Water-in-salt type semi-solid suspension as well as preparation method and application thereof

Abstract

The invention provides a water-in-salt type semi-solid suspension as well as a preparation method and application thereof. The water-in-salt type semi-solid suspension comprises a solid active matter, solid conductive carbon and a water-in-salt type electrolyte, the water-in-salt type electrolyte comprises an electrolyte, water and a cosolvent, the concentration of the water-in-salt type electrolyte is larger than or equal to 10 mol / L, the cosolvent is 1, 3-dioxolane, and the volume ratio of the water to the cosolvent is 1: (1-3). Wherein the addition of the cosolvent molecules changes the bulk phase and interface structure of the salt-in-water type electrolyte, can keep a wide electrochemical stable window at the same time, and has nonflammability and low temperature resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage batteries, and in particular relates to a water-in-salt semi-solid suspension and a preparation method and application thereof. Background Art

[0002] Electrochemical energy storage (EES) technology is an important means to efficiently store electricity generated by clean energy, improve the utilization rate of renewable energy, and solve the instability and intermittency of electricity. It is a key link in the development and utilization of renewable energy. Redox flow batteries (Redox Flow Batteries) are rechargeable batteries that store and release electrical energy through the redox reaction of liquid electrolytes. Its core feature is that energy is stored in the electrolyte and charging and discharging are achieved by external pumping of the electrolyte. It is a new and efficient electrochemical energy storage method with high capacity, wide application field, long cycle life, and decoupling of energy and power. However, its energy density is low (<60Wh / L), which limits the application field of this technology. The structure of the flow battery is as follows Figure 1 As shown, redox active substances with energy are generally dissolved in flowing electrolytes to complete the conversion of chemical energy and electrical energy. In the battery stack, the negative and positive electrolytes are stored in separate external storage tanks. During operation, the positive and negative electrolytes are pumped into the battery stack for reaction, thereby realizing the function of charging and discharging. This structural feature enables it to have the ability to decouple power and energy. However, in liquid flow batteries, energy storage is currently controlled by the amount of soluble active materials in the electrolyte. The calculation of the energy density of liquid flow batteries can be expressed by the following formula:

[0003] Among them, E d is the energy density; n is the number of electron transfers; C i is the concentration of active substance; V 正 / 负极液 is the volume of the positive and negative electrolytes; F is the Faraday constant; E i is the voltage between the positive and negative electrolytes; V 系统 The total volume of the battery system. Improving the energy density of flow batteries is primarily achieved by increasing the number of electron transfers, increasing the concentration of active materials in the positive and negative electrolytes, and raising the voltage between the positive and negative electrolytes. However, the active materials in flow batteries are primarily dissolved in the positive and negative electrolytes, and their energy density is often limited by the solubility of the active materials, hindering further breakthroughs.

[0004] Aiming at the limitations of flow batteries, semi-solid suspension flow batteries are an innovative variant of flow batteries, such as Figure 2As shown, by suspending solid active materials in an electrolyte to form a "slurry" fluid, this method maintains fluidity while significantly improving energy density. Its operating principle combines the "mobile energy storage" characteristics of flow batteries with the "high energy density" advantages of lithium-ion batteries. However, organic electrolytes in suspended slurries face numerous challenges in their application, including flammability, explosiveness, toxicity, and environmental unfriendliness. While aqueous electrolytes in aqueous semi-solid-state battery systems effectively address the shortcomings of organic electrolytes, they do so at the expense of energy density. Because water decomposes at around 1.23V, the electrochemical stability window is narrow, limiting both operating voltage and energy density. Subsequently, researchers proposed a new aqueous electrolyte with an ultra-high salt concentration (21 mol / L), termed "water-in-salt" electrolyte (WiSE). At high salt concentrations, the lack of free water makes it more difficult for water to decompose, which can extend the electrochemical stability window to 3.0V. However, problems such as high viscosity, low conductivity, and salt precipitation at low temperatures limit its practical application. Therefore, it is necessary to develop a new suspension system to solve the problems existing in the existing technology. Summary of the Invention

[0005] The present invention aims to address at least one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a water-in-salt semisolid suspension. By incorporating cosolvent molecules, the bulk and interfacial structure of the water-in-salt electrolyte are modified, thereby simultaneously maintaining a wide electrochemical stability window, non-flammability, and low-temperature resistance.

[0006] The present invention also provides a method for preparing the water-in-salt semi-solid suspension.

[0007] The present invention also provides a water-in-salt semi-solid suspension flow battery.

[0008] The first aspect of the present invention provides a water-in-salt semi-solid suspension, the components of which include a solid active material, solid conductive carbon and a water-in-salt electrolyte, wherein the water-in-salt electrolyte includes an electrolyte, water and a co-solvent, the concentration of the water-in-salt electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane (abbreviated as DOL), and the volume ratio of water to co-solvent is 1:1~3.

[0009] The technical solution of the water-in-salt semi-solid suspension of the present invention has at least the following beneficial effects: The water-in-salt semisolid suspension of the present invention comprises a solid active material, solid conductive carbon, and a water-in-salt electrolyte. The water-in-salt electrolyte comprises an electrolyte, water, and a cosolvent. The cosolvent is an organic solvent added as a cosolvent to WiSE, resulting in an aqueous / non-aqueous mixed electrolyte derived from the WiSE. The addition of the cosolvent molecules modifies the bulk and interfacial structure of the WiSE, enabling it to simultaneously maintain a wide electrochemical stability window, non-flammability, and low-temperature resistance.

[0010] The salt-in-water semi-solid suspension of the present invention has a certain viscosity due to its high salt concentration, which can provide ionic conductivity, uniformly disperse the solid matter in the suspension, and maintain the stability of the slurry suspension. Figure 3 As shown, the use of a high-concentration water-in-salt electrolyte not only fulfills the function of a semi-solid flow battery, but its inherent viscosity allows the active material to occupy a larger volume, reducing the proportion of conductive carbon and providing high energy density. Furthermore, water-in-salt electrolytes expand the range of applicable electrode materials, offer stable cycle life, and are safer. They address the flammability and toxicity issues of organic electrolytes and increase the electrochemical window. This allows water-in-salt electrolytes to overcome the limitations of traditional electrolytes in semi-solid flow batteries.

