A molten salt aluminum displacement battery based on transition metal chlorination reaction and a preparation method thereof

Abstract

The present application relates to the technical field of stationary electrochemical energy storage secondary aluminum battery, and particularly relates to a molten salt aluminum displacement battery based on transition metal chlorination reaction and a preparation method thereof. The membrane-free aluminum displacement battery based on transition metal chlorination reaction in molten salt comprises a positive electrode, a negative electrode, a diaphragm between the positive electrode and the negative electrode and an alkaline molten salt electrolyte; the positive electrode comprises a positive electrode current collector and a positive electrode material, the positive electrode material comprises a positive electrode active material, the positive electrode active material comprises a transition metal and / or a chloride of a transition metal element; the negative electrode comprises metal aluminum and / or an aluminum alloy, and the metal aluminum or the aluminum alloy can simultaneously serve as a negative electrode current collector and a negative electrode active material; the alkaline molten salt electrolyte is made of an electrolyte aluminum salt and an alkali metal chlorinated salt. The battery does not need the beta ''-Al2O3 membrane in the ZEBRA battery, has high capacity, fast charging and discharging, ultra-low cost and long cycle life, and is suitable for a new type of secondary aluminum battery stationary energy storage system of a power grid.

Description

Technical Field

[0001] This invention relates to the field of stationary electrochemical energy storage secondary aluminum battery technology, specifically to a molten salt aluminum displacement battery based on transition metal chlorination reaction and its preparation method. Background Technology

[0002] With the rapid development of renewable energy, the demand for low-cost, high-safety, and long-life battery technologies for stationary energy storage systems is becoming increasingly urgent. Current mainstream lithium-ion batteries are limited by the scarcity of lithium resources, the risk of thermal runaway, and high cost, making it difficult to meet the demands of grid-scale energy storage. Therefore, there is an urgent need to develop a new generation of battery systems that are intrinsically safe, low-cost, and abundant in resources for stationary electrochemical energy storage. Against this backdrop, sodium-nickel chloride (ZEBRA) batteries and aluminum-based batteries have attracted widespread attention due to their abundant materials and high safety, but significant technological bottlenecks still exist.

[0003] Existing ZEBRA batteries are based on a substitution reaction between Na and NiCl2, using a β”-Al2O3 membrane to separate the liquid sodium anode and the molten salt cathode (NaCl-AlCl3). Although their energy density can reach 120Wh / kg, the β”-Al2O3 membrane is susceptible to chemical corrosion by the molten salt during long-term operation, leading to membrane rupture, decreased ionic conductivity, and short circuits. Furthermore, high-temperature operation (270-350℃) accelerates the aging of sealing materials, further increasing maintenance costs. In addition, aluminum metal batteries, due to their high volumetric capacity (8046mAh / cm³),... 3 The abundance of the cathode material (8.3 wt%) and its intrinsic high safety are considered ideal choices; however, they are limited by the low capacity of the cathode material (e.g., graphite <200 mAh / g) and the slow reaction kinetics (Al). 3+ High diffusion barriers and the cost and poor electrode compatibility of traditional electrolyte systems still pose challenges to the development of large-scale energy storage.

[0004] In view of this, the present invention proposes a membrane-free aluminum displacement battery based on reversible chlorination / dechlorination of transition metals (TM: Ni, Fe, Co) in an alkaline molten salt electrolyte, which successfully solves the above problems and provides an efficient, low-cost and long-life solution for stationary energy storage, with ideal industrialization prospects.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, this invention provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt. It uses metallic aluminum or aluminum alloys as the negative electrode, transition metal and / or transition metal chlorides (TMCs) as the positive electrode, and employs a molten salt electrolyte composed of aluminum salt and alkali metal chloride (ACl). By controlling the Lewis acidity / alkalinity of the molten salt electrolyte, a solution with AlCl4 is formed. - The predominantly cluster-structured alkaline molten salt electrolyte inhibits the dissolution of chloride at the positive electrode, enabling a reversible solid-solid reaction. This battery does not require the β”-Al2O3 film found in ZEBRA batteries and features intrinsically high safety, high capacity (>350mAh / g), fast charge and discharge (capacity retention >30% at 5A / g), ultra-low cost (Al-Fe battery material cost <8 USD / kWh), and long cycle life (capacity retention >83% after 500 cycles). It is suitable for grid-scale stationary energy storage systems and has good prospects for industrialization.

[0007] The membrane-free aluminum replacement battery provided by this invention has an operating temperature that is much lower than that of current liquid metal batteries based on molten salt (>450℃) and also lower than that of conventional Zebra batteries based on molten salt (>270℃). At a lower operating temperature (90-200℃), the sealing corrosion problem and the problem of excessive energy consumption during heating start-up of molten salt aluminum batteries are solved, and the battery packaging cost and thermal management cost are also significantly reduced.

