High-voltage aqueous potassium-ion full cell and method of stabilizing prussian blue-based negative electrode material

Abstract

The present application relates to a kind of high-voltage aqueous potassium ion full battery and the method for stabilizing prussian blue type negative material.High-voltage aqueous potassium ion full battery includes: the negative material of prussian blue type compound, positive material and the electrolyte of the aqueous solution of potassium salt added with organic matter additive composition;Electrolyte is the mixed solution of aqueous solution of potassium salt and organic matter additive, the binding energy of organic matter additive and potassium ion is greater than the binding energy of water and potassium ion, and organic matter additive is used to accompany potassium ion to insert, electrode and prevent the crystallization water inside negative electrode from being removed;When high-voltage aqueous potassium ion full battery is charged and discharged, potassium ion with water and / or organic matter additive molecular solvation shell layer is removed and inserted in positive electrode and negative electrode and reacts.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a method for a high-voltage aqueous potassium-ion full cell and a stable Prussian blue anode material. Background Technology

[0002] With the continuous depletion of fossil fuels and the increasingly severe environmental pollution, the development of renewable energy sources such as solar, wind, and tidal energy has become a global issue urgently needing human development. In the process of developing new energy sources, efficient energy storage has become crucial. Among all energy storage systems, electrochemical energy storage has received widespread attention from scholars worldwide due to its flexible application and high conversion efficiency. Especially in recent years, the widespread application and development of lithium-ion batteries and sodium-ion batteries have made new energy batteries increasingly important in the energy storage field. In the field of electrochemical energy storage, lithium-ion batteries have received widespread attention and application due to their high voltage, high capacity, and long cycle life. However, lithium resources are limited and unevenly distributed. As lithium resources are gradually depleted, this shortcoming will inevitably become a key factor restricting its development. Potassium, as a group element of lithium, not only has more abundant reserves and an electrode potential close to that of lithium, but its solvation shell in solution is also smaller than that of lithium ions. In aqueous systems, the ionic conductivity of potassium salt aqueous solutions is higher than that of lithium salt systems, meaning that potassium-based aqueous electrolytes have superior rate performance compared to lithium-based electrolytes. Moreover, from the perspectives of safety performance and cost, aqueous potassium-ion batteries are even more worthy of research.

[0003] Currently, research on aqueous potassium-ion secondary batteries is very limited. Only a very small number of reports exist regarding Prussian blue as the positive electrode in a three-electrode system for aqueous potassium-ion batteries, and reports on full-cell aqueous potassium-ion batteries are even rarer. This is mainly because the available positive and negative electrode materials are too limited in aqueous systems, especially the negative electrode material for aqueous potassium-ion batteries, as most usable materials have electrode potentials that are too low to match the voltage window of potassium-based aqueous electrolytes. To date, no reported full-cell aqueous potassium-ion battery system has a discharge voltage exceeding 1.8V. Summary of the Invention

[0004] This invention provides a method for a high-voltage aqueous potassium-ion full cell and a stable Prussian blue anode material, which has an average discharge voltage higher than 1.8V, high effective energy density, and good cycle performance at low rates.

[0005] In a first aspect, embodiments of the present invention provide a high-voltage aqueous potassium-ion full battery, comprising: a negative electrode material composed of Prussian blue compounds, a positive electrode material, and an electrolyte composed of an aqueous solution of potassium salt with added organic additives.

[0006] The general formula of the Prussian blue compounds constituting the negative electrode material is: N1 x M1[Cr(CN)6] y ·zH2O, where N1 is any one or two of Na and K, M1 is one or more of Mn, Fe, Co, Ni, Cu, Zn, and Cr, 0<x≤1, 0<y≤1, 0<z≤5;

[0007] The electrolyte is a mixed solution composed of potassium salt aqueous solution and organic additive, wherein the potassium salt aqueous solution has a concentration of 1 mol / L-22 mol / L and the concentration of organic additive is less than or equal to 5 mol / L; the binding energy between the organic additive and potassium ions is greater than the binding energy between water and potassium ions, and the organic additive is used to accompany potassium ions in inserting and de-inserting into the electrode and to prevent the crystal water inside the negative electrode from being released.