[0011] According to some embodiments of the present invention, the concentration of the water-in-salt electrolyte is ≥15 mol / L.

[0012] According to some embodiments of the present invention, the concentration of the water-in-salt electrolyte is ≥18 mol / L.

[0013] According to some embodiments of the present invention, the concentration of the water-in-salt electrolyte is ≥21 mol / L.

[0014] The concentration of the water-in-salt electrolyte refers to the concentration of the electrolyte in the water and co-solvent in the water-in-salt electrolyte.

[0015] According to some embodiments of the present invention, the solid active material includes a positive electrode solid active material or a negative electrode solid active material.

[0016] According to some embodiments of the present invention, the positive electrode solid active material includes at least one of LiFePO4, LiMn2O4 and LiCoO2.

[0017] According to some embodiments of the present invention, the negative electrode solid active material includes a selenium-carbon composite material, a sulfur-carbon composite material, Li4Ti5O 12 and at least one of Mo6S8.

[0018] According to some embodiments of the present invention, the electrolyte includes at least one of LiTFSI, LiOTF, LiFSI, LiCl, LiBF4, LiDFOB, and LiClO4.

[0019] According to some embodiments of the present invention, the volume ratio of water to co-solvent is 1:1.

[0020] Co-solvents can help salt-in-water electrolytes withstand low temperatures and lower their crystallization temperature. Adding too much co-solvent will instead reduce the electrochemical performance of the salt-in-water electrolyte. Too little co-solvent will make the electrolyte less resistant to low temperatures, so 1:1 is the preferred ratio.

[0021] The second aspect of the present invention provides a method for preparing the water-in-salt semi-solid suspension of the first aspect of the present invention, comprising the following steps: (1) adding the electrolyte to the water and the co-solvent to obtain the water-in-salt electrolyte; (2) Adding the solid active material and solid conductive carbon to the water-in-salt electrolyte, stirring after ultrasonic vibration, to obtain the water-in-salt semi-solid suspension.

[0022] According to some embodiments of the present invention, the ultrasonic oscillation time is 5 min to 10 min.

[0023] According to some embodiments of the present invention, the ultrasonic oscillation time is any value of 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, such as 8 min, or a range formed by any two of them, such as 6 min~8 min.

[0024] According to some embodiments of the present invention, the stirring time is 20 min to 40 min.

[0025] According to some embodiments of the present invention, the stirring time is any one of 20 min, 25 min, 30 min, 35 min, and 40 min, such as 30 min, or a range formed by any two of them, such as 30 min to 35 min.

[0026] A third aspect of the present invention provides a water-in-salt semi-solid suspension flow battery, comprising a battery reaction unit, a liquid storage system, a circulation system, and the water-in-salt semi-solid suspension of the first aspect of the present invention.

[0027] According to some embodiments of the present invention, a water-in-salt semi-solid suspension flow battery includes a battery reaction unit (i.e., a battery stack), a piping system, and a liquid storage system (including a positive electrode electrolyte storage tank and a negative electrode electrolyte storage tank). The positive electrode electrolyte storage tank and the negative electrode electrolyte storage tank are connected to the battery stack through the piping system, wherein the positive electrode electrolyte storage tank stores positive electrode electrolyte, and the negative electrode electrolyte storage tank stores negative electrode electrolyte.

[0028] The components of the positive electrode electrolyte (i.e., the positive electrode salt-in-water semi-solid suspension system) include a positive electrode solid active material, solid conductive carbon and a salt-in-water electrolyte. The salt-in-water electrolyte includes a positive electrode electrolyte, water and a co-solvent. The concentration of the salt-in-water electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, and the volume ratio of water to co-solvent is 1:1~3.

[0029] The negative electrode electrolyte components (i.e., the negative electrode salt-in-water semi-solid suspension system) include a negative electrode solid active material, solid conductive carbon and a salt-in-water electrolyte. The salt-in-water electrolyte includes a negative electrode electrolyte, water and a co-solvent. The concentration of the salt-in-water electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, and the volume ratio of water to co-solvent is 1:1~3. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural diagram of a flow battery.

[0031] Figure 2 This is a schematic diagram of the structure of a semi-solid liquid flow battery.

[0032] Figure 3 This is a conceptual diagram of a water-in-salt semi-solid suspension flow battery.

[0033] Figure 4 Se-C / / LFP full cell in 10M BSiS-DOL 0.5 0.05 mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0034] Figure 5 Se-C / / LMO full cell in 10M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0035] Figure 6 It is SC / / LMO full battery in 10M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0036] Figure 7 Se-C / / LMO full cell in 5M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0037] Figure 8 Se-C / / LMO full cell in 10M BSiS-DOL 0.25 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0038] Figure 9 Se-C / / Li half-cell in 10M electrolyte 0.2mA / cm 2 Constant current charge and discharge curves at current density.

[0039] Figure 10 This is a schematic diagram of the battery's non-flammability and low-temperature resistance test results.

[0040] Figure 11 This is a schematic diagram of the experimental results of low-temperature testing of four electrolytes. DETAILED DESCRIPTION

[0041] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0042] In existing technologies, the energy density of liquid flow batteries is limited by the solubility of the active material. Semi-solid suspension flow batteries improve energy density by introducing solid active materials, but organic electrolytes are flammable and toxic. Aqueous electrolytes, while safer, are limited by a narrow electrochemical stability window and lower energy density.

[0043] To address these issues, it is necessary to develop an electrolyte system that combines high energy density with safety. While the high concentration of salt-in-water electrolytes can inhibit water decomposition, their poor fluidity needs to be addressed. By introducing specific co-solvents, the physical properties of the electrolyte can be adjusted while maintaining the voltage stability brought about by high salt concentrations. Furthermore, the synergistic effect of solid-state active materials and conductive carbon must form a stable suspension in the electrolyte to achieve efficient charge transfer.

