CN116914283A - An aqueous organic hybrid secondary calcium ion battery based on electrochemically formed calcium alloy negative electrode and its application - Google Patents

Abstract

The invention belongs to the technical field of calcium ion batteries and discloses an aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of a calcium alloy negative electrode and its application. The aqueous organic hybrid secondary calcium ion battery includes a battery negative electrode, an electrolyte, a separator, and a battery positive electrode. The battery negative electrode is a calcium alloy negative electrode; the electrolyte is an aqueous-organic hybrid calcium ion electrolyte; and the active material of the positive electrode is Prussian blue active material. Materials: Aqueous-organic hybrid calcium ion electrolyte is obtained by mixing organic solvent, calcium salt and deionized water and stirring thoroughly. The calcium alloy negative electrode of the calcium ion battery prepared in situ by the present invention significantly improves the reversibility of the deposition and stripping of calcium ions in the electrolyte, reduces the passivation reaction of calcium metal, and the prepared secondary calcium ion battery exhibits more excellent high voltage platform and long cycle life advantages. At the same time, the electrode and electrolyte raw materials are cheap and easy to obtain, the preparation cost is low, the time is short, safe and environmentally friendly, and it has good application prospects.

Description

A water-based organic hybrid secondary calcium ion based on electrochemical formation of calcium alloy negative electrode Batteries and their applications

Technical field

The invention belongs to the technical field of calcium ion batteries, and specifically relates to an aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of a calcium alloy negative electrode and its application.

Background technique

Energy is an eternal topic in human society. Lithium-ion batteries have achieved great success over the past few decades in powering electric vehicles and portable electronics. As demand for electrochemical energy storage systems increases from growing smart grid and electrified transportation applications, raw material supply issues are a concern. Considering that lithium resources are limited and unevenly distributed, multivalent ion batteries are considered very promising in the search for new sustainable and economical batteries. Among them, calcium-ion batteries have low redox potential of calcium metal (-2.9V vs. SHE) and high abundance of calcium (4.1% in the earth's crust), which is 2500 times richer than lithium. They are green, environmentally friendly and non-toxic, so calcium-ion batteries received widespread attention.

At present, the development of calcium-ion batteries is still in its preliminary stages. Regardless of the type of cathode or anode material or electrolyte, there is an urgent need to develop materials with high capacity, good cycle performance and good electrochemical stability. In particular, the calcium metal anode in calcium-ion batteries suffers from serious passivation problems. Compared with Li or Na metal, Ca metal anode is less likely to form dendrites and is expected to improve battery safety. However, divalent calcium ions interact strongly with active calcium metal, cathode materials, and non-aqueous electrolyte solutions, resulting in high charge transfer barriers at the electrode-electrolyte interface, resulting in poor electrochemical performance of the battery. Therefore, it is necessary to further study the interface chemistry and design a suitable electrode-electrolyte interface, that is, to design a calcium anode and a calcium salt electrolyte that are compatible with each other, as well as a high-performance cathode that is highly compatible with them, and to reduce the charge transfer potential at the electrode-electrolyte interface. Barriers are crucial for realizing high-performance calcium-ion batteries.

Contents of the invention

In order to solve the deficiencies and shortcomings of the above-mentioned prior art, the primary purpose of the present invention is to provide an aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of a calcium alloy negative electrode, which can effectively improve the charge transfer potential at the electrode-electrolyte interface. The problem of high barrier is solved, thus solving the problems of low voltage, poor cycle performance and high cost of secondary calcium ion batteries in the existing technology.

Another object of the present invention is to provide the application of the above-mentioned secondary calcium ion battery.

The object of the present invention is achieved through the following technical solutions:

An aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of a calcium alloy negative electrode, including a battery negative electrode, an electrolyte, a separator and a battery positive electrode. The battery negative electrode is a calcium alloy negative electrode; the electrolyte is a water-organic Hybrid calcium ion electrolyte; the active material of the battery positive electrode is Prussian blue active material; the water-organic hybrid calcium ion electrolyte is made by mixing organic solvents, calcium salts and deionized water, and stirring them thoroughly get.