[0008] When the high-voltage aqueous potassium-ion full battery is charged, potassium ions in the positive electrode material are released into the electrolyte. Each potassium ion in the electrolyte carries a water molecules and b organic additive molecules and embeds them into the negative electrode material, where 0≤a≤6 and 0<b≤2.

[0009] When the high-voltage aqueous potassium-ion full battery is discharged, potassium ions in the negative electrode material carry a water molecules and b organic additive molecules out of the negative electrode material and enter the electrolyte. Potassium ions in the electrolyte carry m water molecules and n organic additive molecules and embed into the positive electrode material, where 0≤m≤6 and 0<n≤2.

[0010] Preferably, the general formula of the Prussian blue-like compound constituting the positive electrode material is: K q M2 h Fe(CN)6·jH2O, where M2 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0<q≤2, 0<h≤1, and 0≤j≤5.

[0011] Preferably, the organic additives include one or more of the following: glyceraldehyde, dihydroxyacetone, erythrose, ribose, deoxyribose, arabinose, xylose, lysolose, idoleose, glucose, fructose, galactose, mannose, rhamnose, sedoheptulose, mannoheptulose, sucrose, lactose, and maltose.

[0012] Preferably, after the high-voltage aqueous potassium-ion full battery is charged, the increased concentration of water of crystallization inside the negative electrode acts as a lubricant to improve the migration rate of potassium ions inside the electrode structure; and suppresses the increased polarization of charge and discharge caused by the release of water of crystallization along with potassium ions during the discharge of the high-voltage aqueous potassium-ion full battery.

[0013] Preferably, the potassium salt in the potassium salt aqueous solution includes one or more of K2SO4, KCl, KNO3, K3PO4, K2HPO4, KH2PO4, CH3COOK, K2C2O4, KClO4, KCF3SO3, F2KNO4S2, C2F6KNO4S2, KF, and KI.

[0014] Secondly, embodiments of the present invention provide a method for stabilizing Prussian blue-based anode materials, the method comprising:

[0015] A high-voltage aqueous potassium-ion full cell is constructed by combining a positive electrode material composed of Prussian blue compounds, a negative electrode material composed of Prussian blue compounds, and an electrolyte composed of potassium salt aqueous solution with added organic additives.

[0016] The electrolyte is a mixed solution composed of potassium salt aqueous solution and organic additives, wherein the potassium salt aqueous solution has a concentration of 1 mol / L-22 mol / L and the concentration of organic additives is less than or equal to 5 mol / L.

[0017] The organic additive binds to potassium ions with greater energy than water binds to potassium ions. The organic additive is used to accompany potassium ions as they insert into and exit the electrode and to prevent the release of crystal water from the inside of the negative electrode.

[0018] Preferably, during the charging of the high-voltage aqueous potassium-ion full battery, potassium ions in the positive electrode material are released into the electrolyte, and each potassium ion in the electrolyte carries a water molecules and b organic additive molecules that are embedded in the negative electrode material, where 0≤a≤6 and 0<b≤2.

[0019] When the high-voltage aqueous potassium-ion full battery is discharged, potassium ions in the negative electrode material carry a water molecules and b organic additive molecules out of the negative electrode material and enter the electrolyte. Potassium ions in the electrolyte carry m water molecules and n organic additive molecules and embed into the positive electrode material, where 0≤m≤6 and 0<n≤2.

[0020] Preferably, the negative electrode material is composed of a Prussian blue compound with the general formula N1. x M1[Cr(CN)6] y ·zH2O, where N1 is any one or two of Na and K, M1 is one or more of Mn, Fe, Co, Ni, Cu, Zn, and Cr, 0<x≤1, 0<y≤1, 0<z≤5;

[0021] The positive electrode material is composed of Prussian blue compounds, with the general formula: K q M2 hFe(CN)6·jH2O, where M2 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0<q≤2, 0<h≤1, and 0≤j≤5;

[0022] The organic additives include one or more of the following: glyceraldehyde, dihydroxyacetone, erythrose, ribose, deoxyribose, arabinose, xylose, lysolose, idoleose, glucose, fructose, galactose, mannose, rhamnose, sedoheptulose, mannoheptulose, sucrose, lactose, and maltose.

