A copper-coated tin powder negative material, a preparation method and application thereof

Abstract

This invention discloses a copper-coated tin powder anode material, its preparation method, and its application, belonging to the field of aqueous tin metal battery technology. Addressing the problems of hydrogen evolution, corrosion side reactions, unstable interparticle electrical contact, and "dead tin" accumulation caused by the high specific surface area of ​​tin powder anodes in alkaline electrolytes, this invention proposes the following technical solution: First, the tin powder is pretreated with citric acid solution to remove the surface oxide layer. Then, the pretreated tin powder is added to a copper plating solution containing copper salts and citric acid. The plating process involves the interaction of tin with Cu... 2+ The liquid-phase displacement reaction forms a copper coating layer and a copper-tin alloy interface in situ on the surface of tin powder particles, resulting in a copper-coated tin powder anode material for application in aqueous tin-metal batteries. This invention can suppress hydrogen evolution, corrosion, and "dead tin" formation in tin powder anodes, and promote the formation of Sn(OH)3. ‑ Uniform deposition improves battery rate performance, coulombic efficiency, and cycle life.

Description

Technical Field

[0001] This invention belongs to the field of aqueous tin metal battery technology, specifically relating to a copper-coated tin powder anode material, its preparation method, and its application. Background Technology

[0002] With the development of large-scale energy storage, grid peak shaving, and distributed energy systems, electrochemical energy storage technology faces higher demands in terms of safety, cost, and sustainability. Aqueous batteries, using water as the electrolyte solvent, offer advantages such as intrinsic non-flammability, high ionic conductivity, low cost, and environmental friendliness, making them suitable for energy storage scenarios with high safety and economic requirements. Current research on aqueous metal batteries mainly focuses on zinc, magnesium, and aluminum anode systems. Among these, aqueous zinc-ion batteries have seen rapid development, but zinc anodes are prone to dendrite growth, hydrogen evolution, and corrosion during long-cycle periods, affecting battery life and safety. Therefore, developing novel aqueous metal anode systems is of great significance.

[0003] Tin anodes possess high theoretical specific capacity, low redox potential, and good corrosion resistance, making them promising candidates for use in aqueous tin-metal batteries. Unlike zinc anodes, the isotropic deposition of tin makes it more prone to forming granular deposits rather than sharp dendrites, which helps reduce the risk of short circuits caused by dendrites puncturing the separator.

[0004] Current research on aqueous tin-metal batteries primarily uses tin foil as the anode, which suffers from low utilization of active tin and limited flexibility in capacity control. Tin powder anodes, however, offer advantages such as adjustable morphology and particle size, lower cost, and higher utilization of active tin, making them promising candidates for constructing high-utilization tin-based anodes. However, tin powder anodes have a large specific surface area, making them prone to hydrogen evolution reactions, corrosion side reactions, and surface passivation in alkaline electrolytes. Furthermore, the electrical contact stability between tin powder particles is poor, leading to localized deposition imbalances, active material shedding, and "dead tin" accumulation during cycling, resulting in decreased coulombic efficiency and shortened cycle life.

[0005] Because copper and tin have a good affinity and can form a stable copper-tin alloy phase interface, constructing a uniform copper coating layer on the surface of tin powder particles can not only improve the electrical contact between particles and build a conductive framework, but also provide stable tin-affinity nucleation sites, inducing Sn(OH)3. - Uniform adsorption and deposition can potentially solve problems such as severe side reactions, uneven deposition, and "dead tin" accumulation during the tin powder anode cycling process. Summary of the Invention

[0006] The purpose of this invention is to provide a copper-coated tin powder anode material, its preparation method, and its application. This method constructs a copper coating layer and a copper-tin alloy interface in situ on the surface of tin powder particles through a liquid-phase displacement reaction, thereby suppressing hydrogen evolution and corrosion side reactions, inducing uniform tin nucleation and deposition, improving the electrical contact state between tin powder particles, reducing the formation of "dead tin," and enhancing the cycle stability and coulombic efficiency of aqueous tin metal batteries.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a copper-coated tin powder anode material includes: pretreating tin powder in a citric acid aqueous solution to remove the oxide layer on the surface of the tin powder, obtaining pretreated tin powder; adding the pretreated tin powder to a copper plating solution containing copper salt and citric acid, and reacting the tin powder with Cu... 2+ The liquid-phase displacement reaction causes copper to be reduced and deposited on the surface of tin powder particles; after the reaction is completed, vacuum filtration, washing and drying are performed to obtain copper-coated tin powder anode material.