[0008] Furthermore, this invention provides a method for preparing a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt. The battery operates at a low temperature, significantly reducing the costs of battery packaging and thermal management. The membrane-free aluminum displacement battery based on the chlorination of transition metals in alkaline molten salt enables a reversible solid-solid dual-electron displacement reaction, is intrinsically safe, has high capacity, fast charging, and low cost, making it suitable for applications such as grid-scale stationary energy storage systems.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] This invention provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, comprising a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an alkaline molten salt electrolyte;

[0011] The positive electrode includes a positive electrode current collector and a positive electrode material. The positive electrode current collector includes titanium foil and / or molybdenum foil. The positive electrode material includes a positive electrode active material, which includes a transition metal and / or a chloride of a transition metal element.

[0012] The negative electrode comprises metallic aluminum and / or an aluminum alloy, wherein the metallic aluminum or the aluminum alloy can simultaneously serve as the negative electrode current collector and the negative electrode active material.

[0013] The alkaline molten salt electrolyte is made from an electrolyte aluminum salt and an alkali metal chloride salt.

[0014] According to the above scheme, the positive electrode active material includes one or more of Ni, Fe, Co, NiCl2, FeCl2 and CoCl2.

[0015] According to the above scheme, the diaphragm includes one or more of glass fiber diaphragms, polytetrafluoroethylene diaphragms, and filter paper.

[0016] According to the above scheme, the general formula of the alkaline molten salt electrolyte is AAl. a X b Wherein, A is selected from at least two of Ca, Mg, Li, Na, K, Rb and Cs, and X includes at least one halogen element, 0.8≤a≤1, 3.4≤b≤4, 3a+1≤b.

[0017] According to the above scheme, the halogen elements include one or more of the elements F, Cl, Br and I.

[0018] Preferably, 0.83≤a≤0.95, 3.55≤b≤3.85.

[0019] According to the above scheme, the alkaline molten salt electrolyte is liquid during battery operation and wets the positive electrode, the separator, and the negative electrode.

[0020] According to the above scheme, the operating temperature of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt is ≤300℃;

[0021] Preferably, the operating temperature of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt is 90–200°C.

[0022] The present invention also provides a method for preparing the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, comprising the following steps:

[0023] A positive electrode active material, a positive electrode current collector, a negative electrode, and a separator are obtained. The positive electrode is then obtained by mixing the positive electrode active material, a conductive agent, and a binder and pressing them together.

[0024] And / or, obtain a positive electrode active material, and then dry roll-coat the surface of the current collector after mixing the positive electrode active material, conductive agent and binder to obtain a positive electrode, and then assemble it.

[0025] According to the above scheme, the assembly method is as follows:

[0026] In an inert gas atmosphere, the positive electrode is brought into contact with one side of the separator, and the other side of the separator is brought into contact with the negative electrode. Powdered alkaline molten salt electrolyte is added to the battery structure and heated to a temperature exceeding the melting point of the alkaline molten salt electrolyte to melt the alkaline molten salt electrolyte and wet the positive electrode, the negative electrode, and the separator.

[0027] The cells are then encapsulated to obtain the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The membrane-free aluminum replacement battery based on the chlorination reaction of transition metals in molten salt provided by the present invention can achieve the operation of the battery without β”-Al2O3 membrane by controlling the Lewis acidity of alkaline molten salt electrolyte and limiting the solubility of TMC and its crosstalk with the negative electrode.

[0030] (2) The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt provided by the present invention has a highly reversible solid-solid dual-electron displacement reaction between TMs and TMCs on the positive electrode, and has fast charging characteristics.

[0031] (3) The membrane-free aluminum replacement battery based on the chlorination reaction of transition metals in molten salt provided by the present invention has advantages such as high intrinsic safety, high capacity, low cost and long life. It is suitable for grid-level stationary energy storage systems and has good industrialization prospects. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 Electrochemical reaction mechanism diagram of a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, provided by the present invention;

[0034] Figure 2 The image shows the XRD pattern of the Ni-C cathode active material in Example 1.

[0035] Figure 3 This is a typical snapshot of the AMID trajectories of the two molten salt electrolytes in Example 1, as well as a quantified percentage graph of different Al-Cl clusters.

[0036] Figure 4The Raman spectra of the two molten salt electrolytes in Example 1 are shown.

[0037] Figure 5 The results of ICP-AES measurements are as follows: In Example 1, after adding excess NiCl2 to the two molten salt electrolytes, the results are as follows.