[0023] The potassium salt in the potassium salt aqueous solution includes one or more of the following: K2SO4, KCl, KNO3, K3PO4, K2HPO4, KH2PO4, CH3COOK, K2C2O4, KClO4, KCF3SO3, F2KNO4S2, C2F6KNO4S2, KF, and KI.

[0024] Thirdly, embodiments of the present invention provide an application of the high-voltage aqueous potassium-ion full battery described in the first aspect above, wherein the high-voltage aqueous potassium-ion full battery is used as a mobile power source for electric vehicles and portable devices, as well as a large-scale energy storage device for solar power generation, smart grid peak shaving, large power plants or communication base stations.

[0025] The high-voltage aqueous potassium-ion full battery proposed in this invention is an aqueous potassium-ion full battery with an average discharge voltage higher than 1.8V, high effective energy density, and good cycle performance at low rates, constructed by using a positive electrode material composed of Prussian blue compounds, a negative electrode material composed of Prussian blue compounds, and an electrolyte composed of an aqueous solution of potassium salt with added organic additives. This novel aqueous potassium-ion full battery has a simple, green, safe, and low-cost manufacturing process and is currently the aqueous potassium-ion battery system with the highest effective energy density. This battery can be applied in large-scale energy storage power stations, portable power sources for mobile devices, electric vehicles, and hybrid electric vehicles, serving as a power source for electric vehicles and portable devices, as well as a large-scale energy storage device for solar power generation, smart grid peak shaving, large power stations, or communication base stations. Attached Figure Description

[0026] The technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0027] Figure 1 The positive electrode material K used in Embodiment 1 and Comparative Example 1 of this invention 1.8 Mn 0.8 Fe 0.2 X-ray diffraction (XRD) pattern of Fe(CN)6·H2O;

[0028] Figure 2K is the negative electrode material used in Embodiment 1 and Comparative Example 1 of the present invention. 0.01 Mn[Cr(CN)6] 0.74 XRD pattern of 4H2O;

[0029] Figure 3 K is the comparative example 1 of this invention. 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of a three-electrode battery with a working electrode of 4H2O, a reference electrode of (Ag / AgCl), and an activated carbon counter electrode, in the voltage range of -1.2V to 0V at a current density of 300mA / g, with 21mol / L KCF3SO3 as the electrolyte;

[0030] Figure 4 K is the comparative example 1 of this invention. 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / 21mol / L KCF3SO3 / K 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of the 4H2O full cell at a low current of 100mA / g;

[0031] Figure 5 K is the embodiment of the present invention. 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of a three-electrode battery with a working electrode of 4H2O, a reference electrode of (Ag / AgCl), and an activated carbon counter electrode, in the voltage range of -1.2V to 0V at a current density of 300mA / g, with an electrolyte of 21mol / L KCF3SO3+1mol / L;

[0032] Figure 6 K is the embodiment of the present invention. 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / 21mol / L KCF3SO3+1mol / L / K 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of the 4H2O full cell at a low current of 100mA / g. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any way, that is, not intended to limit the scope of protection of the present invention.

[0034] The high-voltage aqueous potassium-ion full battery proposed in this invention comprises a positive electrode material composed of Prussian blue compounds, a negative electrode material composed of Prussian blue compounds, and an electrolyte composed of a potassium salt aqueous solution with added organic additives.

[0035] The general formula for Prussian blue compounds constituting the cathode material is: K q M2 h Fe(CN)6·jH2O, where M2 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0<q≤2, 0<h≤1, and 0≤j≤5;

[0036] The general formula for Prussian blue compounds constituting the negative electrode material is: N1 x M1[Cr(CN)6] y ·zH2O, where N1 is any one or two of Na and K, M1 is one or more of Mn, Fe, Co, Ni, Cu, Zn, and Cr, 0<x≤1, 0<y≤1, 0<z≤5;

