A fully open-type long-endurance Mars battery and its preparation method

Abstract

This invention provides a fully open, long-endurance Mars battery and its fabrication method. The Mars battery comprises a vertical serpentine cell, an insertable anode current collector, a mesh cathode current collector, and a dustproof and breathable membrane. The fabrication scheme is as follows: preparation and assembly of the serpentine tubular solid electrolyte, preparation and coating of a gas diffusion and gas reaction dual-functional layer, preparation and filling of a Na / K-containing liquid alloy, integration of the rod-shaped anode and mesh cathode current collectors, and encapsulation with the dustproof and breathable membrane. The gas diffusion and gas reaction dual-functional layer is uniformly coated on the outside of the serpentine electrolyte tube, thus providing a 360° contact surface with the Martian atmosphere and exhibiting a fully open cathode characteristic, resulting in superior energy density compared to batteries with traditional single-sided gas reaction electrodes. This invention combines the advantages of solid electrolyte-based batteries—openness under the low atmospheric pressure of Mars—and the ability of the liquid alloy to fully wet the interface, coupled with the protection of the dustproof and breathable membrane, which will promote the design and development of long-endurance, all-weather Mars batteries.

Description

Technical Field

[0001] This invention belongs to the field of space battery technology, specifically relating to a fully open-type long-endurance Mars battery and its preparation method. Background Technology

[0002] Of all the planets in the solar system, Mars has the most similar physical and chemical properties to Earth, making it the ideal location for studying major scientific questions such as the origin of life and Earth's evolution. Mars rovers have multiple missions, including surface cruising and drilling for samples, and batteries, as a power source, are one of the core components of these rovers. Solar cells are currently the most widely used power source for Mars rovers, but their relatively low energy conversion efficiency and susceptibility to the Martian day-night cycle make it difficult to guarantee continuous power output. Chemical power sources, with their extremely high energy conversion efficiency and independence from sunlight, are one of the best choices for Mars batteries. To maximize the operational time of the Mars rovers before their winter hibernation, long-endurance Mars batteries are required. Developing a high-theoretical-capacity metal-carbon dioxide battery, utilizing the high CO2 electrochemically active gas content (up to 95.3%) in the Martian atmosphere, is considered a solution.

[0003] Given that Mars' atmospheric pressure is less than 1% of Earth's, traditional liquid carbon dioxide batteries are unsuitable for use as power sources due to issues such as gas production and evaporation. Using solid electrolytes instead of traditional liquid electrolytes is an effective approach. However, space exploration inevitably imposes strict limitations on the battery's size and mass. Furthermore, unattended operation could lead to long-term dust blockage of the battery's CO2 reaction side, causing battery failure. Summary of the Invention

[0004] This invention provides a fully open, long-endurance Mars battery and its preparation method. By designing a serpentine solid electrolyte and a 360° fully open CO2 reaction electrode wrapped around the electrolyte, the invention maximizes the use of the Mars probe's space volume and increases the battery's volumetric energy density. Furthermore, by using a dustproof and breathable membrane to minimize the impact of dust blockage, the invention enables the Mars probe battery to operate in all weather conditions for extended periods.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A fully open-type long-endurance Mars battery includes a vertical serpentine cell, an insertable anode current collector, a mesh cathode current collector, and a dustproof and breathable membrane.

[0007] The vertical serpentine battery cell includes a tubular serpentine solid electrolyte, a sodium-based / potassium-based liquid alloy injected into the tubular solid electrolyte tube, and a fully open gas diffusion and gas reaction dual-functional layer wrapped around the tubular solid electrolyte tube. The solid electrolyte is a solid electrolyte capable of conducting sodium or potassium ions, including Na-beta-Al₂O₃, and NASICON-type oxide solid electrolytes (Na₃Zr₂Si₂PO₄). 12 Na3Sc2P3O 12 Na 3.2 Hf2(SiO4) 2.2 (PO4) 0.8 The sodium-based / potassium-based liquid alloy is a room-temperature liquid alloy containing a sodium source or a potassium source, such as Li-Na, Na-K, Na-K-Ga, Na-Ga alloy, etc. The bifunctional layer is a combination of solid electrolyte, conductive agent (carbon nanotube, KS-6, VGCF, EC600JD, etc.) and catalyst (RuO2, Fe-NC, NaIrO3, K2RuO4, etc.).

[0008] The inserted anode current collector is a conductive metal rod inserted into the liquid alloy as an anode current collector and externally connected to the anode total current collector of the battery cell. The conductive metal rod is one or more of titanium alloy, stainless steel, copper, and silver with a diameter of about 1 to 3 mm.

[0009] The mesh cathode current collector is a mesh of conductive metal wrapped around the serpentine battery core, which is connected to the cathode current collector of the battery core and also serves to protect the dual-functional layer from falling off. The mesh cathode current collector is one or more of nickel mesh, stainless steel mesh, aluminum mesh, and gold mesh.

[0010] The dustproof and breathable membrane is a porous membrane with low dust adhesion and is wrapped around the mesh cathode current collector. The porous membrane is one or more textile membranes selected from fluorocarbon, hydrofluorocarbon, and polytetrafluoroethylene, with a pore size of 0.5 to 10 μm.