[0038] Figure 6 Typical charge-discharge curves for different molten salt aluminum displacement batteries in Examples 1, 3, and 4;

[0039] Figure 7 The cycling performance of the molten salt aluminum displacement battery in Example 1 at a current density of 0.2 A / g is shown.

[0040] Figure 8 The voltage distribution diagram of the molten salt aluminum replacement battery in Example 1 is shown when the limited discharge capacity is 500 mAh / g, the discharge rate is 0.2 A / g, and the charging rate is 0.2 to 5 A / g.

[0041] Figure 9 The images show the non-in-situ Ni 2p XPS spectra of the Ni-C cathode in the molten salt aluminum replacement battery in Example 1 under different battery charge and discharge states.

[0042] Figure 10 The images shown are TEM and FFT images of the Ni-C cathode in the molten salt aluminum replacement battery in Example 1 under a fully charged state.

[0043] Figure 11 The long-cycle performance of the molten salt aluminum displacement battery in Example 2 at a discharge rate of 0.2 A / g and a high charge rate of 1 A / g is shown.

[0044] Figure 12 This document compares the costs of molten salt aluminum replacement batteries in Examples 1 (Al-Ni represents Example 1) and 3 (Al-Fe represents Example 3) with some mainstream battery systems.

[0045] Figure 13 The first-cycle charging curve of the acidic molten salt aluminum battery in Comparative Example 1 is shown. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0047] It should be noted that, in the description of the embodiments of this application, the term "some specific embodiments" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or instance. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] The phrase "within the range" as used in this invention includes the values ​​at both ends, such as "within the range of 1 to 100" including the values ​​at both ends of 1 and 100.

[0049] In a first aspect, the present invention provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, comprising a positive electrode, a negative electrode, a separator and an alkaline molten salt electrolyte between the positive electrode and the negative electrode.

[0050] The positive electrode includes a positive current collector and a positive electrode material, wherein the positive current collector includes titanium foil and / or molybdenum foil, and the positive electrode material includes a positive active material, which includes a transition metal (TM) and / or a chloride of a transition metal element (TMC).

[0051] In some specific implementations, the transition metal includes one or more of the following: Ni, Fe, and Co.

[0052] In some specific embodiments, the transition metal element includes one or more of Ni, Fe, and Co. That is, the chloride of the transition metal element includes one or more of NiCl2, FeCl2, and CoCl2.

[0053] The negative electrode comprises metallic aluminum and / or an aluminum alloy. Either metallic aluminum or the aluminum alloy can simultaneously serve as the negative electrode current collector and the negative electrode active material.

[0054] The alkaline molten salt electrolyte is made from an electrolyte aluminum salt and an alkali metal chloride salt.

[0055] In some specific embodiments, the electrolyte aluminum salt includes AlCl3, AlBr3, and AlI3.

[0056] In some specific embodiments, the molar ratio of the electrolyte aluminum salt to the alkali metal chloride is 0.8 to 1.0, for example, 0.8, 0.85, 0.9, 0.95, or 1.0. This allows for the control of the Lewis acidity / alkalinity of the alkaline molten salt electrolyte.

[0057] In some specific embodiments, the alkali metal elements in the alkali metal chloride salt include at least two of Ca, Mg, Li, Na, K, Rb, and Cs.

[0058] The membrane-free aluminum displacement battery provided by this invention, based on the chlorination reaction of transition metals in molten salt, exhibits a highly reversible solid-solid two-electron displacement reaction between TMs and their chlorides (TMCs) at the positive electrode, resulting in fast charging characteristics. Importantly, by controlling the Lewis acidity / alkalinity of the molten salt electrolyte and limiting the solubility of TMCs and their crosstalk with the negative electrode, the battery can operate without a β”-Al2O3 membrane.

[0059] In some specific embodiments, the positive electrode active material includes one or more of Ni, Fe, Co, NiCl2, FeCl2, and CoCl2.

[0060] In some specific embodiments, the negative electrode comprises one or more of commercial aluminum foil and / or commercial aluminum alloy foil.

[0061] In some specific embodiments, the diaphragm includes one or more of glass fiber diaphragms, polytetrafluoroethylene diaphragms, and filter paper.

[0062] In some specific embodiments, the general formula of the alkaline molten salt electrolyte is AAl. a X b Wherein, A is selected from at least two of Ca, Mg, Li, Na, K, Rb, and Cs, and X includes at least one halogen element, 0.8≤a≤1, 3.4≤b≤4, and 3a+1≤b. Wherein, a can be, for example, 0.8, 0.85, 0.9, 0.95, or 1, and b can be, for example, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.

[0063] The Lewis acidity or alkalinity of alkaline molten salt electrolytes can be controlled by adjusting the ratio of acidic aluminum salts to basic alkali metal salts.

