manufacturing and operation, providing a simple and effective assembly method for the preparation process of energy storage materials.
[0029] 3. The ultra-high concentration of lithium bromide in the skin biomimetic hydrogel electrolyte can effectively disrupt the original hydrogen bond arrangement between water molecules in the gel network, and a large number of water molecules are + and Br - The captured water becomes bound water, thus significantly reducing the phase transition temperature of the skin biomimetic hydrogel electrolyte at extremely low temperatures. Differential calorimetry (DSC) analysis showed that the skin biomimetic hydrogel electrolyte loaded with 16M LiBr still did not show an obvious phase transition process at -75°C, proving its ultra-low freezing point and excellent antifreeze performance. The ionic conductivity of the skin biomimetic hydrogel electrolyte at -50° is as high as 1.26mS / cm, and the water loss rate is slow under high temperature and dry conditions. It can achieve self-regeneration by capturing moisture in the air in a normal temperature and humidity environment.
[0030] The strongly hydrated lithium bromide and highly hydrophilic gel skeleton in the skin biomimetic hydrogel electrolyte can firmly bind water molecules in the gel electrolyte, thus delaying the loss of water in high temperature and dry environment. In addition, when the skin biomimetic hydrogel electrolyte is severely dehydrated, it can capture water from the air to achieve the self-regeneration process of the gel's volume, mass and ionic conductivity from low to high. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 The optimization of the mechanical properties of the skin biomimetic hydrogel electrolytes of the embodiments of the present invention. (a) Tensile stress-strain curves of LiBr (2M, 4M, 6M, 8M and 16M), (b) gelatin (Gel, 2.5g, 5.5g and 7.5g), (c) polyethylene glycol diglycidyl ether (PEGDE, 0.25g, 0.3g and 0.4g) and (d) sodium lignin sulfonate (LS, 0g, 0.1g, 0.2g and 0.3g).
[0032] Figure 2 Graph showing the effects of different (a) gelatin content (Gel, 2.5 g, 5.5 g and 7.5 g) and (b) sodium lignin sulfonate content (LS, 0 g, 0.1 g, 0.2 g and 0.3 g) concentrations on the ionic conductivity of the skin biomimetic hydrogel electrolyte according to the embodiments of the present invention.
[0033] Figure 3 Graph showing the effect of different LiBr contents (2M, 4M, 6M, 8M and 16M) on the ionic conductivity of the skin biomimetic hydrogel electrolyte according to the embodiments of the present invention.
[0034] Figure 4 Graphs showing changes in (a) ionic conductivity and (b) mechanical properties of the skin biomimetic hydrogel electrolyte before and after healing at different temperatures in an embodiment of the present invention.
[0035] Figure 5 90° peeling test of the skin biomimetic hydrogel electrolyte of the embodiment of the present invention. (a) Adhesion of the skin biomimetic hydrogel electrolyte to different materials. (b) Adhesion performance of the skin biomimetic hydrogel electrolyte to the carbon cloth electrode at different temperatures.
[0036] Figure 6 The DSC curves of the skin biomimetic hydrogel electrolytes with different LiBr concentrations (2M, 4M, 6M, 8M and 16M) according to the embodiments of the present invention and the phase transition temperatures at extremely low temperatures.
[0037] Figure 7 The anti-dehydration and self-regeneration performance of the skin biomimetic hydrogel electrolyte of the embodiment of the present invention. (a) DSC curves of skin biomimetic hydrogel electrolytes with different lithium bromide concentrations (0M, 2M and 16M); (b) The self-regeneration process of the skin biomimetic hydrogel electrolyte at 25℃ after dehydration at 60℃.
[0038] Figure 8 (a) CV curve, (b) GCD curve and (c) EIS curve of the supercapacitor assembled with skin biomimetic hydrogel electrolyte according to an embodiment of the present invention under bending conditions of 0°, 90° and 180°.
[0039] Fig. 9 The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte according to the embodiment of the present invention at 25°C. (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0040] Fig.10 The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte according to the embodiment of the present invention at -20°C. (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0041] Fig.11 The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte according to the embodiment of the present invention at 60°C. (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0042] Fig.12 The EIS curves of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte according to the embodiment of the present invention before and after cutting and healing at 25°C, -20°C and 60°C.
[0043] Fig.13 The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte according to the embodiment of the present invention at an extremely low temperature of -50°C. (a) CV curve; (b) GCD curve; (c) EIS curve. DETAILED DESCRIPTION
[0044] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.