Preferably, the calcium alloy negative electrode is obtained by polishing the metal foil to remove the surface oxide layer, then soaking the polished metal foil with dilute acid to remove the residual oxide layer, and finally cleaning it with deionized water and absolute ethanol. Metal foil with the surface oxide layer removed; cut the metal foil with the oxide layer removed, and use the metal foil pieces as the positive and negative electrodes of the symmetrical battery, using an aqueous-organic hybrid calcium ion electrolyte as the electrolyte, Assemble a CR2032 button battery, disassemble the battery after charge and discharge cycles; or directly use metal foil alloyed with calcium ions as the negative electrode current collector. After the battery is assembled, the metal foil forms a calcium alloy in situ. .

More preferably, the metal foil is zinc foil, tin foil, nickel foil, molybdenum foil, copper foil, or manganese foil.

More preferably, the dilute acid is dilute hydrochloric acid, dilute sulfuric acid or dilute nitric acid, and the concentration of the dilute acid is 0.5-2 mol/L.

Preferably, the organic solvent is at least one of nitrile organic solvents, ether organic solvents, and ester organic solvents.

More preferably, the nitrile organic solvent is at least one of acetonitrile, succinonitrile or adiponitrile; the ether organic solvent is ethylene glycol dimethyl ether or/and triethylene glycol dimethyl ether. ; The ester organic solvent is at least one of propylene carbonate, ethylene carbonate, and diethyl carbonate.

Preferably, the calcium salt is calcium triflate, calcium bis(trifluoromethanesulfonyl)imide, calcium bisfluorosulfonimide, calcium perchlorate, calcium tetrafluoroborate, hexafluorophosphoric acid One or more of calcium, calcium nitrate, calcium fluoride, and calcium chloride.

Preferably, the Prussian blue active material is nickel manganese Prussian blue, manganese Prussian blue, copper Prussian blue or cobalt Prussian blue. The Prussian blue cathode active material can be quickly produced by methods commonly used in the industry, such as common co-precipitation methods, hydrothermal synthesis methods, and ball milling methods.

The Prussian blue active material, conductive carbon and binder are dissolved and slurried with a solvent to obtain a slurry, which is then coated on the current collector, dried in vacuum, and cut to the required size to obtain the battery positive electrode.

Preferably, the molar ratio of the organic solvent, calcium salt and deionized water is 1:(10~30):(10~30).

Application of the secondary calcium ion battery in energy storage equipment or electrical equipment.

The secondary calcium ion battery of the present invention includes a metal foil negative electrode prepared from a calcium alloy negative electrode, an aqueous organic hybrid electrolyte, and a Prussian blue positive electrode. The positive electrode includes a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer includes conductive carbon, a binder and the positive electrode active material. The conductive carbon and binder can be any carbon material with conductive properties known to those skilled in the battery field, as well as any material in which the active material is adhered and compounded on the current collector, preferably polyvinylidene fluoride and carboxymethyl fiber. Polytetrafluoroethylene, polyvinyl alcohol, etc. The current collector can be any current collector recognized by those skilled in the battery field, preferably graphite paper and stainless steel mesh. The content of conductive carbon in the cathode material is preferably 10-15%, the content of the binder in the cathode material is preferably 10-15%, and the preferred content of the cathode active material is 70-80%. The calcium alloy negative electrode is directly generated in the electrochemical charge-discharge reaction, so when preparing a secondary calcium ion battery, the above-mentioned metal foil can be directly used as a negative electrode current collector.

Compared with the prior art, the present invention has the following beneficial effects:

1. The calcium alloy negative electrode of the calcium ion battery prepared in situ by the present invention significantly improves the reversibility of the deposition and stripping of calcium ions in the electrolyte, reduces the passivation reaction of calcium metal, and the prepared secondary calcium ion battery exhibits more excellent performance High voltage platform and long cycle life advantages. The prepared calcium alloy negative electrode uses low-cost, safe and harmless metal foil as the substrate for electrochemical preparation of alloys. Compared with the expensive and easily oxidized calcium metal, the prepared calcium alloy has low cost, simple preparation steps, and a mild and controllable preparation process. At the same time, during electrochemical charge and discharge, the calcium alloy can greatly alleviate the violent passivation reaction between calcium metal and electrolyte, and improve the reversibility of calcium ion deposition and stripping at the anode-electrolyte interface.