[0008] Preferably, the concentration of the citric acid aqueous solution is 0.05-0.20 mol / L. -1 More preferably 0.10 mol L -1 .

[0009] Preferably, the copper salt is copper sulfate, and the concentration of copper sulfate in the copper plating solution is 0.005-0.020 mol / L. -1 The concentration of citric acid was 0.010-0.040 mol / L. -1 .

[0010] Preferably, the copper plating solution contains Cu 2+ The molar ratio with citric acid is 1:2. Citric acid, as a complexing agent, can control Cu. 2+ The release rate and displacement reaction process should be controlled to avoid uneven copper layer deposition caused by excessively rapid local reactions.

[0011] Preferably, the liquid phase displacement reaction time is 30 min, and the drying conditions are vacuum drying at 60 ℃ for 8 h.

[0012] The present invention also provides a copper-coated tin powder anode material prepared by the above method. The material has tin powder particles as the core and a copper coating layer as the outer layer, forming a copper-tin alloy interface between the tin powder and the copper coating layer.

[0013] The present invention also provides an aqueous tin metal battery anode containing the above-mentioned copper-coated tin powder anode material and its application in aqueous tin metal batteries.

[0014] The present invention has the following beneficial effects: (1) The present invention uses liquid phase displacement method to construct copper coating layer in situ on the surface of tin powder. The process is simple, the reaction conditions are mild, and it is easy to scale up.

[0015] (2) The present invention removes the oxide layer on the surface of tin powder by pretreatment with citric acid, which is beneficial to the subsequent Cu 2+ A uniform displacement reaction occurs on the surface of the tin powder, thereby improving the uniformity and stability of the copper coating.

[0016] (3) In this invention, the copper coating layer has good tin affinity, which can provide uniform nucleation sites for tin deposition and promote Sn(OH)3 deposition. - Uniform adsorption and deposition on the negative electrode surface alleviates the problems of uneven deposition / stripping and "dead tin" accumulation.

[0017] (4) The present invention constructs a copper coating layer in situ on the surface of tin powder particles by liquid phase displacement, which can improve the electrical contact between tin powder particles, construct a continuous conductive path, and improve the structural stability of the powder negative electrode.

[0018] (5) The copper coating layer of the present invention can reduce the erosion of the tin powder anode by the electrolyte and suppress interfacial side reactions such as hydrogen evolution and corrosion, thereby improving the cycle life, coulombic efficiency and rate performance of aqueous tin metal batteries. Attached Figure Description

[0019] Figure 1 Scanning electron microscope image and energy dispersive spectroscopy (EDS) elemental distribution map of the copper-coated tin powder anode material Sn@Cu-0.01 prepared in Example 1 of this invention.

[0020] Figure 2 The X-ray diffraction patterns of the unmodified tin powder material Sn in Comparative Example 1 and the copper-coated tin powder anode material Sn@Cu-0.01 prepared in Example 1 are shown below.

[0021] Figure 3 In-situ optical microscope images of the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1 during the electrodeposition process of this invention.

[0022] Figure 4 The images show scanning electron microscope images of the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1 after constant current deposition.

[0023] Figure 5 The graph shows the cycle performance of a symmetrical battery assembled with the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1.

[0024] Figure 6The coulombic efficiency diagrams of the asymmetric cells assembled with the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1 are shown.

[0025] Figure 7 The graph shows the rate performance of a tin-iodine full cell assembled with the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1.