[0045] Inspired by the functions and characteristics of skin such as moisturizing and flexibility, the present invention discloses a biomass-based flexible hydrogel electrolyte adaptable to extreme environments, comprising gelatin, lithium salt, LiOH·H2O, sodium lignin sulfonate and polyethylene glycol diglycidyl ether; the lithium salt comprises one of lithium bromide and lithium sulfate; the concentrations of the components in the hydrogel electrolyte are as follows: the mass percentage of gelatin is 9.23% to 38.49%; the molar concentration of the lithium salt is 2 mol / L to 16 mol / L; the mass percentage of LiOH·H2O is 0.08% to 0.17%; the mass percentage of sodium lignin sulfonate is 0% to 2.03%; and the mass percentage of polyethylene glycol diglycidyl ether is 0.78% to 2.76%.
[0046] In one embodiment, the lithium salt is lithium bromide.
[0047] Specifically, the lithium bromide (LiBr) added in the present invention is a common refrigerant with low price and low toxicity. LiBr has strong hydration ability and can delay the evaporation of water under high temperature and dry conditions. According to the Hofmeister sequence, bromide ion is a structure-destroying anion that can effectively disrupt the original hydrogen bond arrangement order between water molecules, so that its aqueous solution system has a low freezing point. Lignin has broad prospects for replacing commercial chemical products in various fields due to its low price, renewability, rich functional groups and unique aromatic ring structure. Gelatin is a natural amphiphilic polymer in the skin with a large number of highly hydrophilic groups and the ability to bind water molecules and destroy their hydrogen bond arrangement. Therefore, as a substitute for expensive and energy-intensive petroleum-based chemicals, gelatin and lignin are used to prepare HEs with extreme environmental adaptability, high cost-effectiveness and harmlessness to meet the principles of green chemistry. Inspired by the characteristics of skin, flexible HE designed with gelatin can solve the structural and electrochemical performance defects generated during the deformation of wearable flexible energy storage devices.
[0048] The present invention also discloses a method for preparing the above-mentioned biomass-based flexible hydrogel electrolyte adaptable to extreme environments, comprising the following steps:
[0049] (1) Gelatin, sodium lignin sulfonate and LiOH·H2O were dissolved in deionized water, and then LiBr was added under ice bath conditions and mixed at a stirring speed of 800 rpm to obtain a mixture.
[0050] (2) Adding polyethylene glycol diglycidyl ether to the mixture, covalently crosslinking the mixture at 58° C. to 62° C., to obtain a hydrogel electrolyte.
[0051] In a specific embodiment, in step (1), the dissolving temperature is 58°C to 62°C.
[0052] In a specific embodiment, in step (2), the covalent cross-linking time is 5 h to 8 h.
[0053] Specifically, the hydrogel electrolyte prepared by the preparation method of the present invention has ultra-low modulus, ultra-high elongation at break, antifreeze, anti-dehydration, self-healing and self-regeneration. The physical and mechanical properties, adaptability to extreme environments, cost-effectiveness and green and low-toxicity properties of the multifunctional hydrogel electrolyte prepared by the present invention are far superior to traditional hydrogel electrolytes.
[0054] The present invention also discloses a biomass-based flexible hydrogel electrolyte adapted to extreme environments as described above, or an application of the biomass-based flexible hydrogel electrolyte adapted to extreme environments prepared by the above preparation method in a supercapacitor.
[0055] In a specific embodiment, the application includes:
[0056] Activated carbon, acetylene black and polytetrafluoroethylene powder were mixed in a weight ratio of 8:1:1, dissolved in ethanol, and stirred at room temperature for 12 hours to obtain a slurry.
[0057] The two sides of the hydrogel electrolyte are coated with slurry, and the two sides of the hydrogel electrolyte loaded with slurry are sequentially provided with carbon cloth electrode layers to form a stable interface adhesion, and then a high energy density double-layer supercapacitor with extreme environmental adaptability is obtained through assembly.
[0058] In a specific embodiment, the particle size of the activated carbon is ≥100 mesh, the average particle size of polytetrafluoroethylene is 25 μm, and the average particle size of acetylene black is 35 nm; the thickness of the carbon cloth electrode layer is 0.33 mm to 0.37 mm.