2. The number of cycles of the secondary calcium metal battery prepared by the present invention can reach 400 cycles, and the voltage platform is up to 1.85V. This electrochemical stability and working voltage have far exceeded that of calcium metal batteries directly assembled using expensive calcium metal. The raw materials are cheap and easy to obtain, the preparation cost is low, the time is short, it is safe and environmentally friendly, and it has good application prospects.

3. The calcium alloy negative electrode of the present invention uses the metal foil substrate directly as the negative electrode current collector, and forms a calcium alloy through an in-situ electrochemical reaction during the battery charging and discharging process to serve as the negative electrode of the secondary calcium ion battery. This type of alloy negative electrode can be obtained directly through electrochemical methods and does not require complicated preparation processes. Compared with the expensive and easily passivated calcium metal anode, directly using a metal foil substrate as the current collector of the anode has the advantages of being green, environmentally friendly, and low-cost.

4. The calcium alloy negative electrode formed by in-situ electrochemistry of the present invention utilizes its alloy interface layer to effectively alleviate the calcium metal passivation problem and inhibit dendrite growth, ensuring ultra-long-term stable calcium stripping/electroplating; using the calcium alloy formed in-situ The secondary calcium-ion battery with the negative electrode exhibits excellent discharge voltage, which is better than many other calcium-ion batteries. Compared with the secondary calcium-ion battery using calcium metal as the negative electrode, it shows an extremely significant advantage in battery cycle life.

5. The water molecules in the aqueous-organic hybrid electrolyte of the present invention play a strong lubrication and shielding role, prompting large-sized Ca ²⁺ to be quickly embedded and extracted in the Prussian blue active material, and improving the diffusion of battery cathode materials. Kinetics; at the same time, the organic components in the hybrid electrolyte can effectively inhibit the decomposition of water molecules in the electrolyte, broaden the electrochemical window of the electrolyte, and slow down the inevitable calcium metal passivation reaction on the negative electrode. The aqueous-organic hybrid calcium ion electrolyte of the present invention has high purity, good chemical stability, good compatibility with conventional electrode materials, high ion conductivity and ion mobility, simple preparation method, and mild and controllable conditions. .

6. In the aqueous-organic hybrid calcium ion electrolyte prepared by the present invention, the strong lubrication and shielding effect of the water solvent significantly promotes the rapid transportation of large-sized Ca ²⁺ , thereby promoting the large amount of Ca ²⁺ in the Prussian blue cathode. store. At the same time, the composition of the organic solvent significantly inhibits the decomposition of H ₂ O and reduces the inevitable generation of calcium metal by-products. Therefore, the Prussian blue cathode exhibits excellent electrochemical stability and fast calcium ion diffusion kinetics in this aqueous-organic hybrid electrolyte, and is compatible with the stable calcium alloy anode, making the prepared secondary calcium ion battery ultimately Exhibits excellent cycling stability.

Description of the drawings

Figure 1 is a cross-sectional scanning electron microscope (SEM) photo of the calcium-zinc alloy negative electrode electrochemically prepared in Example 1.

Figure 2 is the X-ray diffraction pattern (XRD) of the calcium-zinc alloy negative electrode and zinc foil electrochemically prepared in Example 1.

Figure 3 is a selected area electron diffraction pattern (SAED) of the calcium-zinc alloy negative electrode electrochemically prepared in Example 1.

Figure 4 is a time-voltage curve of the zinc substrate symmetrical battery of Example 1 when the areal current density is 0.2mA cm ^-2 and the areal capacity density is 0.2mAh cm ^-2 .

Figure 5 Charging and discharging curves of the secondary calcium ion battery assembled in Example 1 at a current density of 0.1A/g

Figure 6 is a rate performance diagram of the secondary calcium ion battery assembled in Example 1.