[0044] Therefore, the present invention proposes a water-in-salt semi-solid suspension, wherein the components of the water-in-salt semi-solid suspension system include a solid active material, solid conductive carbon and a water-in-salt electrolyte, wherein the water-in-salt electrolyte includes an electrolyte, water and a co-solvent, the concentration of the water-in-salt electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, the volume ratio of water to the co-solvent is 1:1~3, and the concentration of the water-in-salt electrolyte reaches or exceeds a specific threshold.

[0045] Among them, salt-in-water type electrolyte refers to an electrolyte system with a high concentration of electrolyte as the main component and water as the secondary component. Specifically, it can be achieved by, for example, mixing lithium salt with a specific solvent. Its high salt concentration can inhibit the decomposition reaction of water. Co-solvent refers to an organic solvent that is miscible with water and can reduce the viscosity of the system. For example, 1,3-dioxolane can improve the fluidity of the electrolyte and inhibit salting out at low temperatures. The volume ratio of water to co-solvent is controlled in the range of 1:1 to 3. Using a ratio of 1:1 can balance the viscosity and ionic conductivity of the electrolyte. Solid active matter refers to solid particles with redox ability. For example, lithium iron phosphate is used as the positive electrode active material to achieve high loading through suspension. Solid conductive carbon refers to carbon-based conductive additives, such as carbon nanotubes or carbon black, which are used to construct a conductive network to improve charge transfer efficiency.

[0046] Specifically, the water-in-salt electrolyte can extend the electrochemical window to above 3.0V by limiting the activity of free water molecules through high-concentration electrolytes. The introduction of the co-solvent 1,3-dioxolane reduces the viscosity of the system, and the synergistic effect with water maintains the stability of the electrolyte at low temperatures. The solid active material is dispersed in the electrolyte to form a semi-solid suspension system, and its loading capacity is not limited by solubility. The solid conductive carbon ensures electronic conduction between the active materials through a three-dimensional conductive network. When preparing the water-in-salt semi-solid suspension, ultrasonic vibration can be used to evenly disperse the solid components, and the stirring process can promote full contact between the electrolyte and the solid particles.

[0047] Compared to existing technologies, conventional electrolytes increase pumping energy consumption due to their high viscosity. This invention significantly reduces viscosity through co-solvent regulation while maintaining the voltage stability afforded by high concentrations. Compared to organic electrolyte systems, the aqueous co-solvent system employed in this invention eliminates flammability risks and overcomes solubility energy density limitations through the suspension of solid active ingredients.

[0048] Through the above technical solution, the present invention improves the electrolyte's fluidity and low-temperature suitability while maintaining a wide voltage window. Furthermore, it achieves high energy density storage through a solid-state active material suspension system. This electrolyte system combines safety, high ionic conductivity, and stable suspension properties, providing a viable solution for the practical application of semi-solid-state flow batteries.

[0049] The present invention further proposes that the solid active material includes a positive electrode solid active material or a negative electrode solid active material.

[0050] Among them, the positive electrode solid active material refers to the solid active material that is reduced during the battery discharge process. Specifically, it can be realized by using materials such as lithium iron phosphate and transition metal oxides. Its function is to provide the active sites required for the redox reaction of the positive electrode.

[0051] Among them, the negative electrode solid active material refers to the solid active material that is oxidized during the battery discharge process. Specifically, it can be realized by using selenium-carbon composite materials, metal sulfides and other materials. Its function is to provide the active sites required for the redox reaction of the negative electrode.

[0052] Specifically, in a salt-in-water semi-solid suspension system, the positive electrode solid active material and the negative electrode solid active material are disposed in the positive and negative electrode suspension systems, respectively. The positive electrode active material participates in the reaction by embedding or extracting lithium ions during the charge and discharge process, while the negative electrode active material releases or stores electrons through oxidation or reduction reactions. Due to the differences in the electrochemical properties of the positive and negative electrode active materials, their separate configuration avoids energy loss due to cross-reactions. At the same time, by optimizing the compatibility of the active material with the electrolyte, the stable flow characteristics of the suspension are maintained.

[0053] Compared to existing technologies, conventional semi-solid-state flow battery suspension systems typically utilize a single type of active material, without clearly distinguishing the functional differences between the positive and negative electrode active materials. This can lead to side reactions in the active materials during charge and discharge, reducing energy conversion efficiency. By independently selecting and matching the positive and negative electrode active materials, the present invention improves active material utilization while reducing interfacial side reactions caused by material incompatibility.

[0054] Through the above-mentioned technical solution, the present invention achieves a directional configuration of positive and negative electrode active materials, enabling the electrolyte system to be optimized for the electrochemical reaction requirements of different electrodes, thereby improving the overall energy density and cycle stability of the battery. Furthermore, the independent selection of positive and negative electrode active materials provides a material design foundation for the development of high-voltage, high-capacity semi-solid-state flow batteries.

[0055] The present invention further proposes that the positive electrode solid active material includes at least one of LiFePO4, LiMn2O4 and LiCoO2.

[0056] Among them, LiFePO4 refers to lithium iron phosphate material, which can be prepared by solid-phase method or sol-gel method. It has a stable olivine crystal structure and can provide reversible lithium ion insertion / extraction capabilities, thereby improving the cycle stability of the positive electrode material.

[0057] Specifically, in a salt-in-water electrolyte system, the positive electrode solid active material is dispersed in the electrolyte in the form of solid particles, and charge storage is achieved through the migration of lithium ions at the solid-liquid interface. Due to its low structural strain and high thermal stability, LiFePO4 can effectively suppress particle breakage caused by volume changes during charge and discharge, thereby maintaining the integrity of the electrode structure.

[0058] Compared to existing technologies, the cathode active material in traditional flow batteries typically exists in a dissolved state in the electrolyte, where its concentration is limited by solubility and is prone to side reactions. This invention, however, uses a solid active material as an energy carrier, not only overcoming solubility limitations but also avoiding corrosion of the electrode material by water decomposition through the expanded electrochemical window of a salt-in-water semi-solid suspension. This improves energy density while enhancing system stability.