[0064] In some specific embodiments, the halogen elements include one or more of the elements F, Cl, Br and I.

[0065] In some specific implementations, 0.83 ≤ a ≤ 0.95, 3.55 ≤ b ≤ 3.85. This allows the aluminum-displacement battery to operate at a temperature of 90–160°C.

[0066] In some specific embodiments, the alkaline molten salt electrolyte is liquid during battery operation and wets the positive electrode, the separator, and the negative electrode.

[0067] In some specific embodiments, the operating temperature of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt is ≤300°C.

[0068] In some specific embodiments, the operating temperature of the membrane-free aluminum displacement battery based on the transition metal chlorination reaction in molten salt is 90–200°C, for example 90°C, 100°C, 120°C, 130°C, 150°C, 180°C, or 200°C.

[0069] Secondly, the present invention provides a method for preparing the above-mentioned membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, comprising the following steps:

[0070] A positive electrode active material, a positive electrode current collector, a negative electrode, and a separator are obtained. The positive electrode is then obtained by mixing the positive electrode active material, a conductive agent, and a binder and pressing them together.

[0071] And / or, obtain a positive electrode active material, and then dry roll-coat the surface of the current collector after mixing the positive electrode active material, conductive agent and binder to obtain a positive electrode, and then assemble it;

[0072] In some specific embodiments, the assembly method is as follows: in an inert gas atmosphere, the positive electrode is brought into contact with one side of the separator, and the other side of the separator is brought into contact with the negative electrode; powdered alkaline molten salt electrolyte is added to the battery structure; and the mixture is heated to a temperature exceeding the melting point of the alkaline molten salt electrolyte to melt the electrolyte and wet the positive electrode, the negative electrode, and the separator; or, in an inert gas atmosphere, liquid alkaline molten salt electrolyte is injected into the battery structure and wets the positive electrode, the separator, and the negative electrode, forming the core components of the battery.

[0073] The cells are then encapsulated to obtain the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt.

[0074] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0075] Example 1

[0076] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Ni-C, the negative electrode is aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.95 Cl 3.85 It includes the following steps:

[0077] 1) Preparation of Ni-C cathode:

[0078] Ni-C cathode material, acetylene black, and polytetrafluoroethylene (PTFE) were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 0.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Ni-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Ni-C positive electrode.

[0079] 2) Preparation of alkaline molten salt electrolytes:

[0080] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.95:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.95 Cl 3.85 Its melting point is approximately 120℃. Meanwhile, under the same conditions, after weighing AlCl3, NaCl, LiCl, and KCl in a molar ratio of 1.3:0.43:0.42:0.15, an acidic molten salt electrolyte Li was prepared. 0.42 Na 0.43 K 0.15 Al 1.3 Cl 4.9 It has a melting point of approximately 80°C and is used as a control.

[0081] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0082] 4) Assembly of molten salt membrane-free aluminum displacement batteries:

[0083] A Ni-C positive electrode and commercial aluminum foil were used as the positive and negative electrodes, respectively, with a glass fiber membrane as the battery separator. The Ni-C positive electrode sheet had an area of ​​0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 150℃.

[0084] Figure 1 The diagram shown illustrates the electrochemical reaction mechanism of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt in this embodiment. Figure 1 As shown, in the TM-based aluminum replacement battery, a Lewis alkaline quaternary molten salt (AlCl3-KCl-NaCl-LiCl) with an AlCl3 / ACl (A=K / Na / Li) molar ratio of 0.8–1.0 is used. This salt contains a slight excess of alkali metal chlorides in the electrolyte, and the battery operates at a temperature of 150°C. This alkaline melt is mainly composed of AlCl4. - Anions and alkali metals (A) + The composition is cations. At the positive electrode, AlCl4... - The dissociation of anions produces Cl. - Charge carriers participate in the solid-to-solid conversion reaction from TM to TMC, generating transient solid AlCl3 during the battery charging process. * (Equation 1). Transient AlCl3 * It can spontaneously react with excess ACl in molten salt electrolyte to regenerate AlCl4. - Anions (Equation 2). Therefore, the entire positive electrode reaction involves TM / ACl and TMC / A + The conversion between them (Equation 3). At the negative electrode, Al deposition / stripping occurs, accompanied by ACl precipitation / dissolution during cycling (Equation 4). The overall displacement reaction in the battery can be represented by Equation 5.

[0085] Positive electrode reaction:

[0086]

[0087] Overall positive electrode reaction:

[0088]

[0089] Negative electrode reaction:

[0090]

[0091] Overall displacement reaction:

[0092]

[0093] Figure 2 The XRD pattern of the Ni-C positive electrode active material in step 1) of this embodiment is shown. According to the comparison with the standard card, it can be seen that the peaks are consistent with those of Ni.