[0026] Figure 8 The graph shows the cycle performance of a tin-iodine full cell assembled with the Sn anode in Comparative Example 1 and the Sn@Cu-0.01 anode prepared in Example 1. Detailed Implementation

[0027] This invention provides a method for preparing copper-coated tin powder anode material, comprising the following steps: (1) Add tin powder to a citric acid aqueous solution for pretreatment to remove the oxide layer on the surface of the tin powder particles and obtain pretreated tin powder; (2) The pretreated tin powder obtained in step (1) is added to a copper plating solution containing copper salt and citric acid to carry out a liquid-phase chemical displacement reaction, so that Cu 2+ A copper coating layer is formed by reduction deposition on the surface of tin powder particles, resulting in copper-coated tin powder material. (3) The copper-coated tin powder material obtained in step (2) is subjected to solid-liquid separation, washing and drying to obtain copper-coated tin powder anode material.

[0028] In this invention, the concentration of the citric acid aqueous solution is preferably 0.01-0.20 mol / L. -1 More preferably 0.10 mol L -1 The pretreatment time is preferably 1-10 min, more preferably 5 min. The role of citric acid pretreatment is to remove the oxide layer on the surface of the tin powder particles, improve the reactivity of the tin powder surface, and facilitate subsequent Cu... 2+ A uniform displacement reaction occurs on the surface of the tin powder particles.

[0029] In this invention, the copper salt preferably includes one or more of copper sulfate, copper chloride, and copper acetate, more preferably copper sulfate. The copper salt concentration in the copper plating solution is preferably 0.001-0.050 mol / L. -1 More preferably, it is 0.005-0.020 mol L. -1 Copper salts are used to provide Cu. 2+ This allows the tin powder to be reduced and form a copper coating layer on the surface through a liquid-phase displacement reaction.

[0030] In this invention, the concentration of citric acid in the copper plating solution is preferably 0.001-0.200 mol / L. -1More preferably, it is 0.010-0.040 mol L. -1 The Cu 2+ The molar ratio with citric acid is preferably 1:1 to 1:4, more preferably 1:2. Citric acid, as a complexing agent, can adjust the Cu content. 2+ The release rate and liquid-phase displacement reaction process are optimized to avoid uneven copper layer deposition caused by excessively rapid local reactions, thereby improving the uniformity and stability of the copper coating.

[0031] In this invention, the liquid-phase displacement reaction time is preferably 10-60 min, more preferably 30 min. If the reaction time is too short, the copper coating layer on the surface of the tin powder particles will not form sufficiently; if the reaction time is too long, the copper layer may be over-deposited or locally agglomerated, which is not conducive to the formation of a uniform and stable copper coating structure.

[0032] In this invention, the solid-liquid separation method is preferably vacuum filtration. The washing is preferably performed using deionized water until the filtrate is neutral. The drying method is preferably vacuum drying, with a drying temperature preferably 40-80 °C, more preferably 60 °C; the drying time is preferably 4-12 h, more preferably 8 h. The main function of drying is to remove residual moisture from the material surface, obtaining a stable copper-coated tin powder anode material.

[0033] This invention also provides a copper-coated tin powder anode material obtained by the above preparation method. The copper-coated tin powder anode material includes tin powder particles and a copper coating layer formed on the surface of the tin powder particles. Preferably, the copper coating layer is a continuous or semi-continuous coating layer. More preferably, a copper-tin alloy interface is formed between the tin powder particles and the copper coating layer. The copper coating layer has good tin affinity and can be Sn(OH)3. - The adsorption and deposition of tin provide nucleation sites, thereby promoting uniform deposition of tin.

[0034] This invention also provides a copper-coated tin powder anode containing the aforementioned copper-coated tin powder anode material. The copper-coated tin powder anode material is mixed with a dispersant and then loaded onto a mesh current collector. The dispersant is preferably one of deionized water, N-methylpyrrolidone (NMP), or anhydrous ethanol, more preferably NMP. The mesh current collector is preferably one of stainless steel mesh, titanium mesh, or nickel foam, more preferably stainless steel mesh. The areal loading of the copper-coated tin powder anode material is preferably 50-150 mg / cm³. -2 More preferably 70-80 mg cm -2 The pressing pressure of the copper-coated tin powder negative electrode is preferably 5-20 MPa, more preferably 10 MPa. The pressing process can enhance the contact between the copper-coated tin powder particles and the current collector, and improve the overall structural stability of the electrode.