[0059] Through the above technical solution, the present invention can significantly improve the carrier storage capacity and cycle life of the positive electrode material without sacrificing safety and environmental friendliness, and at the same time meet the differentiated requirements of energy density and power density in diverse application scenarios through the combination of different active materials.

[0060] The present invention further proposes that the negative electrode solid active material includes selenium-carbon composite material, sulfur-carbon composite material, Li4Ti5O 12 and at least one of Mo6S8.

[0061] Selenium-carbon composite materials are composite structures with selenium as the active material and carbon materials as the carrier. Specifically, they are achieved by loading selenium into a porous carbon matrix using chemical deposition. The porous structure of the carbon material mitigates the volume expansion of selenium during charge and discharge, while also improving electron conduction efficiency.

[0062] Specifically, in a water-in-salt semi-solid suspension flow battery system, the negative electrode solid active material must meet the requirements of high electrochemical activity, structural stability, and compatibility with high-salt concentration electrolytes. In selenium-carbon composite materials, the high theoretical specific capacity of selenium combined with the conductivity and mechanical support of carbon materials can effectively inhibit the pulverization and shedding of active materials during the cycle. At the same time, the hydrophobic properties of the carbon skeleton can reduce direct contact between the active material and water in the electrolyte, thereby reducing the probability of side reactions. During the preparation process, selenium can be evenly dispersed in the pores of the carbon matrix through melt impregnation, forming a stable composite structure.

[0063] Compared to existing technologies, traditional flow battery anodes often use dissolved active materials, whose concentration is limited by solubility and suffers from self-discharge. Metal oxide anode materials in existing semi-solid systems also suffer from poor conductivity and high volume expansion. By introducing a selenium-carbon composite material, the present invention retains the high energy density advantages of solid-state active materials while improving the material's cycling stability through the conductive network and confinement effects of the carbon matrix.

[0064] Through this technical solution, the present invention addresses the issues of insufficient conductivity and structural damage caused by volume expansion in conventional semi-solid-state flow battery anode materials, while also avoiding the safety hazards associated with organic electrolyte systems. The synergistic effect of the selenium-carbon composite and the salt-in-water electrolyte maintains anode interface stability, thereby improving the battery's cycle life and energy density.

[0065] The present invention further proposes that the electrolyte in the electrolyte includes at least one of LiTFSI, LiOTF, LiFSI, LiCl, LiBF4, LiDFOB and LiClO4.

[0066] Among them, LiTFSI refers to lithium bis(trifluoromethanesulfonyl)imide, which can be dissolved in the electrolyte in the form of a powder with a purity higher than 99%. It has high solubility, low viscosity and good electrochemical stability, and can maintain high ion mobility in the salt-in-water system and inhibit the water decomposition reaction.

[0067] Specifically, when LiTFSI is dissolved as an electrolyte in a mixture of water and a co-solvent, its high degree of dissociation reduces the internal resistance of the electrolyte. It also synergizes with the co-solvent 1,3-dioxolane to inhibit salt crystallization at high salt concentrations. For example, in a 1:1 volume ratio of water to co-solvent, the concentration of LiTFSI can reach saturation, forming a stable ion transport network, thereby ensuring the electrode reaction kinetics during the charge and discharge processes of semi-solid suspension flow batteries.

[0068] Compared to existing technologies, traditional salt-in-water electrolytes often use a single high-concentration salt, such as LiTFSI, without a co-solvent system to optimize dissolution behavior, leading to salting out or viscosity surges at low temperatures. This invention, by introducing a specific co-solvent and matching the LiTFSI concentration, maintains a high electrochemical window while improving the electrolyte's fluidity and low-temperature stability.

[0069] Through the above technical solution, the present invention solves the problem of increased viscosity and decreased conductivity of salt-in-water electrolyte at high concentrations, while avoiding salting out, so that the semi-solid suspension flow battery maintains stable ion transfer efficiency and cycle performance over a wide temperature range.

[0070] The present invention further proposes that the volume ratio of water to the co-solvent is 1:1.

[0071] 1,3-Dioxolane is used as a co-solvent. The oxygen-containing heterocyclic structure in its molecular structure can form a hydrogen bond network with water molecules. Specifically, the viscosity and ion transport capacity of the electrolyte system can be optimized by adjusting the strength of its interaction with water.

[0072] Specifically, in a water-in-salt electrolyte system, when the volume ratio of water to cosolvent is adjusted to 1:1, this ratio enables the free water molecules in the electrolyte to form a stable solvation structure with the cosolvent molecules. Under these conditions, the electrolyte system maintains sufficient ion migration channels while also reducing the viscosity increase caused by high salt concentrations through the dilution effect of the cosolvent. By controlling the stirring time of the mixed solution and the ultrasonic dispersion process, it is possible to ensure that the solid active material particles form a uniformly dispersed semi-solid suspension system in the electrolyte.

[0073] Compared to existing technologies, traditional salt-in-water electrolytes typically use a single solvent or an unbalanced ratio. For example, using excessive water can narrow the electrochemical window, or excessive co-solvents can cause a sharp increase in viscosity. However, by limiting the volume ratio, the present invention achieves a synergistic optimization of electrolyte viscosity and ionic conductivity while maintaining a high-concentration salt structure.

[0074] Through the above technical solution, the present invention effectively balances the contradiction between the flow characteristics and electrochemical stability of the electrolyte system, enabling the semi-solid suspension flow battery to maintain stable ion transmission efficiency during the charge and discharge process while avoiding the problem of active material sedimentation caused by local viscosity differences.

[0075] The present invention further proposes a method for preparing a water-in-salt semi-solid suspension, comprising the following steps: first, adding an electrolyte to water and a co-solvent to obtain a water-in-salt electrolyte; then, adding a solid active substance and solid conductive carbon to the water-in-salt electrolyte, and stirring after ultrasonic vibration to obtain the water-in-salt semi-solid suspension.