[0094] Figure 3 This is a typical snapshot of the AMID trajectory of the molten salt electrolyte in step 2) of this embodiment, along with the calculated percentages of different Al-Cl clusters. It can be seen that the alkaline molten salt electrolyte mainly forms AlCl4. - The dominant cluster structure is the chloroaluminate group, while acidic molten salt electrolytes contain a large number of higher-order chloroaluminate clusters.

[0095] Figure 4 The Raman spectrum of the molten salt electrolyte in step 2) of this embodiment shows that the alkaline molten salt electrolyte is AlCl4. - The characteristic peaks are mainly composed of chloroaluminate, while the characteristic peaks of higher-order chloroaluminate clusters exist in acidic molten salt electrolytes.

[0096] Figure 5 The results of ICP-AES measurements after adding excess NiCl2 to the molten salt electrolyte in step 2) of this embodiment show that Ni is essentially absent in the alkaline molten salt. 2+ The ions confirmed that controlling Lewis pH can limit the solubility of TMC.

[0097] Figure 6 The typical charge-discharge curves for the molten salt aluminum replacement battery in step 4) of this embodiment are shown, taking Al-Ni, Al-Fe, and Al-Co as examples.

[0098] Figure 7 The cycling performance of the molten salt aluminum replacement battery in step 4) of this embodiment at a current density of 0.2 A / g shows that after the first 20 cycles, the capacity decreased from 906 mAh / g to 504 mAh / g, but the capacity remained quite stable in subsequent cycles, demonstrating good capacity and stability of the battery.

[0099] Figure 8 The voltage distribution diagram of the molten salt aluminum replacement battery in step 4) of this embodiment is shown when the discharge capacity is limited to 500 mAh / g, the discharge rate is 0.2 A / g, and the charging rate is 0.2 to 5 A / g. It can be seen that when the current density is increased, the battery can still maintain good capacity of 475 and 420 mAh / g at higher charging current densities of 1 and 5 A / g, respectively, showing good rate performance.

[0100] Figure 9The above are the non-in-situ Ni 2p XPS spectra of the Ni-C cathode in the molten salt aluminum replacement battery in step 4) of this embodiment under different battery charge and discharge states. The results show the transformation process between Ni and NiCl2 during the reaction, that is, the transformation between elemental Ni and NiCl2. 2+ The transition between them.

[0101] Figure 10 The TEM and FFT images of the Ni-C cathode in the molten salt aluminum replacement battery in step 4) of this embodiment are shown in the fully charged state. The results match the plane of NiCl2, confirming that Ni has been converted into NiCl2.

[0102] Example 2

[0103] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Ni / CC, the negative electrode is made of aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.90 Cl 3.70 It includes the following steps:

[0104] 1) Preparation of Ni / CC cathode:

[0105] 3 mmol of Ni(NO3)2·6H2O, 2 mmol of NHF4, and 5 mmol of urea were dissolved in 35 mL of deionized water. The resulting solution and carbon cloth (2 cm × 4 cm) were then transferred to a 50 mL Teflon-lined autoclave and heated to 120 °C for 5 h. The mixture was washed three times with ethanol and dried overnight at 80 °C to obtain the Ni precursor / CC. Furthermore, the Ni precursor / CC was heated at 350 °C for 4 h and then treated at 500 °C for 2 h under Ar / H2 (10% H2 by volume) conditions to obtain a Ni / CC sample. This sample was then punched into 10 mm discs to serve as the Ni / CC positive electrode. During battery assembly, a 12 mm molybdenum foil current collector was placed on the non-contact side of the positive electrode to form the Ni / CC positive electrode.

[0106] 2) Preparation of alkaline molten salt electrolytes:

[0107] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.90:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K0.15 Al 0.90 Cl 3.70 Its melting point is approximately 110℃.

[0108] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0109] 4) Assembly of molten salt film-free aluminum displacement battery:

[0110] Using Ni / CC positive electrode and commercial aluminum foil as positive and negative electrodes respectively, and a glass fiber membrane as the battery separator, the Ni / CC positive electrode sheet has a diameter of 10 mm, and the diameters of the positive electrode, negative electrode and separator are 12 mm. Under inert gas protection, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator and negative electrode to assemble the core component of the molten salt aluminum battery. The core component is then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 140℃.

[0111] Figure 11 The results of step 4) of this embodiment show the long-cycle performance of the molten salt aluminum displacement battery at a discharge rate of 0.2 A / g and a high charge rate of 1 A / g. The results indicate that the battery has good long-cycle stability.

[0112] Example 3

[0113] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Fe-C, the negative electrode is made of aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.85 Cl 3.55 It includes the following steps:

[0114] 1) Preparation of Fe-C cathode:

[0115] Fe-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 0.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Fe-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Fe-C positive electrode.