[0035] This invention also provides the application of the above-mentioned copper-coated tin powder anode material or copper-coated tin powder anode in an aqueous tin-metal battery. The anode electrolyte of the aqueous tin-metal battery preferably includes an alkali, a stannous salt, and deionized water. The alkali is preferably one or more of potassium hydroxide and sodium hydroxide, more preferably potassium hydroxide; the concentration of the alkali is preferably 1-6 mol / L. -1 More preferably 3 mol L -1 The stannous salt is preferably one or more of stannous sulfate and stannous chloride, more preferably stannous sulfate; the concentration of the stannous salt is preferably 0.05-0.5 mol / L. -1 More preferably 0.1 mol L -1 .

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0037] Example 1 This embodiment provides a method for preparing a copper-coated tin powder anode material, the specific steps of which are as follows: Weigh 1.9 g of citric acid and dissolve it in 100 mL of deionized water to prepare a 0.1 mol L solution. -1 Citric acid aqueous solution. Then, 1.2 g of metallic tin powder was weighed and added to the above citric acid aqueous solution. After stirring for 5 min, it was vacuum filtered and washed with deionized water until neutral to obtain pretreated tin powder.

[0038] Weigh 0.16 g of copper sulfate and 0.38 g of citric acid and dissolve them in 100 mL of deionized water to prepare a solution containing 0.01 mol / L. -1 Copper sulfate and 0.02 mol L -1 A citric acid-based copper plating solution was prepared. The pretreated tin powder was added to the copper plating solution and stirred continuously for 30 minutes to allow the Cu plating process to complete. 2+ A liquid-phase displacement reaction occurs on the surface of tin powder particles, followed by in-situ reduction deposition. After the reaction, the material is vacuum filtered and washed with deionized water until neutral. Then, it is vacuum dried at 60 °C for 8 h to obtain copper-coated tin powder anode material, denoted as Sn@Cu-0.01.

[0039] Comparative Example 1 This comparative example provides a tin powder anode material without copper coating. Metallic tin powder is used directly as the anode active material without citric acid pretreatment or liquid-phase displacement reaction, denoted as Sn. This sample serves as a control to evaluate the impact of the copper coating layer on the structure, deposition behavior, and electrochemical performance of the tin powder anode material.

[0040] Application Example 1 This application example provides a method for preparing a copper-coated tin powder negative electrode.

[0041] The Sn@Cu-0.01 powder obtained in Example 1 was mixed with NMP and stirred to form a uniform slurry. The slurry was then uniformly coated onto a stainless steel mesh current collector, vacuum dried at 60 °C for 8 h, and compacted under a pressure of 10 MPa to obtain the Sn@Cu-0.01 anode.

[0042] Following the same method, the Sn powder from Comparative Example 1 was used to prepare Sn anodes. The active material surface loading of the resulting Sn anode and Sn@Cu-0.01 anode was 70-80 mg / cm³. -2 .

[0043] Application Example 2 This application example provides assembly methods for Sn||Sn symmetric cells and Sn||Cu asymmetric cells.

[0044] Preparation of negative electrode electrolyte: Weigh 1.68 g potassium hydroxide and 0.21 g stannous sulfate, dissolve them in deionized water, and bring the volume to 10 mL to obtain 3 mol L⁻¹ electrolyte. -1 KOH + 0.1 mol L -1 SnSO4 electrolyte.

[0045] Two Sn anodes were used as symmetrical electrodes, with cellophane as the separator, and 80 μL of anode electrolyte was added. The Sn||Sn symmetrical cell was then assembled using a CR2025 coin cell mold. Following the same method, two Sn@Cu-0.01 anodes were used as symmetrical electrodes to assemble a Sn@Cu-0.01||Sn@Cu-0.01 symmetrical cell.

[0046] Using Sn or Sn@Cu-0.01 negative electrode as the working electrode, copper foil as the counter electrode, cellophane as the separator, and 80 μL of negative electrode electrolyte, Sn||Cu asymmetric cells and Sn@Cu-0.01||Cu asymmetric cells were assembled respectively.

[0047] Application Example 3 This application example provides assembly methods for Sn||I2 full cells and Sn@Cu-0.01||I2 full cells.