[0037] In a preferred embodiment, the positive and negative electrodes further include appropriate amounts of conductive agent and binder, respectively. The electrolyte is a mixed solution composed of potassium salt aqueous solution and organic additives, wherein the potassium salt aqueous solution is 1 mol / L-22 mol / L. Within this range, the higher the concentration of the electrolyte, the lower the electrolyte content required in the final actual battery, the higher the energy density, and the better the battery performance at low rates. The concentration of organic additives is less than or equal to 5 mol / L; the potassium salts in the potassium salt aqueous solution include one or more of the following: K2SO4, KCl, KNO3, K3PO4, K2HPO4, KH2PO4, CH3COOK, K2C2O4, KClO4, KCF3SO3, F2KNO4S2, C2F6KNO4S2, KF, and KI; the organic additives include one or more of the following: glyceraldehyde, dihydroxyacetone, erythrose, ribose, deoxyribose, arabinose, xylose, lythose, idose, glucose, fructose, galactose, mannose, rhamnose, sedoheptulose, mannoheptulose, sucrose, lactose, and maltose.

[0038] The binding energy between organic additives and potassium ions is greater than that between water and potassium ions. Organic additives are used to accompany potassium ions in insertion and extraction from the electrode and to prevent the crystal water inside the negative electrode from being extracted.

[0039] The working principle of the high-voltage aqueous potassium-ion full battery of the present invention can be summarized as: the intercalation and deintercalation reaction of potassium ions with a solvation shell of water and / or organic additive molecules in the positive and negative electrodes.

[0040] When a high-voltage aqueous potassium-ion full battery is charged, potassium ions are released from the positive electrode material and enter the electrolyte. Each potassium ion in the electrolyte carries a water molecules and b organic additive molecules and embeds into the negative electrode material, where 0≤a≤6 and 0<b≤2.

[0041] When a high-voltage aqueous potassium-ion full cell discharges, potassium ions in the negative electrode material carry a water molecules and b organic additive molecules out of the negative electrode material and enter the electrolyte. Potassium ions in the electrolyte carry m water molecules and n organic additive molecules and embed into the positive electrode material, where 0≤m≤6 and 0<n≤2.

[0042] This invention constructs a high-voltage aqueous potassium-ion full battery by combining a positive electrode material composed of Prussian blue-like compounds, a negative electrode material composed of Prussian blue-like compounds, and an electrolyte composed of an aqueous solution of potassium salt with added organic additives. It utilizes the fact that the binding energy between organic additives and potassium ions is greater than that between water and potassium ions. The intercalation and deintercalation reaction of potassium ions with water or organic additive molecules generated by the aqueous solution of potassium salt with added organic additives in the positive and negative electrodes prevents the release of crystal water from the inside of the negative electrode, thus stabilizing the Prussian blue-like negative electrode material.

[0043] The preparation process of the high-voltage aqueous potassium-ion full battery of the present invention will be described below.

[0044] Taking a specific process as an example, the preparation of the positive / negative electrodes and K in this invention q M2 h Fe(CN)6·jH2O-N1 x M1[Cr(CN)6] y The general steps for assembling a zH2O system full cell are as follows:

[0045] 1) K q M2 h Preparation of Fe(CN)6·jH2O cathode

[0046] An aqueous solution of chloride M₂Cl₂ is prepared and added dropwise to an aqueous solution of K₄Fe(CN)₆. The mixture is stirred for 1-24 hours. The resulting precipitate is washed by centrifugation and then dried under vacuum to prepare K₂Cl₆. q M2 h Fe(CN)6·jH2O cathode material.

[0047] 2) N1 x M1[Cr(CN)6] y Preparation of zH2O negative electrode

[0048] An aqueous solution of chloride M1Cl2 is prepared and added dropwise to an aqueous solution of N13Cr(CN)6. The mixture is stirred and reacted for 1-24 hours. The resulting precipitate is then centrifuged, washed, and vacuum dried to prepare N1. x M1[Cr(CN)6] y • zH2O cathode material.

[0049] 3) Prepare electrolyte by adding organic additives to potassium salt aqueous solution.

[0050] For example: an electrolyte consisting of 1 ml of saturated KCF3SO3 aqueous solution and 1 mol / L glucose solution.

[0051] 4) Assembly of the full battery

[0052] The cathode material uses K q M2 h Fe(CN)6·jH2O, the negative electrode material uses N1 x M1[Cr(CN)6] y ·zH2O, grind them separately with conductive agent and binder until uniform, add appropriate amount of alcohol, and roll and press into self-supporting positive and negative electrode sheets. Use glass fiber as separator, add prepared electrolyte, and assemble into a full cell.