[0116] 2) Preparation of alkaline molten salt electrolytes:

[0117] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.85:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.85 Cl 3.55 Its melting point is approximately 120°C.

[0118] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0119] 4) Assembly of molten salt film-free aluminum displacement battery:

[0120] Fe-C positive electrode and commercial aluminum foil were used as the positive and negative electrodes, respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Fe-C positive electrode sheet was 0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery with an operating temperature of 160℃.

[0121] The molten salt aluminum displacement battery assembled in this example has an initial discharge capacity of 458 mAh / g at a current density of 0.1 A / g, a coulombic efficiency of 93%, and good stability after 35 cycles.

[0122] Figure 12 The cost comparison of the molten salt aluminum replacement battery in step 4 of this embodiment shows that the molten salt aluminum replacement battery has a significant cost advantage over the mainstream battery system.

[0123] Example 4

[0124] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Co-C, the negative electrode is aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.80 Cl 3.4 It includes the following steps:

[0125] 1) Preparation of Co-C cathode:

[0126] Co-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 0.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Co-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Co-C positive electrode.

[0127] 2) Preparation of alkaline molten salt electrolytes:

[0128] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.80:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.80 Cl 3.4 Its melting point is approximately 120°C.

[0129] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0130] 4) Assembly of molten salt film-free aluminum displacement battery:

[0131] Co-C positive electrode and commercial aluminum foil were used as positive and negative electrodes respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Co-C positive electrode sheet was 0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery with an operating temperature of 160℃.

[0132] The molten salt aluminum displacement battery assembled in this example showed a capacity decrease from 834 mAh / g to 483 mAh / g after the first 10 cycles at a current density of 0.2 A / g, and the capacity remained quite stable in subsequent cycles, demonstrating good capacity and stability of the battery.

[0133] Example 5

[0134] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Fe-C, the negative electrode is made of aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.83 Cl 3.49 It includes the following steps:

[0135] 1) Preparation of Fe-C cathode:

[0136] Fe-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 0.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Fe-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Fe-C positive electrode.

[0137] 2) Preparation of alkaline molten salt electrolytes:

[0138] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.83:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.83 Cl 3.49 Its melting point is approximately 115℃.

[0139] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0140] 4) Assembly of molten salt film-free aluminum displacement battery:

[0141] Fe-C positive electrode and commercial aluminum foil were used as the positive and negative electrodes, respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Fe-C positive electrode sheet was 0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under inert gas protection, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery with an operating temperature of 155℃.

[0142] The molten salt aluminum displacement battery assembled in this example has an initial discharge capacity of 445 mAh / g at a current density of 0.1 A / g, a coulombic efficiency of 94%, and good stability after 30 cycles.

[0143] Example 6

[0144] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Ni-C, the negative electrode is made of aluminum-zinc alloy foil, a glass fiber membrane is used, and the electrolyte is Li. 042 Na 043 K 015 Al 086 Cl 358 It includes the following steps:

[0145] 1) Preparation of Ni-C cathode:

[0146] Ni-C cathode material, acetylene black, and PTFE were placed in a mortar in a mass ratio of 8:1.5:0.5, mixed evenly, and then dry-rolled onto a titanium foil current collector. The mixture was then cut into 12mm round discs and vacuum-dried to form the Ni-C cathode.

[0147] 2) Preparation of alkaline molten salt electrolytes:

[0148] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.86:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated at 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.86 Cl 3.58 Its melting point is approximately 112℃.

[0149] 3) Preparation of negative electrode: After cleaning the commercial aluminum-zinc alloy foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm as the negative electrode.

[0150] 4) Assembly of molten salt film-free aluminum displacement battery:

[0151] Using Ni-C positive electrode and commercial aluminum-zinc alloy foil as positive and negative electrodes respectively, and glass fiber membrane as battery separator, the diameter of Ni-C positive electrode, negative electrode and separator is 12mm. Under inert gas protection, the positive electrode is brought into contact with the first surface of the separator and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator and negative electrode to assemble the core component of the molten salt aluminum battery. The core component is then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery with an operating temperature of 150℃.

[0152] The molten salt aluminum displacement battery assembled in this example showed a capacity decrease from 891 mAh / g to 493 mAh / g after the first 10 cycles at a current density of 0.2 A / g, and the capacity remained quite stable in subsequent cycles, demonstrating good capacity and stability of the battery.