[0076] Among them, salt-in-water type electrolyte refers to a mixed system composed of high-concentration electrolyte, water and co-solvent. Specifically, it can be achieved by dissolving the electrolyte in a mixture of water and 1,3-dioxolane co-solvent. This system expands the electrochemical window by limiting the free water content. Ultrasonic oscillation refers to the use of high-frequency sound wave energy to disperse solid active material particles. Specifically, it can be achieved by using an ultrasonic instrument with a frequency range of 20-40kHz. This step can effectively break up particle agglomeration and promote uniform distribution of conductive carbon. Stirring refers to maintaining the stability of the suspension through mechanical action. Specifically, it can be achieved by using magnetic stirring or paddle stirring devices. This step can prevent the active material from settling and maintain the fluidity of the electrolyte.

[0077] Specifically, the electrolyte can first be dissolved in water and co-solvents pre-mixed in proportion to form a high-concentration salt-in-water electrolyte base. Subsequently, solid active material powder and conductive carbon material are gradually added to the electrolyte, and ultrasonic treatment is used to fully disperse the solid particles and form a stable suspension system. Finally, continuous stirring is used to further optimize the slurry uniformity to ensure that the active material and conductive agent form a three-dimensional conductive network in the electrolyte. This method achieves efficient combination of solid and liquid phases while avoiding the influence of high viscosity through a step-by-step mixing process.

[0078] Compared to existing technologies, traditional suspension flow battery preparation often faces difficulties dispersing solid particles due to the high viscosity of organic electrolytes. Conventional aqueous electrolytes, on the other hand, require the addition of dispersants to maintain suspension stability. This method leverages the low free water content of salt-in-water electrolytes to suppress side reactions. Combined with the synergistic effects of ultrasonic vibration and stirring, this method achieves uniform dispersion of the active material without the need for dispersants, while also avoiding the environmental risks of organic solvents.

[0079] Through the above technical solution, the present invention solves the problem of uneven solid-liquid mixing caused by the high viscosity of salt-in-water electrolytes, effectively improving the utilization rate of active materials in semi-solid suspension flow batteries. The electrolyte prepared by this method maintains high energy density while exhibiting good flow properties, providing a feasible process path for building safe and stable aqueous semi-solid-state battery systems.

[0080] The present invention further proposes that when preparing the electrolyte of the water-in-salt semi-solid suspension flow battery, the ultrasonic oscillation time is controlled to be 5 minutes to 10 minutes.

[0081] The ultrasonic oscillation duration refers to the duration of ultrasonic treatment to uniformly disperse the solid active material and solid conductive carbon in the electrolyte. Specifically, ultrasonic treatment for 5 to 10 minutes can achieve this. This time range effectively breaks up particle agglomerations while avoiding material structure damage or energy waste caused by excessively long treatment times.

[0082] Specifically, after adding the solid active material and solid conductive carbon to the salt-in-water electrolyte, ultrasonic agitation is used to evenly disperse the particles. If the agitation time is too short, the particles may not fully deagglomerate, resulting in a decrease in electrolyte conductivity. If the agitation time is too long, the surface structure of the active material may be damaged or the co-solvent may evaporate. For example, after 8 minutes of ultrasonic treatment, the particle dispersion reaches its optimal state. At this point, the agitation is stopped and the stirring step is initiated to ensure the stability of the suspension system.

[0083] Compared with existing technologies, the ultrasonication time in traditional semi-solid electrolyte preparation is usually not clearly defined, which may lead to insufficient dispersion or excessive treatment. By limiting the time range, the present invention not only improves the dispersion efficiency but also avoids material damage or increased energy consumption caused by uncontrolled time.

[0084] Through the above technical solution, the present invention achieves uniform distribution of solid active materials and conductive carbon in the electrolyte, thereby improving the battery charging and discharging efficiency while reducing energy loss and material waste in the preparation process.

[0085] The present invention further proposes that the stirring time is 20 min to 40 min.

[0086] The stirring time refers to the duration of mechanical stirring after the solid active material and solid conductive carbon are mixed with the salt-in-water electrolyte. This can be achieved using a magnetic stirrer or a mechanical stirrer. Stirring time that is too short may result in uneven dispersion of the materials, while stirring time that is too long may cause volatilization or decomposition of electrolyte components. A stirring time within the range of 20 to 40 minutes can ensure that the solid active material and conductive carbon are fully dispersed in the electrolyte while avoiding the negative effects of prolonged stirring.

[0087] Specifically, when preparing a salt-in-water semi-solid suspension, the solid active material and conductive carbon must be evenly dispersed in a high-concentration electrolyte to form a stable suspension system. Controlling the stirring time within the range of 20 to 40 minutes allows the solid particles to fully contact the electrolyte and form a homogeneous mixture. For example, when the stirring time is less than 20 minutes, the conductive carbon may form local agglomerations due to insufficient dispersion, affecting electron conduction; while when it exceeds 40 minutes, the co-solvent in the electrolyte may evaporate due to continuous mechanical action, resulting in an increase in the viscosity of the system. By limiting this time range, it is possible to maintain the physical and chemical stability of the electrolyte while ensuring the dispersion effect.

[0088] In some embodiments, the stirring process can be controlled by a thermostat, for example, maintaining the temperature at 25° C. to prevent solvent volatilization. The stirring speed can be set to 200-500 rpm, depending on the container size and the type of stirring blade.

[0089] Compared to existing technologies, conventional semi-solid electrolyte preparation often relies on fixed stirring times or empirical procedures, such as stirring for only 10 minutes or extending the stirring time to more than an hour. The former can lead to uneven material dispersion, while the latter increases energy consumption and may damage the electrolyte components. The present invention, which has been experimentally verified to have a stirring time range of 20 to 40 minutes, strikes a balance between dispersion efficiency and stability, making it particularly suitable for high-viscosity salt-in-water electrolyte systems.

[0090] Through the above technical solution, the present invention solves the problem of uneven material dispersion or component degradation caused by improper stirring time during the preparation of semi-solid electrolyte, ensures the uniform distribution of solid active substances and conductive carbon, thereby improving the consistency of the electrochemical performance of the electrolyte and providing a reliable slurry basis for subsequent battery assembly.