[0053] The high-voltage aqueous potassium-ion full battery provided in this invention uses Prussian blue compounds as negative and positive electrode materials to construct a novel aqueous potassium-ion full battery with high voltage, high effective energy density, and good low-rate cycle stability.

[0054] The high-voltage aqueous potassium-ion full battery of the present invention uses a mixed aqueous solution of potassium salt and organic additives as electrolyte. During the charging and discharging process, the water of crystallization inside the negative electrode will be released along with the potassium ions, causing the polarization to increase during subsequent charging and discharging. The addition of additives can preferentially combine with potassium ions before water molecules, and can also prevent the water of crystallization inside the electrode from being released along with potassium ions during subsequent charging and discharging, thereby suppressing the increase in charging and discharging polarization caused by the release of water of crystallization along with potassium ions during the discharge of the high-voltage aqueous potassium-ion full battery.

[0055] The novel high-voltage aqueous potassium-ion full battery proposed in this invention features a simple, environmentally friendly, and low-cost fabrication process with minimal environmental requirements, making it an excellent electrochemical energy storage system. It can be applied to large-scale energy storage power stations, portable power supplies for mobile devices, and electric vehicles.

[0056] To better understand the technical solution provided by this invention, the following description, in conjunction with specific embodiments and comparative examples, illustrates the strategy for stabilizing Prussian blue anode materials proposed in this invention and the development and application of high-voltage aqueous potassium-ion full cells.

[0057] Comparative Example 1

[0058] This comparative example uses K. 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / K 0.01 Mn[Cr(CN)6] 0.74 The assembly and performance of the 4H2O system full cell are explained.

[0059] The mass ratio of the positive to negative electrodes is 1:2. The electrolyte is a 21 mol / L KCF3SO3 aqueous solution.

[0060] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O (same as Example 1), the negative electrode material is K 0.01 Mn[Cr(CN)6] 0.74 • 4H2O (same as in Example 1) was mixed evenly according to the weight ratio of active material: carbon nanotubes: polytetrafluoroethylene (PTFE) binder = 7:2:1. An appropriate amount of alcohol was added, and the mixture was rolled and pressed into self-supporting positive and negative electrode sheets. After drying, these became the positive and negative electrodes. Glass fiber was used as the separator, and 21 mol / L KCF3SO3 aqueous solution was used as the electrolyte to assemble a full battery.

[0061] Figure 1 Demonstrating the cathode material K 1.8 Mn 0.8 Fe 0.2 The XRD pattern of Fe(CN)6·H2O shows that the cathode material has a typical Prussian blue structure.

[0062] Figure 2 The negative electrode material K was demonstrated. 0.01 Mn[Cr(CN)6] 0.74 The XRD pattern of 4H2O shows that the anode material has a typical Prussian blue structure.

[0063] Figure 3 Showing K 0.01 Mn[Cr(CN)6] 0.74The charge-discharge curves of a three-electrode battery with 4H₂O as the working electrode, Ag / AgCl as the reference electrode, and activated carbon as the counter electrode, and with the aforementioned electrolyte added, are shown at a current density of 300 mA / g and a voltage range of -1.2V to 0V. Its reversible capacity in the first cycle is 67 mAh / g, the efficiency in the first cycle is 86%, and the average charging voltage is -1.0V (vs. Ag / AgCl). Notably, starting from the third charge cycle, a new charging plateau appears around -0.8V, and the high-potential plateau continuously lengthens with further charge and discharge, indicating increased polarization.

[0064] Figure 4 For K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / 21mol / L KCF3SO3 / K 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of the 4H₂O full cell at a low current of 100 mA / g. As charge and discharge proceed, the discharge plateau of the full cell continuously decreases, leading to a sustained reduction in the battery's energy density. This is due to potassium ions being released from the negative electrode during discharge, continuously carrying away water of crystallization.

[0065] Example 1

[0066] K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / K 0.01 Mn[Cr(CN)6] 0.74 Assembly and performance of a 4H₂O system full cell, with a positive to negative electrode mass ratio of 1:2. The electrolyte was a 21 mol / L KCF₃SO₃ + 1 mol / L glucose aqueous solution.