[0153] Example 7

[0154] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Co-C, the negative electrode is made of aluminum-zinc alloy foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 1.0 Cl 4.0 It includes the following steps:

[0155] 1) Preparation of Co-C cathode:

[0156] Co-C cathode material, acetylene black, and PTFE were placed in a mortar in a mass ratio of 8:1.5:0.5, mixed, and dry-rolled onto a titanium foil current collector. The mixture was then cut into 12mm round discs and vacuum-dried to form the Co-C cathode.

[0157] 2) Preparation of alkaline molten salt electrolytes:

[0158] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 1.0:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 1.0 Cl 4.0 Its melting point is approximately 110℃.

[0159] 3) Preparation of negative electrode: After cleaning the commercial aluminum-zinc alloy foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0160] 4) Assembly of molten salt membrane-free aluminum displacement batteries:

[0161] Co-C positive electrode and commercial aluminum-zinc alloy foil were used as positive and negative electrodes, respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Co-C positive electrode sheet was 0.25 cm². 2 The negative electrode and separator have a diameter of 12 mm. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 160℃.

[0162] The molten salt aluminum displacement battery assembled in this example showed a capacity decrease from 824 mAh / g to 490 mAh / g after the first 10 cycles at a current density of 0.1 A / g, and the capacity remained quite stable in subsequent cycles, demonstrating good capacity and stability of the battery.

[0163] Example 8

[0164] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Ni-C, the negative electrode is aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.95 Cl 3.85 It includes the following steps:

[0165] 1) Preparation of Ni-C cathode:

[0166] Ni-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 1.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Ni-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Ni-C positive electrode.

[0167] 2) Preparation of alkaline molten salt electrolytes:

[0168] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.95:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.95 Cl 3.85 Its melting point is approximately 120°C.

[0169] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0170] 4) Assembly of molten salt membrane-free aluminum displacement batteries:

[0171] A Ni-C positive electrode and commercial aluminum foil were used as the positive and negative electrodes, respectively, with a glass fiber membrane as the battery separator. The Ni-C positive electrode sheet had an area of ​​0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 150℃.

[0172] The molten salt aluminum displacement battery assembled in this example showed a capacity decrease from 852 mAh / g to 446 mAh / g after the first 25 cycles at a current density of 0.2 A / g, and the capacity remained quite stable in subsequent cycles, demonstrating the battery's good high load capacity and stability.

[0173] Example 9

[0174] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Fe-C, the negative electrode is made of aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.85 Cl 3.55 It includes the following steps:

[0175] 1) Preparation of Fe-C cathode:

[0176] Fe-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 1.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Fe-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Fe-C positive electrode.

[0177] 2) Preparation of alkaline molten salt electrolytes:

[0178] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.85:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.85 Cl 3.55 Its melting point is approximately 120°C.

[0179] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0180] 4) Assembly of molten salt membrane-free aluminum displacement batteries:

[0181] Fe-C positive electrode and commercial aluminum foil were used as the positive and negative electrodes, respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Fe-C positive electrode sheet was 0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 160℃.

[0182] The molten salt aluminum displacement battery assembled in this example has an initial discharge capacity of 395 mAh / g at a current density of 0.1 A / g, a coulombic efficiency of 91%, and good stability after 30 cycles.

[0183] Example 10

[0184] This embodiment provides a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt and its preparation method. The positive electrode active material is Co-C, the negative electrode is aluminum foil, a glass fiber membrane is used, and the electrolyte is Li. 0.42 Na 0.43 K 0.15 Al 0.80 Cl 3.4 It includes the following steps:

[0185] 1) Preparation of Co-C cathode:

[0186] Co-C cathode material, acetylene black, and PTFE were placed in a mortar at a mass ratio of 8:1.5:0.5, mixed evenly, and then pressed into an electrode sheet with a thickness of 1.8 mm. The sheet was then cut into several 0.25 cm pieces. 2 Co-C positive electrode sheets are prepared by vacuum drying of the electrode sheets of different sizes. During battery assembly, a 12mm molybdenum foil current collector is placed on the non-contact side of the positive electrode sheet to form the Co-C positive electrode.

[0187] 2) Preparation of alkaline molten salt electrolytes:

[0188] Under inert gas protection, AlCl3, NaCl, LiCl, and KCl were weighed out in a molar ratio of 0.80:0.43:0.42:0.15, added to a container, sealed, and transferred to an oven. The container was then heated to 160°C for 24 hours to ensure uniform mixing and complete liquefaction of the components. After cooling, the mixture was ground into powder to obtain an alkaline molten salt electrolyte. The general formula of this alkaline molten salt electrolyte is Li... 0.42 Na 0.43 K 0.15 Al 0.80 Cl 3.4 Its melting point is approximately 120°C.

[0189] 3) Preparation of negative electrode: After cleaning the commercial aluminum foil with alcohol, it is punched to obtain a circular piece with a diameter of 12mm, which is used as the negative electrode.