[0059] In a specific embodiment, the elastic modulus of the hydrogel electrolyte is 8.5 kPa; the high elongation at break of the hydrogel electrolyte is 1558%, and the elongation can be recovered to 1030% after breaking and instantaneous self-healing; the ionic conductivity of the hydrogel electrolyte at -50°C is 1.26 mS / cm; the ionic conductivity of the hydrogel electrolyte at 25°C is 26.71 mS / cm.
[0060] The following are specific embodiments
[0061] Example 1
[0062] Materials: Gelatin (≥250 g Bloom), LiBr (99%), Li2SO4 (99.9%), LiOH·H2O (98% AR), sodium lignin sulfonate (molecular weight: 534.5), polyethylene glycol diglycidyl ether (viscosity 40-80 mPa).
[0063] The method for preparing the hydrogel electrolyte of this embodiment comprises the following steps:
[0064] 5.5 g of gelatin, 0.3 g of sodium lignin sulfonate and 0.025 g of LiOH·H2O were completely dissolved in 10 mL of deionized water at 60 ° C with magnetic stirring at 400 rpm. After that, 16 M (10 mL) of LiBr was added under ice bath conditions and stirred at a magnetic stirring speed of 800 rpm to avoid overheating of the mixture. Then, 0.3 g of polyethylene glycol diglycidyl ether was added to the mixture and covalent cross-linked at 60 ° C for 5 h to obtain a skin biomimetic hydrogel electrolyte.
[0065] Embodiment 2-5
[0066] The difference between Example 2-5 and Example 1 is that the amount of LiBr added is changed. Except for the above differences, other operations are the same and will not be repeated here. The amount of LiBr added in Examples 2-5 corresponds to 2M, 4M, 6M, and 8M, respectively.
[0067] Embodiment 6-7
[0068] The difference between Example 6-7 and Example 1 is that the amount of gelatin added is changed. Except for the above differences, other operations are the same and will not be repeated here. The amount of gelatin added in Examples 6-7 corresponds to 2.5g and 7.5g respectively.
[0069] Embodiment 8-9
[0070] The difference between Example 8-9 and Example 1 is that the amount of polyethylene glycol diglycidyl ether added is changed. Except for the above differences, other operations are the same and will not be repeated here. The amount of polyethylene glycol diglycidyl ether added in Examples 8-9 corresponds to 0.25g and 0.4g respectively.
[0071] Examples 10-12
[0072] Compared with Example 1, Examples 10-12 differ in that the amount of sodium lignin sulfonate added is changed. Except for the above differences, other operations are the same and will not be repeated here. The amount of sodium lignin sulfonate added in Examples 10-12 corresponds to 0g, 0.1g, and 0.2g, respectively.
[0073] Comparative Example 1
[0074] The only difference between this comparative example and Example 1 is that LiBr is not added.
[0075] Embodiment 11
[0076] The mechanical properties of the hydrogel electrolytes prepared in Examples 1-12 were analyzed. Figure 1 shown.
[0077] Example 12
[0078] The ionic conductivity of the hydrogel electrolytes prepared in Example 1, Example 2-5, Example 6-7 and Example 10-12 was analyzed. The results are as follows: Figure 2-3 shown.
[0079] Example 13
[0080] The changes in (a) ionic conductivity and (b) mechanical properties of the hydrogel electrolyte prepared in Example 1 before and after healing at different temperatures were analyzed. The results are as follows: Figure 4 shown.
[0081] Embodiment 14
[0082] The adhesion of the hydrogel electrolyte prepared in Example 1 to different materials was analyzed. Figure 5 As shown in (a), the adhesion performance of the hydrogel electrolyte prepared in Example 1 to the carbon cloth electrode at different temperatures was further analyzed. The results are as follows Figure 5 (b) as shown.
[0083] Embodiment 15
[0084] The DSC curves of the hydrogel electrolytes prepared in Examples 1 and 2-5 and the phase transition temperature analysis at extremely low temperatures are shown in the following table: Figure 6 shown.
[0085] Example 16
[0086] The anti-dehydration and self-regeneration performance of the hydrogel electrolytes prepared in Comparative Example 1 and Examples 1-2 were analyzed. Figure 7 As shown, Figure 7 (a) DSC curves of skin-mimetic hydrogel electrolytes with different lithium bromide concentrations (0 M, 2 M and 16 M); (b) the self-regeneration process of skin-mimetic hydrogel electrolytes at 25 °C after dehydration at 60 °C.