[0067] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O, the negative electrode material uses K 0.01 Mn[Cr(CN)6] 0.74 • 4H2O, all are mixed evenly according to the weight ratio of active material: carbon nanotubes: PTFE binder = 7:2:1, an appropriate amount of alcohol is added, and the mixture is rolled and pressed into a self-supporting electrode sheet. After drying, it becomes the positive and negative electrodes. Glass fiber is used as the separator, and an aqueous solution of 21mol / L KCF3SO3 + 1mol / L glucose is used as the electrolyte to assemble a full cell.

[0068] Figure 5 K was shown 0.01Mn[Cr(CN)6] 0.74 The charge-discharge curves of a three-electrode battery with a 4H₂O working electrode, Ag / AgCl as the reference electrode, and activated carbon as the counter electrode, and with the aforementioned electrolyte added, are shown at a current density of 300 mA / g and a voltage range of -1.2V to 0V. Its first-week reversible capacity is 67 mAh / g, the first-week efficiency is 85%, and the average charging voltage is -1.0V (vs. Ag / AgCl). Notably, throughout the charge-discharge process, this half-cell system consistently exhibits only a -1.0V (vs. Ag / AgCl) charging plateau.

[0069] Figure 6 For K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / 21mol / L KCF3SO3+1mol / L glucose aqueous solution / K 0.01 Mn[Cr(CN)6] 0.74 • Charge-discharge curves of the 4H₂O full cell at a low current of 100 mA / g. As charge and discharge proceed, the discharge plateau of the full cell does not show a significant decrease. This is because the additive molecules encapsulate potassium ions, inhibiting further binding of water molecules with potassium ions, and thus also inhibiting the release of water molecules from the electrode along with potassium ions. This effectively solves the polarization increase problem involved in Comparative Example 1.

[0070] Example 2

[0071] K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / K 0.01 Fe[Cr(CN)6] 0.74 Assembly and performance of a 4H₂O system full cell, with a positive to negative electrode mass ratio of 1:2. The electrolyte was a 21 mol / L KCF₃SO₃ + 1 mol / L glucose aqueous solution.

[0072] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O, the negative electrode material uses K 0.01 Fe[Cr(CN)6] 0.74 • 4H2O, all are mixed evenly according to the weight ratio of active material: carbon nanotubes: PTFE binder = 7:2:1, an appropriate amount of alcohol is added, and the mixture is rolled and pressed into a self-supporting electrode sheet. After drying, it becomes the positive and negative electrodes. Glass fiber is used as the separator, and an aqueous solution of 21mol / L KCF3SO3 + 1mol / L glucose is used as the electrolyte to assemble a full cell.

[0073] Example 3

[0074] K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / K 0.01 Zn[Cr(CN)6] 0.74 Assembly and performance of a 4H₂O system full cell, with a positive to negative electrode mass ratio of 1:2. The electrolyte was a 21 mol / L KCF₃SO₃ + 1 mol / L glucose aqueous solution.

[0075] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O, the negative electrode material uses K 0.01 Zn[Cr(CN)6] 0.74 • 4H2O, all are mixed evenly according to the weight ratio of active material: carbon nanotubes: PTFE binder = 7:2:1, an appropriate amount of alcohol is added, and the mixture is rolled and pressed into a self-supporting electrode sheet. After drying, it becomes the positive and negative electrodes. Glass fiber is used as the separator, and an aqueous solution of 21mol / L KCF3SO3 + 1mol / L glucose is used as the electrolyte to assemble a full cell.

[0076] Example 4

[0077] K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / K 0.01 Mn[Cr(CN)6] 0.74 Assembly and performance of a 4H₂O system full cell, with a positive to negative electrode mass ratio of 1:2. The electrolyte was a 21 mol / L KCF₃SO₃ + 1 mol / L fructose aqueous solution.