Figure 7 is a graph showing the cycle stability of the secondary calcium ion battery assembled in Example 1 at a current density of 1A/g.

Figure 8 is a time-voltage curve of the calcium metal symmetrical battery of Comparative Example 2 when the areal current density is 0.2mA cm ^-2 and the areal capacity density is 0.2mAh cm ^-2 .

Figure 9 is the charge and discharge curve of the secondary calcium ion battery assembled in Comparative Example 2 at a current density of 0.1A/g.

Figure 10 is a rate performance diagram of the secondary calcium ion battery assembled in Comparative Example 2.

Detailed ways

The content of the present invention will be further described below with reference to specific examples, but should not be understood as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

Example 1

1. Preparation of water-acetonitrile hybrid electrolyte

Mix calcium trifluoromethanesulfonate, organic solvent acetonitrile and deionized water at a molar ratio of 1:20:20, and stir thoroughly for 12 hours to obtain a well-dispersed water-acetonitrile hybrid calcium ion electrolyte (1-20- 20).

2. Preparation of electrochemically formed calcium-zinc alloy negative electrode

(1) Take a zinc foil with a thickness of 100 μm to remove the surface oxide layer. First, use sandpaper to remove most of the ZnO oxide layer on the surface of the zinc foil. Then, soak the polished zinc foil in 1 mol/L HCl for 1 min to remove the residue. ZnO oxide layer.

(2) Use the zinc foil with the ZnO oxide layer removed in step (1) as the electrode, use the aqueous-acetonitrile hybrid calcium ion electrolyte 1-20-20 as the electrolyte, and glass fiber as the separator to assemble a CR2032 button battery. A symmetrical battery was produced.

(3) Charge and discharge the symmetrical battery assembled in step (2) on a constant current charge and discharge tester with an area current density of 0.1 to 0.3 mAcm ^-2 and an area capacity density of 0.1 to 0.3 mAh cm ^-2 . Cycle The time is 50~100h.

(4) Disassemble the symmetrical battery after the electrochemical cycle in step (3), and its electrode is a calcium-zinc alloy negative electrode.

The calcium-zinc alloy in the calcium-zinc alloy negative electrode is formed in situ during the electrochemical charge and discharge process, and can be quickly prepared and used in the preparation of various equipment materials.

3. Preparation of nickel manganese Prussian blue active material

(1) Weigh 2g of trisodium citrate dihydrate, 0.539g of NiCl ₂ ·6H ₂ O and 0.278g of Mn(CH ₃ CO ₂ ) ₂ ·4H ₂ O, and dissolve them in 100 mL of deionized water to obtain a solution A.

(2) Weigh 2.06g of Na ₄ Fe(CN) ₆ ·10H ₂ O and dissolve it in 100 mL of deionized water to obtain solution B.

(3) Add solution A dropwise to solution B, and stir thoroughly for 24 hours at room temperature and pressure. After stirring is completed, it is aged for 24 hours. Finally, the aged solution was centrifuged and washed twice with deionized water, and dried in a vacuum oven at 80°C for 12 hours to obtain the nickel manganese Prussian blue active material (NiMnPB).

4. Preparation of secondary calcium ion batteries

Take 40 mg of the active material NiMnPB prepared above and 5 mg of conductive carbon black Super-P, thoroughly mix and grind for 30 minutes, then add 250 mg of polyvinylidene fluoride with a mass fraction of 2% and stir for 12 hours to obtain a uniform slurry. Apply the slurry evenly Apply it on the graphite paper current collector and vacuum dry it at 80°C for 24 hours to obtain the NiMnPB positive electrode piece.

Use the water-acetonitrile hybrid calcium ion electrolyte 1-20-20 as the electrolyte, glass fiber as the separator, the calcium zinc alloy prepared in step 2 as the negative electrode, and the NiMnPB positive electrode sheet as the positive electrode to assemble a CR2032 button battery. , to prepare secondary calcium ion batteries.