[0048] Activated carbon, Ketjen black, and PTFE were mixed in a mass ratio of 7:2:1, and anhydrous ethanol was used as a dispersant to prepare a slurry. The slurry was then pressed onto a titanium mesh current collector and dried to obtain an iodine cathode support. Subsequently, iodine active material was loaded onto the above cathode support to obtain an iodine cathode.

[0049] Preparation of positive electrode electrolyte: Weigh 4.98 g of potassium iodide, dissolve it in deionized water, and bring the volume to 10 mL to obtain 3 mol L⁻¹ electrolyte. -1 KI electrolyte.

[0050] Using either a Sn or Sn@Cu-0.01 anode as the negative electrode and an iodine cathode as the positive electrode, the positive and negative electrodes were separated by a Nafion 117 ion exchange membrane. 150 μL of electrolyte was added to each electrode side to assemble Sn||I2 full cells and Sn@Cu-0.01||I2 full cells, respectively.

[0051] Test Example 1 The Sn@Cu-0.01 powder prepared in Example 1 was subjected to scanning electron microscopy and energy dispersive spectroscopy (EDS) elemental distribution analysis. The results are as follows: Figure 1 As shown. By Figure 1 It can be seen that Sn@Cu-0.01 powder maintains the basic morphology of tin powder particles, and copper elements are uniformly distributed on the surface of tin powder particles, indicating that a relatively uniform copper coating layer is constructed on the surface of tin powder particles through liquid phase displacement method.

[0052] Test Example 2 X-ray diffraction analysis was performed on the Sn@Cu-0.01 powder in Example 1 and the Sn powder in Comparative Example 1. The results are as follows: Figure 2 As shown. By Figure 2 It can be seen that, in addition to retaining the characteristic diffraction peaks of metallic Sn, the Sn@Cu-0.01 sample also showed diffraction signals related to the copper-tin alloy phase, indicating that a copper-tin alloy interface was formed on the surface of the tin powder particles during the liquid phase displacement process.

[0053] Test Example 3 The changes of the Sn anode and Sn@Cu-0.01 anode during the electrodeposition process were observed in situ using optical microscopy, and the results are as follows: Figure 3 As shown. The test conditions were: current density 3 mA cm⁻¹ -2 Deposition time: 15 min. (By...) Figure 3 It can be seen that the Sn anode surface exhibits obvious bubbles and uneven deposition during the deposition process, indicating that the hydrogen evolution side reaction is relatively serious and the tin deposition process is unstable. In contrast, the Sn@Cu-0.01 anode surface has almost no bubbles, and the deposition process is more uniform and smooth, indicating that the copper coating reduces the hydrogen evolution tendency and improves the tin deposition behavior.

[0054] Test Example 4 After constant current deposition of Sn and Sn@Cu-0.01 anodes, the surface morphology after deposition was observed using scanning electron microscopy. The results are as follows: Figure 4 As shown. The deposition conditions were: current density 1 mA cm⁻¹. -2 Deposition capacity 30 mAh cm⁻¹ -2 .Depend on Figure 4 It can be seen that the Sn anode surface is relatively rough after deposition, the deposits are unevenly distributed, and there is a loose accumulation phenomenon; while the Sn@Cu-0.01 anode surface deposit layer is denser and more uniform, without obvious large-sized deposit agglomerates. This result indicates that the copper coating layer can provide uniform tin-affinity nucleation sites, promoting Sn(OH)3. - Uniform adsorption and deposition on the negative electrode surface reduces the formation of "dead tin".

[0055] Test Example 5 The Sn||Sn symmetric cells and Sn@Cu-0.01||Sn@Cu-0.01 symmetric cells assembled in Case 2 were subjected to constant current charge-discharge cycle tests, and the results are as follows: Figure 5 As shown. The test conditions were: current density 1 mA cm⁻¹. -2 Surface capacity 0.5 mAh cm -2 .Depend on Figure 5 It can be seen that the Sn@Cu-0.01||Sn@Cu-0.01 symmetric cell has a cycle life of 600 cycles, which is 76% higher than that of the Sn||Sn symmetric cell. This indicates that the copper coating improves the structural stability of the tin powder anode during repeated deposition / stripping.