[0087] Embodiment 17
[0088] Materials: activated carbon (≥100 mesh), polytetrafluoroethylene (average particle size: 25 μm), acetylene black (99%, average particle size about 35 nm), carbon cloth (thickness: 0.35 mm) and carbon paper (thickness: 0.19 mm).
[0089] The hydrogel electrolyte of Example 1 is applied to a flexible extreme environment adaptable supercapacitor, comprising:
[0090] The hydrogel electrolyte was cut into 1 cm × 1 cm squares with a thickness of about 1 mm. A uniform slurry (about 1 mg / cm 2), the slurry is made by mixing activated carbon, acetylene black and polytetrafluoroethylene powder in a weight ratio of 8:1:1, dissolving in ethanol and stirring at room temperature for 12 hours. The hydrogel electrolyte uniformly loaded with the slurry and the carbon cloth electrodes on both sides can form a stable interface adhesion and assemble into a high energy density double-layer supercapacitor with extreme environmental adaptability.
[0091] Before testing, the supercapacitor was dried at 60°C for 30 min to remove ethanol. To test the self-healing performance of the supercapacitor, the hydrogel electrolyte was subjected to five cutting-healing cycles before being sprayed with slurry and assembled with carbon cloth into a supercapacitor. The remaining steps were exactly the same as the preparation steps of the supercapacitor assembled with uncut hydrogel electrolyte.
[0092] Embodiment 18
[0093] The CV curves, GCD curves and EIS curves of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 under bending conditions of 0°, 90° and 180° are shown as follows: Figure 8 shown.
[0094] Embodiment 19
[0095] The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 at 25°C was analyzed. Fig. 9 As shown, (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0096] Embodiment 20
[0097] The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 at -20°C was analyzed. Fig.10 As shown, (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0098] Embodiment 21
[0099] The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 at 60°C was analyzed. Fig.11 As shown, (a) GCD curve of the original supercapacitor; (b) GCD curve of the supercapacitor after cutting and healing; (c) CV curve of the supercapacitor in the original state; (d) CV curve of the supercapacitor after cutting and healing.
[0100] Embodiment 22
[0101] The EIS curves of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 before and after cutting and healing at 25°C, -20°C and 60°C are as follows: Fig.12 shown.
[0102] Embodiment 23
[0103] The electrochemical performance of the supercapacitor assembled with the skin biomimetic hydrogel electrolyte of Example 17 at an extremely low temperature of -50°C was analyzed. Fig.13 As shown, (a) CV curve; (b) GCD curve; (c) EIS curve.
[0104] According to the analysis results, the skin bionic hydrogel electrolyte of the embodiment of the present invention is used to assemble a flexible supercapacitor with adaptability to extreme environments. It has high energy density even when it experiences extreme deformation, mechanical damage, high temperature, dryness and extremely low temperature environments during its operation, and its electrochemical properties remain stable, and it can still maintain the normal operation of electronic equipment.
[0105] 1. The ultra-soft skin-mimetic hydrogel electrolyte and electrode have matching mechanical properties and stable interface adhesion, which prevents cracks from forming inside the electrolyte or relative displacement between the electrode and the electrolyte during the deformation of the assembled flexible supercapacitor, allowing the supercapacitor to maintain almost consistent electrochemical properties over a wide range of bending angles from 0° to 180°.
[0106] 2. In order to simulate the application scenario of self-repair after damage inside the supercapacitor, the bionic hydrogel electrolyte was cut-healed multiple times and then assembled into a cut-healed supercapacitor in the same way. The results show that under the conditions of 25℃ to -20℃, the electrochemical performance of the original supercapacitor and the cut-healed supercapacitor at different current densities or scan speeds are excellent and highly consistent. Through EIS testing, it was found that the series internal resistance of the original supercapacitor and the cut-healed supercapacitor is not much different, which ensures that the supercapacitor can quickly self-repair when it is mechanically damaged, thereby ensuring the stability of its electrochemical performance.