5. Performance testing of secondary calcium ion batteries and symmetrical batteries

The prepared secondary calcium ion battery was tested for constant current charge and discharge performance. The charge cut-off voltage was 2.2V and the discharge cut-off voltage was 0.2V.

Figure 1 is a cross-sectional scanning electron microscope (SEM) photo of the calcium-zinc alloy negative electrode electrochemically prepared in Example 1. As can be seen from Figure 1, the cross-section of the calcium-zinc alloy negative electrode is very smooth, indicating that the calcium-zinc alloy does not have the common dendrite growth problem in lithium-ion batteries during the formation process. This ensures that the secondary calcium-ion battery will not suffer from dendrites. Crystal growth problems cause battery short circuits, causing serious safety issues. Figure 2 is the X-ray diffraction pattern (XRD) of the calcium-zinc alloy negative electrode and zinc foil electrochemically prepared in Example 1. The analysis in Figure 2 shows that the diffraction angle of the calcium-zinc alloy negative electrode is obviously shifted to a lower diffraction angle than that of the zinc foil. This is due to the influence of the calcium-zinc alloy effect, which proves the formation of the calcium-zinc alloy. Figure 3 is a selected area electron diffraction pattern (SAED) of the calcium-zinc alloy negative electrode electrochemically prepared in Example 1. The analysis in Figure 3 further proves that the calcium-zinc alloy negative electrode was successfully synthesized.

Figure 4 is a time-voltage curve of the calcium-zinc alloy symmetrical battery of Example 1 when the areal current density is 0.2mA cm ^-2 and the areal capacity density is 0.2mAh cm ^-2 . As can be seen from Figure 4, the hysteresis voltage of the zinc substrate symmetrical battery is very small (about 0.044V), and it can cycle stably for more than 1600 hours, which shows that the calcium zinc alloy formed in situ can effectively reduce the charge transfer potential at the electrode-electrolyte interface barrier, thus improving the reversibility of calcium ion deposition and stripping at the electrode-electrolyte interface. Figure 5 is the charge and discharge curve of the secondary calcium ion battery assembled in Example 1 at a current density of 0.1 A/g. As can be seen from Figure 5, the secondary calcium ion battery assembled in Example 1 also exhibits an excellent high voltage platform at a current density of 0.1A/g. The voltage platform is as high as 1.85V, and the average discharge voltage is 1.52V. Figure 6 is a rate performance diagram of the secondary calcium ion battery assembled in Example 1. It can be seen from Figure 6 that after cycling at a high current density of 5A/g, the current density returns to a current density of 0.1A/g, and still exhibits a capacity of 144mAh/g. It can be seen that the rate of the secondary calcium ion battery assembled in Example 1 is stable. The performance is very excellent. Figure 7 is a graph showing the cycle stability of the secondary calcium ion battery assembled in Example 1 at a current density of 1A/g. As can be seen from Figure 7, the secondary calcium ion battery assembled in Example 1 can be stable for 400 cycles at a current density of 1A/g for a long time. This stability far exceeds the cycle stability of most secondary calcium ion batteries using expensive calcium metal as the negative electrode. sex.

Example 2

In the preparation process of the symmetrical battery and the secondary calcium ion battery in Example 1, except for the molar ratio of water solvent to acetonitrile solvent in the water-acetonitrile hybrid calcium ion electrolyte used, all other steps and materials used are the same. . The aqueous-acetonitrile hybrid calcium ion electrolyte (1-10-30) used in Example 2 is miscible with calcium trifluoromethanesulfonate, acetonitrile, and deionized water at a molar ratio of 1:10:30;

Example 3

The aqueous-acetonitrile hybrid calcium ion electrolyte (1-30-10) used in Example 3 is miscible with calcium trifluoromethanesulfonate, acetonitrile, and deionized water at a molar ratio of 1:30:10;

Example 4

The difference from Example 1 is that the negative electrode in the secondary calcium ion battery assembly is a zinc foil with the oxide layer removed as the negative electrode substrate (current collector), which can generate a calcium-zinc alloy negative electrode during the electrochemical cycle. The prepared secondary calcium ion battery has basically the same electrochemical properties as the symmetrical battery, and the preparation is more convenient and faster than in Example 1.