[0091] The present invention further provides a water-in-salt semi-solid suspension flow battery, comprising a battery reaction unit, a liquid storage system, a circulation system, and the water-in-salt semi-solid suspension of the present invention.

[0092] Specifically, the salt-in-water type semi-solid suspension flow battery includes a battery reaction unit (i.e., a battery stack), a piping system, and a liquid storage system (including a positive electrode electrolyte storage tank and a negative electrode electrolyte storage tank). The positive electrode electrolyte storage tank and the negative electrode electrolyte storage tank are connected to the battery stack through the piping system, wherein the positive electrode electrolyte storage tank stores positive electrode electrolyte, and the negative electrode electrolyte storage tank stores negative electrode electrolyte.

[0093] The components of the positive electrode electrolyte (i.e., the positive electrode salt-in-water semi-solid suspension system) include positive electrode solid active material, solid conductive carbon and salt-in-water electrolyte. The salt-in-water electrolyte includes positive electrode electrolyte, water and co-solvent. The concentration of the salt-in-water electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, and the volume ratio of water to co-solvent is 1:1~3.

[0094] The negative electrode electrolyte components (i.e., the negative electrode salt-in-water semi-solid suspension system) include negative electrode solid active material, solid conductive carbon and salt-in-water electrolyte. The salt-in-water electrolyte includes negative electrode electrolyte, water and co-solvent. The concentration of the salt-in-water electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, and the volume ratio of water to co-solvent is 1:1~3.

[0095] Through the above technical solution, the salt-in-water semi-solid suspension flow battery of the present invention solves the application limitations of traditional semi-solid flow batteries caused by the flammability of organic electrolytes and the low energy density of aqueous electrolytes, and achieves the compatibility of high energy density and high safety. At the same time, the physical properties of the electrolyte are optimized by co-solvents to avoid the problems of increased viscosity and low-temperature salting out caused by high salt concentration.

[0096] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0097] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0098] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0099] Unless otherwise specified, “about” in the present invention means that the allowable error is within ±2%.

[0100] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0101] Example 1 A water-in-salt semisolid suspension (WiSE) for use in water-in-salt semisolid suspension flow batteries was prepared. Based on the preparation and testing of the WiSE semisolid suspension, two compatible solid and liquid active materials with high theoretical capacities and small differences in redox potentials were combined. This example demonstrates the WiSE semisolid suspension flow battery using a Se-C and LiFePO4 full cell.

[0102] LiFePO4 as the positive electrode active material has abundant resources, low cost, theoretical capacity of 170mAh / g, and high redox potential (about 3.45 V vs. Li / Li + ), has the advantage of good cycle stability, which has a great advantage in achieving the stability of the suspension; and Se as the negative electrode active material has a low price and density (4.82g / cm 3 ) and conductivity (1×10 -5 S / cm). Compared with S, Se has higher density, melting point and boiling point, is stable and safe, and its electrical conductivity is 20 orders of magnitude higher.

[0103] In this embodiment, 10M LiTFSI was dissolved in H2O / DOL (volume ratio 1:1) as the liquid electrolyte, recorded as 10M BSiS-DOL 0.5 , where "BSiS" stands for salt-in-water, and "DOL 0.5 ” means the ratio of H2O to DOL in the solvent is 1:1.

[0104] The positive electrode solid active material LiFePO4 and the negative electrode solid active material Se-C were added respectively to prepare the positive electrode WiSE suspension and the negative electrode WiSE suspension.

[0105] The preparation process of the WiSE semi-solid suspension is as follows: (1) A 10 M lithium salt electrolyte (10 M BSiS-DOL) was prepared by adding bis(trifluoromethylsulfonyl) (LiTFSI) to a solution of pure water and 1,3-dioxolane (DOL) in a volume ratio of 1:1. 0.5 ); (2) Add 1 mol / L of the positive electrode solid active material LiFePO4 and 1 mol / L of the negative electrode solid active material Se-C to the above electrolyte to obtain a positive electrode WiSE suspension and a negative electrode WiSE suspension; (3) Ultrasonic vibration for 5-10 minutes and magnetic stirring for 30 minutes were used to form a uniform, stable and non-stratified positive electrode WiSE suspension and negative electrode WiSE suspension.

[0106] In this example, a flow battery was assembled using the prepared LFP salt-in-water suspension as the cathode solution and the Se-C salt-in-water suspension as the anode solution, and the WiSE suspension flow battery was tested for charge and discharge. Figure 4 shown. Figure 4 Se-C / / LFP full cell in 10M BSiS-DOL 0.5 0.05 mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0107] It should be noted that the Se-C / / LFP full battery is a preliminary study to explore whether the electrolyte is suitable for positive and negative electrode active materials. Therefore, a lower current density (0.05 mA / cm 2 ) was first tried. It was found that the performance was good, so subsequent examples further used higher current densities to test the performance of the battery.

[0108] from Figure 4 It can be seen from the constant current charge and discharge curve that Se-C / / LFP full battery is 0.5 The battery can operate stably in electrolyte, with a battery voltage of 1.05 V and an initial capacity of 125 mAh / g, which can reach 75% of the theoretical capacity. After 20 cycles, the overpotential of the battery did not increase, and the average decay rate was 1.4%, maintaining 78% of the initial capacity. There was no polyselenide shuttle causing battery failure. 0.5 The electrolyte is compatible with both Se-C and LFP active materials.

[0109] The present invention also tests the non-flammability and low temperature resistance of the battery, such as Figure 10 As shown, 10 MBSiS-DOL 0.5 , WiSE, 1M LiTFSI TEGDME and 1M LiPF6EC / DEC electrolytes were subjected to flame retardancy comparison experiments, and 300 microliters of each electrolyte was tested on a glass fiber with a diameter of 19 mm. As can be seen from the figure, the two organic solvents 1M LiTFSITEGDME and 1M LiPF6EC / DEC electrolytes immediately burned violently after encountering high-temperature open flames. Even after the external fire source was extinguished, the fire continued to grow, indicating extremely low safety. However, 10 M BSiS-DOL 0.5 The addition of DOL did not hinder the 10 M BSiS-DOL 0.5 The electrolyte inherits the non-flammability of aqueous solution.