[0056] Test Example 6 The Sn||Cu asymmetric battery and Sn@Cu-0.01||Cu asymmetric battery assembled in Case 2 were subjected to charge-discharge cycle tests, and the results are as follows. Figure 6 As shown. The test conditions were: current density 1 mA cm⁻¹. -2 Charging cutoff voltage 0.4 V, discharge surface capacity 0.5 mAh cm⁻¹ -2 .Depend on Figure 6 As can be seen, compared with the Sn||Cu asymmetric cell, the Sn@Cu-0.01||Cu asymmetric cell exhibits a longer cycle life and a higher average coulombic efficiency, at 400 cycles and 99.82%, respectively. This indicates that the copper coating improves the reversibility of the tin deposition / stripping process and suppresses side reactions such as hydrogen evolution and the loss of active tin.

[0057] Test Example 7 Rate performance tests were conducted on the Sn||I2 full cell and Sn@Cu-0.01||I2 full cell assembled in use case 3, and the results are as follows. Figure 7As shown. Test conditions: The charging process was a constant voltage of 1.6 V until the areal capacity reached 1 mAh cm⁻¹. -2 The current densities during the discharge process were 10, 20, 40, 80, 120, and 160 mA cm⁻¹. -2 The cutoff voltage is 0.3 V. (By...) Figure 7 It can be seen that the Sn@Cu-0.01||I2 full cell exhibits higher discharge capacity and better rate stability under different current densities, indicating that the copper-coated tin powder anode can improve the reaction kinetics and stability of the full cell under high current density.

[0058] Test Example 8 Cyclic tests were performed on the Sn||I2 full cell and Sn@Cu-0.01||I2 full cell assembled in test case 3, and the results are as follows. Figure 8 As shown. Test conditions: The charging process was a constant voltage of 1.6 V until the areal capacity reached 1 mAh cm⁻¹. -2 The current density during the discharge process is 40 mA cm⁻¹. -2 The cutoff voltage is 0.3 V. (By...) Figure 8 It can be seen that the Sn@Cu-0.01||I2 full cell achieved a cycle life of 2000 cycles while retaining approximately 100% of its capacity. This result indicates that the copper-coated tin powder anode material prepared in this invention effectively improves the long-cycle stability of aqueous tin metal full cells.

Claims

1. A method for preparing a copper-coated tin powder anode material, characterized in that, The liquid-phase chemical displacement method includes the following steps: (1) Add tin powder to a citric acid aqueous solution for pretreatment to obtain pretreated tin powder; (2) adding the pretreated tin powder obtained in step (1) into a copper plating solution containing a copper salt and citric acid to perform a liquid phase displacement reaction, so as to make Cu 2+ The copper-coated tin powder negative material is obtained by reducing and forming a copper coating layer on the surface of the tin powder particles, then performing solid-liquid separation, washing and drying.

2. The preparation method according to claim 1, characterized in that, The tin powder in step (1) is metallic tin powder, and the concentration of the citric acid aqueous solution is 0.01-0.20 mol / L. -1 .

3. The preparation method according to claim 1, characterized in that, The pretreatment process in step (1) includes: stirring at a speed of 200-600 r / min for 1-10 min, and then washing with deionized water until neutral to obtain tin powder with the surface oxide layer removed.

4. The preparation method according to claim 1, characterized in that, The copper salt in step (2) is one or more of copper sulfate, copper chloride, and copper acetate.

5. The preparation method according to claim 1, characterized in that, The copper salt concentration in the copper plating solution in step (2) is 0.001-0.050 mol / L. -1 The concentration of citric acid is 0.001-0.200 mol / L. -1 .

6. The preparation method according to claim 1, characterized in that, The liquid phase displacement reaction time in step (2) is 10-60 min.

7. The preparation method according to claim 1, characterized in that, The drying temperature in step (2) is 40-80℃ and the time is 4-12 h.

8. The copper-coated tin powder anode material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The copper-coated tin powder anode material maintains the basic morphology of the tin powder particles, with a diameter of 20 μm.

9. A water-based tin metal battery, characterized in that, The copper-coated tin powder anode material as described in claim 1 is applied to an aqueous tin metal battery.

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