[0190] 4) Assembly of molten salt film-free aluminum displacement battery:

[0191] Co-C positive electrode and commercial aluminum foil were used as positive and negative electrodes respectively, and a glass fiber membrane was used as the battery separator. The area of ​​the Co-C positive electrode sheet was 0.25 cm². 2 The positive electrode, negative electrode, and separator are 12mm in diameter. Under the protection of inert gas, the positive electrode is brought into contact with the first surface of the separator, and the second surface of the separator is brought into contact with the negative electrode. Then, molten salt electrolyte is introduced and brought into contact with the positive electrode, separator, and negative electrode to assemble the core components of the molten salt aluminum battery. The core components are then encapsulated in a Swagelok-type sealed structure battery to assemble a molten salt membrane-free aluminum replacement battery. The battery operates at a temperature of 160℃.

[0192] The molten salt aluminum displacement battery assembled in this example showed a capacity decrease from 792 mAh / g to 435 mAh / g after the first 15 cycles at a current density of 0.2 A / g, and the capacity remained quite stable in subsequent cycles, demonstrating the battery's good high load capacity and stability.

[0193] Comparative Example 1

[0194] The preparation method of the aluminum battery using an acidic molten salt electrolyte provided in this comparative example is basically the same as that in Example 1, except that the acidic molten salt electrolyte obtained in Example 1 is used as the electrolyte. The test temperature of this molten salt aluminum battery is 150°C.

[0195] like Figure 13 The figure shows the initial charging curve of the aluminum battery prepared in this comparative example. From Figure 13 It can be seen that the acidic molten salt aluminum battery in Comparative Example 1 clearly failed to charge at an operating temperature of 150°C and experienced a voltage drop during the first charge. This is attributed to battery failure caused by the significant dissolution and shuttle effect of Ni in the acidic molten salt electrolyte.

[0196] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt, characterized in that, It includes a positive electrode, a negative electrode, a membrane between the positive electrode and the negative electrode, and an alkaline molten salt electrolyte; The positive electrode includes a positive electrode current collector and a positive electrode material. The positive electrode current collector includes titanium foil and / or molybdenum foil. The positive electrode material includes a positive electrode active material, which includes a transition metal and / or a chloride of a transition metal element. The negative electrode comprises metallic aluminum and / or an aluminum alloy, wherein the metallic aluminum or the aluminum alloy can simultaneously serve as the negative electrode current collector and the negative electrode active material. The alkaline molten salt electrolyte is made from an electrolyte aluminum salt and an alkali metal chloride salt.

2. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 1, characterized in that, The positive electrode active material includes one or more of Ni, Fe, Co, NiCl2, FeCl2 and CoCl2.

3. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 1, characterized in that, The diaphragm includes one or more of glass fiber diaphragms, polytetrafluoroethylene diaphragms, and filter paper.

4. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 1, characterized in that, The general formula of the alkaline molten salt electrolyte is AAl. a X b Wherein, A is selected from at least two of Ca, Mg, Li, Na, K, Rb and Cs, and X includes at least one halogen element, 0.8≤a≤1, 3.4≤b≤4, 3a+1≤b.

5. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 4, characterized in that, The halogen elements include one or more of the elements F, Cl, Br and I.

6. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 4, characterized in that, 0.83≤a≤0.95, 3.55≤b≤3.

85.

7. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 1, characterized in that, The alkaline molten salt electrolyte is liquid during battery operation and wets the positive electrode, the separator, and the negative electrode.

8. The membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 1, characterized in that, The operating temperature of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt is ≤300℃; Preferably, the operating temperature of the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt is 90–200°C.

9. A method for preparing a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt as described in any one of claims 1 to 8, characterized in that, Includes the following steps: A positive electrode active material, a positive electrode current collector, a negative electrode, and a separator are obtained. The positive electrode is obtained by mixing the positive electrode active material, a conductive agent, and a binder and then pressing it. The mixture is then assembled. And / or, obtain a positive electrode active material, and then dry roll-coat the surface of the current collector after mixing the positive electrode active material, conductive agent and binder to obtain a positive electrode, and then assemble it.

10. The method for preparing a membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt according to claim 9, characterized in that, The assembly method is as follows: In an inert gas atmosphere, the positive electrode is brought into contact with one side of the separator, and the other side of the separator is brought into contact with the negative electrode. Powdered alkaline molten salt electrolyte is added to the battery structure and heated to a temperature exceeding the melting point of the alkaline molten salt electrolyte to melt the alkaline molten salt electrolyte and wet the positive electrode, the negative electrode, and the separator. The cells are then encapsulated to obtain the membrane-free aluminum displacement battery based on the chlorination reaction of transition metals in molten salt.

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