[0110] like Figure 11 As shown, for 10M BSiS-DOL 0.5 Low temperature test experiments were carried out on four electrolytes: WiSE, 1M LiTFSI TEGDME and 1M LiPF6EC / DEC. Figure 11 In the figure, (a) shows the state of the four electrolytes at -4°C. It can be seen that WiSE has become a solid crystal at this low temperature, which is related to the natural low freezing point of water solvent (0°C). The 10M BSiS-DOL with the addition of DOL 0.5 The electrolyte and two non-aqueous electrolytes all showed completely liquid state. Figure 11 In the figure, (b) is the state under ultra-low temperature of -40℃, and it can be seen that the results are consistent with those under -4℃. The addition of DOL greatly reduces the 10 M BSiS-DOL 0.5 The crystallization temperature of the electrolyte allows it to remain completely liquid even in ultra-low temperature environments such as -40°C, providing stable operating conditions for the battery at low temperatures.

[0111] Example 2 The difference from Example 1 is that the positive electrode active material is LiMn2O4, or LMO. LMO is considered a promising lithium-ion battery positive electrode material due to its good stability, good overcharge resistance, low price, environmental friendliness, and good high-current charge and discharge performance.

[0112] The Se-C / / LMO full cell voltage of this embodiment reaches 1.8V, which is higher than the voltage of most aqueous batteries.

[0113] By similar preparation method of WiSE suspension, we obtained the test results of WiSE suspension as follows: Figure 5 shown. Figure 5 Se-C / / LMO full cell in 10M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0114] from Figure 5 It can be seen that LMO cathode active material can amplify 10 M BSiS-DOL better than LFP 0.5 Advantages of electrolyte. The operating voltage of Se-C / / LMO full battery can reach 1.8V, the initial actual capacity is 143mAh / g, reaching 97% of the theoretical capacity, the average decay rate within 50 cycles is 0.046%, and the capacity retention rate after 50 cycles is 87% of the original capacity. The average coulombic efficiency reaches 97%. The overpotential of this battery is smaller than that of Se-C / / LFP full battery, showing stable battery cycle performance. It is proved that using 10M BSiS-DOL 0.5 Using electrolyte to assemble a full battery system with high voltage and high cycle stability is a feasible solution.

[0115] Example 3 The difference from Example 1 is that SC is used as the negative electrode active material. 0.5 Salt-in-water electrolyte with a wide cathode limit of 5.3V vs. Li / Li + , which has met the working voltage requirements of most positive electrode active materials. Its cathode side limit is 0.76Vvs.Li / Li + It can withstand extremely low potential, making its electrochemical stability window reach 4.6V, which can greatly expand the selection of positive and negative active materials. For example, Se in the negative electrode material can be replaced by S, a member of the same family. The common Li4Ti5O 12， Mo6S8 and other materials can also be used instead. LiNi in the positive electrode active material 0.5 Mn 1.5 O4, LiVOPO4 and other materials can be used instead. At the same time, it can also improve the cycle stability of the battery, and can choose cheaper active materials as positive and negative electrodes, which is of great significance for the promotion of salt-in-water semi-solid suspension flow batteries. Figure 6 shown. Figure 6 It is SC / / LMO full battery in 10M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0116] from Figure 6 As can be seen, the addition of SC / / LMO to the full cell demonstrates excellent electrochemical performance, with a stable operating voltage of 1.5 V and an initial actual capacity of 1408 mAh / g, reaching 83.9% of the theoretical capacity. The average decay rate over 50 cycles was 5.7%, and after 50 cycles, the capacity retained 55% of the initial capacity. There was no significant increase in overpotential, and the reduced shuttling of polysulfides significantly improved cycle life, with Coulombic efficiency maintained above 97%.

[0117] It should be noted that the 0.2 mA / cm 2 The current density is 4 times higher than that of Example 1, which greatly shortens the charge and discharge time of one cycle. The assembled full battery also exhibits better initial capacity, capacity retention and other performance.

[0118] Comparative Example 1 Compared with Example 1, the difference is that the concentration of the salt-water electrolyte is 5M BSiS-DOL 0.5 .

[0119] Figure 7 Se-C / / LMO full cell in 5M BSiS-DOL 0.5 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0120] The test results show that using 5M BSiS-DOL 0.5 As the electrolyte, the voltage of Se-C / / LMO full battery reaches 1.65V, and the initial charge capacity is 130 mAh / g, which can reach 87.8% of the theoretical capacity. Figure 7 As can be seen, water decomposition has already occurred. Compared to the number of salt ions in the solution, the number of free water molecules in the solution is greater, making them more likely to bind to lithium ions. The hydration of lithium ions results in a Coulombic efficiency of only 42% in the first cycle. After the second cycle, the attenuation rate reaches 20%, and the capacity remains at 77.8% of the initial capacity.

[0121] Comparative Example 2 Compared with Example 1, the difference is that the ratio of H2O to DOL is not 1:1, but 3:1.

[0122] The test results show that using 10M BSiS-DOL 0.25 As the electrolyte, the full cell voltage of Se-C / / LMO was 1.7V, compared with that of 10 M BSiS-DOL. 0.5 The voltage of the electrolyte-assembled Se-C / / LMO full cell dropped by 0.1V.

[0123] Figure 8Se-C / / LMO full cell in 10M BSiS-DOL 0.25 0.2mA / cm in electrolyte 2 Constant current charge and discharge curves at current density.

[0124] from Figure 8 Similar to Comparative Example 1, water decomposition occurred during the charging process. The initial actual capacity of 135 mAh / g reached 91% of the theoretical capacity, and the initial coulombic efficiency was only 57%. Due to the presence of DOL, the water decomposition situation was slightly better than that of Comparative Example 1. The battery did not show significant degradation until the third cycle, with the capacity remaining at 88% of the initial capacity.

[0125] Comparative Example 3 Compared with Example 1, the difference is that there is no co-solvent 1,3-dioxolane.