[0078] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O, the negative electrode material uses K 0.01 Mn[Cr(CN)6] 0.74 • 4H2O, all are mixed evenly according to the weight ratio of active material: carbon nanotube: PTFE binder = 7:2:1, an appropriate amount of alcohol is added, and the mixture is rolled and pressed into a self-supporting electrode sheet. After drying, it becomes the positive and negative electrodes. Glass fiber is used as the separator, and an aqueous solution of 21mol / L KCF3SO3 + 1mol / L fructose is used as the electrolyte to assemble a full cell.

[0079] Example 5

[0080] K 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O / Na 0.01 Mn[Cr(CN)6] 0.74 Assembly and performance of a 4H₂O system full cell, with a positive to negative electrode mass ratio of 1:2. The electrolyte was a 21 mol / L KCF₃SO₃ + 1 mol / L sucrose aqueous solution.

[0081] The positive and negative electrode materials were prepared according to the general steps of full cell assembly. The positive electrode material used was K... 1.8 Mn 0.8 Fe 0.2 Fe(CN)6·H2O, the negative electrode material is Na 0.01 Mn[Cr(CN)6] 0.74 The active material, carbon nanotubes, and PTFE binder were mixed evenly in a weight ratio of 7:2:1. An appropriate amount of alcohol was added, and the mixture was rolled and pressed into self-supporting electrode sheets. After drying, these became the positive and negative electrodes. A glass fiber separator was used as the membrane, and a 21 mol / L KCF3SO3 + 1 mol / L sucrose aqueous solution was used as the electrolyte to assemble a full battery.

[0082] The high-voltage aqueous potassium-ion full battery provided in this invention uses potassium-based Prussian blue compounds as both the negative and positive electrode materials. The average charging voltage of the negative electrode is the lowest among currently used materials in this system. A mixed solution of potassium salt aqueous solution and organic additives is used as the electrolyte. The combination of the additives and potassium ions can suppress the increased polarization caused by the release of water of crystallization within the electrodes during charging and discharging. This invention constructs a novel aqueous potassium-ion full battery with high voltage, high effective energy density, and excellent low-rate cycling stability. This novel high-voltage aqueous potassium-ion full battery is not only simple to synthesize and easy to assemble, but also green, clean, safe, and environmentally friendly. It is an excellent electrochemical energy storage system that can be applied to large-scale energy storage power stations, portable power supplies for mobile devices, electric vehicles, and other fields.

[0083] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-voltage aqueous potassium-ion full battery, characterized in that, The high-voltage aqueous potassium-ion full battery comprises: a negative electrode material composed of Prussian blue compounds, a positive electrode material composed of Prussian blue compounds, and an electrolyte composed of an aqueous solution of potassium salt with added organic additives. The general formula of the Prussian blue compounds constituting the negative electrode material is: N1 x M1[Cr(CN)6] y •zH2O, where N1 is any one or two of Na and K, M1 is one or more of Mn, Fe, Co, Ni, Cu, Zn, and Cr, 0 < x ≤ 1, 0 < y ≤ 1, and 0 < z ≤ 5; The electrolyte is a mixed solution composed of potassium salt aqueous solution and organic additive, wherein the potassium salt aqueous solution has a concentration of 1 mol / L-22 mol / L and the concentration of organic additive is less than or equal to 5 mol / L; the binding energy between the organic additive and potassium ions is greater than the binding energy between water and potassium ions, and the organic additive is used to accompany potassium ions in inserting and de-inserting into the electrode and to prevent the crystal water inside the negative electrode from being released. When the high-voltage aqueous potassium-ion full battery is charged, potassium ions in the positive electrode material are released into the electrolyte. Each potassium ion in the electrolyte carries a water molecules and b organic additive molecules and embeds them into the negative electrode material, where 0≤a≤6 and 0<b≤2. When the high-voltage aqueous potassium-ion full battery is discharged, potassium ions in the negative electrode material carry a water molecules and b organic additive molecules out of the negative electrode material and enter the electrolyte. Potassium ions in the electrolyte carry m water molecules and n organic additive molecules and embed into the positive electrode material, where 0≤m≤6 and 0<n≤2.

2. The high-voltage aqueous potassium-ion full battery according to claim 1, characterized in that, The general formula of the Prussian blue compounds constituting the cathode material is: K q M2 h Fe(CN)6•jH2O, where M2 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0<q≤2, 0<h≤1, and 0≤j≤5.