[0107] 3. The moisture regulation ability of the skin biomimetic hydrogel electrolyte, which is anti-dehydration and hygroscopic, gives the supercapacitor assembled from it excellent electrochemical performance at high temperature and the ability to slowly self-regenerate its electrochemical performance after severe dehydration. The water loss rate of the electrolyte inside the supercapacitor is slow at high temperature, so the electrochemical performance of the supercapacitor can be maintained for a long time without a significant decrease. The mass specific capacitance of the supercapacitor is as high as 231.6F / g (1V voltage) at 60°C. After the capacitor is dehydrated due to long-term operation in a high-temperature dry environment, the internal resistance of the supercapacitor increases, and the drying of the electrode-electrolyte interface causes a decrease in mass transfer efficiency, thereby causing its electrochemical performance to decrease. By transferring it to a normal temperature and humidity environment, the biomimetic hydrogel electrolyte in the supercapacitor can capture water molecules in the air through the pores of the carbon cloth electrode and the electrolyte surface exposed to the air and liquefy on the electrolyte surface, penetrate into the electrode-electrolyte interface and the inside of the electrolyte through the concentration gradient, thereby wetting the electrode-electrolyte interface, effectively reducing the internal ion mass transfer resistance of the supercapacitor, and realizing its electrochemical performance self-regeneration.
[0108] 4. The supercapacitor assembled from skin-inspired hydrogel electrolyte also has excellent electrochemical performance under extremely low temperature conditions of -50°C. Although the internal resistance of the supercapacitor is relatively large at this time, it needs to operate at a higher voltage of 1.6V to overcome the loss caused by the higher voltage drop, but its mass specific capacitance is still as high as 211.3F / g (1.6V), and the energy density is as high as 75.13W / kg (when the power density is 400W / kg), so it can stably power electronic devices for a long time in such an extremely low temperature environment.
[0109] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A biomass-based flexible hydrogel electrolyte adapted to extreme environments, characterized in that: Includes gelatin, lithium salt, LiOH·H2O, sodium lignin sulfonate, and polyethylene glycol diglycidyl ether; The lithium salt includes one of lithium bromide and lithium sulfate; The concentration of each component in the hydrogel electrolyte is as follows: The mass percentage of the gelatin is 9.23% to 38.49%; The molar concentration of the lithium salt is 2 mol / L to 16 mol / L; The mass percentage of the LiOH·H2O is 0.08% to 0.17%; The mass percentage of the sodium lignin sulfonate is 0% to 2.03%; The mass percentage of the polyethylene glycol diglycidyl ether is 0.78% to 2.76%.
2. The biomass-based flexible hydrogel electrolyte adapted to extreme environments according to claim 1, characterized in that: The lithium salt is lithium bromide.
3. A method for preparing a biomass-based flexible hydrogel electrolyte adapted to extreme environments as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: (1) gelatin, sodium lignin sulfonate and LiOH·H2O were dissolved in deionized water, and then LiBr was added under ice bath condition and stirred at 800 rpm to obtain a mixture; (2) Adding polyethylene glycol diglycidyl ether to the mixture, and performing covalent crosslinking at 58° C. to 62° C. to obtain the hydrogel electrolyte.
4. The preparation method according to claim 3, characterized in that: In step (1), the dissolving temperature is 58°C to 62°C; In step (2), the covalent cross-linking time is 5 h to 8 h.
5. An application of a biomass-based flexible hydrogel electrolyte adapted to extreme environments as described in any one of claims 1-2, or a biomass-based flexible hydrogel electrolyte adapted to extreme environments prepared by the preparation method as described in any one of claims 3-4 in a supercapacitor.
6. The use according to claim 5, characterized in that: The applications include: Activated carbon, acetylene black and polytetrafluoroethylene powder were mixed in a weight ratio of 8:1:1, dissolved in ethanol, and stirred at room temperature for 12 hours to obtain a slurry; The slurry is coated on both sides of the hydrogel electrolyte, and carbon cloth electrode layers are sequentially arranged on both sides of the hydrogel electrolyte loaded with the slurry, so as to form a stable interface adhesion, and then a high energy density double-layer supercapacitor with extreme environmental adaptability is obtained through assembly.
7. The use according to claim 6, characterized in that: The particle size of the activated carbon is ≥100 mesh, the average particle size of the polytetrafluoroethylene is 25 μm, and the average particle size of the acetylene black is 35 nm; The thickness of the carbon cloth electrode layer is 0.33 mm to 0.37 mm.
8. The use according to claim 5, characterized in that: The elastic modulus of the hydrogel electrolyte is 8.5 kPa; The hydrogel electrolyte has a high elongation at break of 1558%, and can recover to an elongation of 1030% after breaking and instantaneous self-healing; The ionic conductivity of the hydrogel electrolyte at -50°C is 1.26 mS / cm; The ionic conductivity of the hydrogel electrolyte at 25° C. is 26.71 mS / cm.