[0126] Figure 9 Se-C / / Li half-cell in 10M electrolyte 0.2mA / cm 2 Constant current charge and discharge curves at current density.

[0127] The test results show that when DOL is not added, Figure 9 In (a), it can be seen that the initial actual capacity of 220 mAh / g under pure WiSE conditions only reaches 32% of the theoretical capacity. After 20 cycles of charge and discharge, the capacity decays to 19% of the initial capacity, and the cycle stability is poor. Figure 9 (b) is BSiS-DOL with co-solvent DOL added 0.5 Electrolyte. Through obvious curve comparison, it can be found that after adding the co-solvent DOL, the battery performance has been greatly improved, and the initial capacity of 527mAh / g has reached 77.7% of the theoretical capacity. And the battery decay rate slowed down after 20 cycles, and the capacity maintained 85% of the initial capacity. Due to the addition of co-solvent, the capacity of the battery increased by 45.7%, and the capacity retention after 20 cycles was also improved by 66%. Compared with the BSiS-DOL without adding DOL, the BSiS-DOL with DOL 0.5 The overpotential of electrolyte cells increases only slowly during cycling.

[0128] It should be noted that this is just an example of assembling a full battery with a salt-in-water electrolyte, and its positive and negative active materials can be replaced.

[0129] When preparing salt-in-water suspensions, the principles for selecting suitable positive and negative active material materials can be referred to as: high stability, high ionic conductivity, high theoretical capacity, abundant resources, low cost, and the ability to form a stable and uniform suspension state with three-dimensional conductive carbon in the electrolyte.

[0130] The key point of this invention lies in the concept of a water-in-salt semi-solid suspension flow battery. Using a water-in-salt electrolyte instead of traditional organic and aqueous electrolytes improves battery safety and environmental friendliness. By leveraging the inherent high viscosity of the water-in-salt electrolyte, reducing the amount of conductive carbon added allows for better suspension formation. Active material can replace some of the original conductive carbon volume, providing additional capacity and further increasing the battery's energy density.

[0131] It should be noted that in previous work, by dissolving a high concentration of LiTFSI in water / non-aqueous DOL (1,3-dioxolane) as a salt-in-water electrolyte (BSiS-DOL0.5), and mixing it with a solid Se-C complex to form a negative electrode semi-solid suspension, a salt-in-water semi-solid suspension flow battery was established with the LMO positive electrode material, achieving an energy density of 144Wh / L (in existing technologies, the energy density of traditional liquid flow batteries is about 25~60Wh / L), successfully demonstrating its feasibility.

[0132] In the Se-C / / LMO salt-in-water semi-solid suspension flow battery, the high-concentration LiTFSI aqueous / non-aqueous solution not only provides ionic conductivity for the battery reaction and maintains the uniformity of the suspension, but also provides additional energy contribution to the system during the cycle. It was unexpectedly discovered that the presence of the co-solvent DOL inhibits the dissolution of short-chain polyselenides to a certain extent. The salt-in-water electrolyte with the addition of a co-solvent inherits the non-flammability of water and the low-temperature resistance of the non-aqueous co-solvent. However, due to the electrochemical stability window of 4.6V of the salt-in-water electrolyte, the assembled Se-C / / LMO salt-in-water semi-solid suspension flow battery reaches a voltage of 1.8V, which does not maximize its utilization. Therefore, further exploration of new electrode materials requires that their redox potential be precisely located within the electrochemical stability window of the water / non-aqueous mixed electrolyte.

[0133] The suspension of the present invention is basically applicable to all liquid flow batteries. The basic principle is to place excess active material in the form of slurry in the suspension to obtain higher energy density.

[0134] 1) The potential difference between the positive and negative active materials cannot exceed 3V, otherwise it may easily cause the electrolyte to decompose; 2) The selection of positive and negative electrode active materials must ensure that they do not produce harmful side reactions with the WiSE used in this invention and are compatible with the aqueous solvent. The negative electrode active material must not have a potential too low to cause hydrogen evolution. Cyclic voltammetry testing of the positive and negative electrode active materials indicates that they are within the electrochemical window.

[0135] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. A water-in-salt semisolid suspension, characterized in that: The components include solid active material, solid conductive carbon and salt-in-water type electrolyte, the salt-in-water type electrolyte includes electrolyte, water and co-solvent, the concentration of the salt-in-water type electrolyte is ≥10 mol / L, the co-solvent is 1,3-dioxolane, and the volume ratio of water to co-solvent is 1:1~3.

2. water-in-salt type semisolid suspension according to claim 1, is characterized in that, The solid active material includes a positive electrode solid active material or a negative electrode solid active material.

3. water-in-salt type semisolid suspension according to claim 2, is characterized in that, The positive electrode solid active material includes at least one of LiFePO4, LiMn2O4 and LiCoO2.

4. water-in-salt type semisolid suspension according to claim 2, is characterized in that, The negative electrode solid active material includes selenium-carbon composite material, sulfur-carbon composite material, Li4Ti5O 12 and at least one of Mo6S8.

5. The water-in-salt semisolid suspension according to claim 1, wherein The electrolyte includes at least one of LiTFSI, LiOTF, LiFSI, LiCl, LiBF4, LiDFOB, and LiClO4.

6. The water-in-salt semisolid suspension according to any one of claims 1 to 5, characterized in that The volume ratio of water to co-solvent is 1:

1.

7. A method for preparing the water-in-salt semisolid suspension according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) adding the electrolyte to the water and the co-solvent to obtain the water-in-salt electrolyte; (2) Adding the solid active material and solid conductive carbon to the water-in-salt electrolyte, stirring after ultrasonic vibration, to obtain the water-in-salt semi-solid suspension.

8. The method according to claim 7, characterized in that The ultrasonic oscillation time is 5 min to 10 min.

9. The method according to claim 7, characterized in that The stirring time is 20 min to 40 min.

10. A water-in-salt semi-solid suspension flow battery, characterized in that: The invention comprises a battery reaction unit, a liquid storage system, a circulation system, and the water-in-salt semi-solid suspension according to any one of claims 1 to 6.

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