3. The high-voltage aqueous potassium-ion full battery according to claim 1, characterized in that, Organic additives include one or more of the following: glyceraldehyde, dihydroxyacetone, erythrose, ribose, deoxyribose, arabinose, xylose, lysolose, idoleose, glucose, fructose, galactose, mannose, rhamnose, sedoheptulose, mannoheptulose, sucrose, lactose, and maltose.

4. The high-voltage aqueous potassium-ion full battery according to claim 1, characterized in that, After the high-voltage aqueous potassium-ion full battery is charged, the increased concentration of water of crystallization inside the negative electrode acts as a lubricant to improve the migration rate of potassium ions inside the electrode structure; and suppresses the increased polarization of charge and discharge caused by the release of water of crystallization along with potassium ions during the discharge of the high-voltage aqueous potassium-ion full battery.

5. The high-voltage aqueous potassium-ion full battery according to claim 1, characterized in that, The potassium salt in the potassium salt aqueous solution includes one or more of the following: K2SO4, KCl, KNO3, K3PO4, K2HPO4, KH2PO4, CH3COOK, K2C2O4, KClO4, KCF3SO3, F2KNO4S2, C2F6KNO4S2, KF, and KI.

6. A method for stabilizing Prussian blue-based anode materials, characterized in that, The method includes: constructing a high-voltage aqueous potassium-ion full battery by combining a positive electrode material composed of Prussian blue compounds, a negative electrode material composed of Prussian blue compounds, and an electrolyte composed of an aqueous solution of potassium salt with added organic additives. The electrolyte is a mixed solution composed of potassium salt aqueous solution and organic additives, wherein the potassium salt aqueous solution has a concentration of 1 mol / L-22 mol / L and the concentration of organic additives is less than or equal to 5 mol / L. The organic additive binds to potassium ions with greater energy than water binds to potassium ions. The organic additive is used to accompany potassium ions as they insert into and exit the electrode and to prevent the release of crystal water from the inside of the negative electrode.

7. The method according to claim 6, characterized in that, When the high-voltage aqueous potassium-ion full battery is charged, potassium ions in the positive electrode material are released into the electrolyte. Each potassium ion in the electrolyte carries a water molecules and b organic additive molecules and embeds them into the negative electrode material, where 0≤a≤6 and 0<b≤2. When the high-voltage aqueous potassium-ion full battery is discharged, potassium ions in the negative electrode material carry a water molecules and b organic additive molecules out of the negative electrode material and enter the electrolyte. Potassium ions in the electrolyte carry m water molecules and n organic additive molecules and embed into the positive electrode material, where 0≤m≤6 and 0<n≤2.

8. The method according to claim 7, characterized in that, The negative electrode material is composed of Prussian blue compounds, with the general formula: N1 x M1[Cr(CN)6] y •zH2O, where N1 is any one or two of Na and K, M1 is one or more of Mn, Fe, Co, Ni, Cu, Zn, and Cr, 0 < x ≤ 1, 0 < y ≤ 1, and 0 < z ≤ 5; The positive electrode material is composed of Prussian blue compounds, with the general formula: K q M2 h Fe(CN)6•jH2O, where M2 is one or more of Mn, Fe, Co, Ni, Cu, and Zn, 0<q≤2, 0<h≤1, and 0≤j≤5; The organic additives include one or more of the following: glyceraldehyde, dihydroxyacetone, erythrose, ribose, deoxyribose, arabinose, xylose, lysolose, idoleose, glucose, fructose, galactose, mannose, rhamnose, sedoheptulose, mannoheptulose, sucrose, lactose, and maltose. The potassium salt in the potassium salt aqueous solution includes one or more of the following: K2SO4, KCl, KNO3, K3PO4, K2HPO4, KH2PO4, CH3COOK, K2C2O4, KClO4, KCF3SO3, F2KNO4S2, C2F6KNO4S2, KF, and KI.

9. The use of a high-voltage aqueous potassium-ion full battery according to any one of claims 1-5, characterized in that, The high-voltage aqueous potassium-ion full battery is used as a mobile power source for electric vehicles and portable devices, as well as a large-scale energy storage device for solar power generation, smart grid peak shaving, large power plants, or communication base stations.

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