Comparative example 1

Comparative Example 1 used a calcium ion acetonitrile electrolyte solution (1-40) miscible with calcium trifluoromethanesulfonate and acetonitrile at a molar ratio of 1:40.

The symmetrical batteries of Examples 1-3 and Comparative Example 1 were subjected to conventional cycle stability tests at an areal current density of 0.5mAcm ^-2 and an areal capacity density of 0.5mAh cm ^-2 . The stability of the symmetrical batteries is shown in Table 1.

Table 1 Stability of symmetrical batteries of Examples 1-3 and Comparative Example 1

Table 1 shows the stability of the symmetrical batteries of Examples 1-3 and Comparative Example 1. As can be seen from Table 1, compared with Comparative Example 1, Examples 1-3 introduce water molecules into the electrolyte, which greatly improves the cycle life of the symmetrical battery of Examples 1-3 compared with Comparative Example 1. This is because the introduction of water molecules promotes the formation of calcium-zinc alloy on the electrode surface, allowing the calcium ions at the electrode-electrolyte interface to be stably deposited and peeled off, thereby increasing the cycle life of the symmetrical battery. At the same time, compared with Examples 2 and 3, Example 1 has the longest cycle time of the symmetrical battery, indicating that the calcium ion deposition and peeling stability in the electrode-electrolyte interface is the best. Water-acetonitrile hybrid electrolyte 1-20 -20 is the optimal hybrid electrolyte, which can effectively reduce the charge transfer barrier at the electrode-electrolyte interface and help achieve reversible and stable electrochemical deposition stripping of calcium ions.

Comparative example 2

In the preparation process of the symmetrical battery and the secondary calcium-ion battery in Comparative Example 2 and Example 1, except for the negative electrode used in the symmetrical battery and the secondary calcium-ion battery, which is calcium metal, the charge-discharge interval selection of the secondary calcium-ion battery is 0.4 Except for -2.2V, all other steps and materials used are the same. Figure 8 is a time-voltage curve of the calcium metal symmetrical battery of Comparative Example 2 when the areal current density is 0.2mAcm ^-2 and the areal capacity density is 0.2mAh cm ^-2 . As can be seen from Figure 8, the maximum voltage hysteresis of the calcium metal symmetric battery in Comparative Example 2 is about 0.34V in the first 5 cycles, but the voltage hysteresis increases sharply (about 2.23V) after the 6th cycle. It can be seen that the voltage hysteresis of a symmetrical battery using calcium metal as an electrode changes greatly during the cycle, indicating that the deposition and stripping reaction of calcium ions on calcium metal is extremely difficult and unstable.

The stability of the symmetrical batteries of Example 1 and Comparative Example 2 at an area current density of 0.2 mA cm ^-2 and an area capacity density of 0.2 mAh cm ^-2 is shown in Table 2.

Table 2 Stability of symmetrical batteries of Example 1 and Comparative Example 2

Table 2 shows the stability of the symmetrical batteries of Example 1 and Comparative Example 2. It can be seen from Table 2 that under the water-acetonitrile hybrid calcium ion electrolyte 1-20-20, the active calcium metal and the water-acetonitrile hybrid calcium ion electrolyte solution still interact strongly, causing the passivation problem of calcium metal and Gas production is a serious problem. Therefore, the charge transfer barrier at the calcium metal-electrolyte interface is very high, ultimately leading to very poor electrochemical performance of the symmetrical cell, which can only operate for 7 hours. On the contrary, the calcium-zinc alloy negative electrode formed by in-situ electrochemistry in the present invention can effectively alleviate calcium metal passivation through alloying, inhibit dendrite growth, and ensure ultra-long and stable calcium stripping/electroplating. Conventional cycle stability tests were conducted at 0.2mAcm ^-2 and areal capacity density 0.2mAh cm ^-2 , and the cycle time even exceeded 1600h.

Figure 9 is the charge and discharge curve of the secondary calcium ion battery assembled in Comparative Example 2 at a current density of 0.1A/g. It can be seen from Figure 9 that since calcium metal has a low redox potential, the voltage platform of the secondary calcium ion battery assembled in Comparative Example 2 is as high as about 1.93V at a current density of 0.1A/g. Figure 10 is a rate performance diagram of the secondary calcium ion battery assembled in Comparative Example 2. It can be seen from Figure 10 that the secondary calcium ion battery assembled in Comparative Example 2 has a capacity of almost 0 after 6 cycles of the rate stability test. This is due to the rapid passivation of the calcium metal negative electrode during the electrochemical reaction, resulting in calcium loss. The failure of the metal negative electrode ultimately restricted the cycle life of the secondary calcium ion battery produced in Comparative Example 2.

To sum up, directly use metal foil that can form an alloy with calcium ions as the negative electrode current collector. After the battery is assembled, the metal foil will form a calcium alloy in situ, or directly use electrochemically prepared calcium alloy as the electrode. Both methods The electrochemical stability is better than that of calcium metal.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, etc. may be made without departing from the spirit and principles of the present invention. All simplifications should be equivalent substitutions, and are all included in the protection scope of the present invention.

Claims (10)

1. An aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of a calcium alloy negative electrode, including a battery negative electrode, an electrolyte, a separator and a battery positive electrode, characterized in that the battery negative electrode is a calcium alloy negative electrode; The electrolyte is aqueous-organic hybrid calcium ion electrolyte; the active material of the battery positive electrode is Prussian blue active material; the aqueous-organic hybrid calcium ion electrolyte is a mixture of organic solvent, calcium salt and deionized water Mix well and stir thoroughly. 2. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 1, characterized in that the calcium alloy negative electrode is made by polishing a metal foil to remove the surface oxide layer, and then using The polished metal foil is soaked in dilute acid to remove the residual oxide layer, and finally cleaned with deionized water and absolute ethanol to obtain a metal foil with the surface oxide layer removed; the metal foil with the oxide layer removed is cut into pieces, and Metal foil cutting pieces are used as the positive and negative electrodes of a symmetrical battery, and aqueous-organic hybrid calcium ion electrolyte is used as the electrolyte to assemble a CR2032 button battery. The battery is disassembled after charging and discharging cycles; or directly A metal foil alloyed with calcium ions is used as the negative electrode current collector. After the battery is assembled, the metal foil forms a calcium alloy in situ. 3. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 2, characterized in that the metal foil is zinc foil, tin foil, nickel foil, molybdenum foil, copper foil foil or manganese foil. 4. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 2, characterized in that the dilute acid is dilute hydrochloric acid, dilute sulfuric acid or dilute nitric acid, and the dilute acid is The concentration is 0.5~2mol/L. 5. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 1, characterized in that the organic solvent is a nitrile organic solvent, an ether organic solvent, an ester organic solvent. More than one solvent. 6. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 5, characterized in that the nitrile organic solvent is one of acetonitrile, succinonitrile or adiponitrile. More than one kind; the ether organic solvent is ethylene glycol dimethyl ether or/and triethylene glycol dimethyl ether; the ester organic solvent is one of propylene carbonate, ethylene carbonate or diethyl carbonate. above. 7. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 1, characterized in that the calcium salt is calcium trifluoromethanesulfonate, bis(trifluoromethyl Calcium sulfonyl)imide, calcium bisfluorosulfonimide, calcium perchlorate, calcium tetrafluoroborate, calcium hexafluorophosphate, calcium nitrate, calcium fluoride, and calcium chloride. 8. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 1, characterized in that the Prussian blue active material is nickel manganese Prussian blue, manganese Prussian blue, copper Prussian blue Or Cobalt Prussian Blue. 9. The aqueous organic hybrid secondary calcium ion battery based on the electrochemical formation of calcium alloy negative electrode according to claim 1, characterized in that the molar ratio of the organic solvent, calcium salt and deionized water is 1:(10 ~30):(10~30). 10. Application of the secondary calcium ion battery according to any one of claims 1 to 9 in energy storage equipment or electrical equipment.