[0011] The above-mentioned method for preparing a fully open-type long-endurance Mars battery includes the following steps:

[0012] Step 1: Thoroughly ball mill and mix sodium / potassium ion conductor solid electrolyte powder (mass ratio 100:0.5-2) and low-melting-point sodium / potassium binder. Place the mixed powder in a double-layer straight tube sandwich and cold isostatically press at 250-300 MPa for 60-120 s to prepare the straight tube portion of the serpentine electrolyte. Similarly, place the mixed powder in a double-layer U-shaped tube sandwich and cold isostatically press at 200-250 MPa for 60-120 s to prepare the U-shaped tube portion of the serpentine electrolyte. Anneal the two types of electrolytes obtained at 700-1300℃ in air for 6-10 h, and then grind the burnt opening smooth for later use. The low-melting-point sodium / potassium binder is one or more of sodium tert-butoxide, sodium chloroacetate, sodium isopropoxide, disodium adipic acid, potassium acetate, potassium fluoroborate, potassium penicillin, and potassium iodate.

[0013] Step 2: Ball mill the solid electrolyte powder, isopropanol, toluene, and polyacrylamide at a mass ratio of 30-40:15-20:15-20:0.5-4 for 12 hours. Then add a certain amount of binder and plasticizer and ball mill for another 12 hours to obtain a solid electrolyte slurry. Align and connect the polished straight tube and U-shaped tube at the sintering end in a serpentine pattern. Apply the solid electrolyte slurry obtained in Step 2 evenly to the joint and quickly sinter the joint with a hydrogen torch. Repeat this process several times to obtain the desired slurry. The serpentine electrolyte is annealed in air at 700–1300℃ for 10–16 hours, and then the interface is ground smooth for use. The binder is one or more of polyvinyl butyral, guar gum, polyimide, cyclodextrin, and styrene-butadiene rubber, accounting for 2–5% of the mass of the solid electrolyte slurry. The plasticizer is one or more of butyl benzyl phthalate, dioctyl phthalate, dioctyl sebacate, and triphenyl phosphate, accounting for 3–5% of the mass of the solid electrolyte slurry.

[0014] Step 3: Ball mill the solid electrolyte powder, conductive agent, and catalyst at a mass ratio of 4-6:2-4:0.5-2 for 2-6 hours to mix them evenly. Mix the powder with NMP solution containing PVDF (PVDF is 5% by mass) at a mass ratio of 1:4-6 to form a cathode slurry. Apply the cathode slurry evenly to the outside of the serpentine electrolyte obtained in Step 2. Then transfer the coated electrolyte to a high-temperature furnace filled with argon and heat it at 500-900℃ for 15 minutes. After natural cooling, use chemical vapor deposition to deposit a layer of photothermal conversion material on the cathode surface to further improve the battery's daytime working ability. This results in a fully open gas diffusion and gas reaction dual-functional layer wrapped around the tubular solid electrolyte tube. Then, tightly wrap a mesh current collector around the outside of the dual-functional layer as the cathode current collector and lead out multiple cathode wires through segmented interfaces. Stand the serpentine electrolyte upright and drill holes on the top and sides of the U-shaped tube for later use. The photothermal material is one or more of PdSe2, Co, Au film, black titanium dioxide, and graphene aerogel.

[0015] Step 4: Insert two metal rod current collectors with a diameter of 0.5-2mm into the cell through holes drilled on both sides, and seal both sides with silicone rubber. In an argon-filled glove box, place sodium, potassium, and gallium blocks in a stainless steel container at a mass ratio of 20-30:40-60:10-20 and leave at room temperature overnight to obtain a room temperature liquid Na-K-Ga alloy. Inject the obtained Na-K-Ga alloy into the serpentine electrolyte tube through the top hole, and then seal all openings with silicone rubber.

[0016] Step 5: Wrap a single-layer porous dustproof and breathable membrane evenly around the mesh cathode current collector and heat-seal the membrane ends. Finally, connect multiple cathode and anode wires to the battery management system to obtain a fully open, long-endurance Mars battery.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) This invention achieves the maximum energy conversion active area by using a snake-shaped battery structure and a 360° fully open CO2 reaction electrode design, while maximizing the space volume occupied by the power unit of the Mars probe. This ensures the high capacity and long endurance of the Mars battery. In addition, the vertical snake-shaped battery cell and the dustproof and breathable membrane can ensure that the CO2 reaction electrode is in full contact with the Martian atmosphere, and can also avoid the adverse effects of dust adhering to the open electrode by using low dust adhesion ability and gravity dust falling.

[0019] (2) The sodium / potassium-based liquid alloy (such as Na-K-Ga) used in this invention has good fluidity and contains Ga components that wet the electrolyte, which can fully contact the electrolyte and ensure excellent interfacial contact of the battery. In addition, the sodium / potassium-based liquid alloy has a low melting point (below -20°C) and can maintain dynamic wetting in the low temperature environment of Mars. Even if the temperature drops further and the liquid alloy solidifies, the phase change of the liquid alloy will generate heat to heat the battery. In addition, based on the good contact of the liquid alloy in the early stage, even if it solidifies, it will maintain good contact with the electrode.

[0020] (3) The solid electrolyte used in this invention avoids the penetration and leakage of traditional liquid electrolytes in the low-pressure Martian environment. In addition, the plasma cathode formed by the photothermal conversion material of chemical vapor deposition can effectively absorb sunlight during the day on Mars and convert it into heat, thereby realizing effective charge storage and transmission in the electrolyte / electrode material. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the Mars battery of the present invention;

[0022] Figure 2a This is a schematic diagram of the straight tube of the tubular serpentine electrolyte of the present invention;

[0023] Figure 2b This is a schematic diagram of the U-shaped tube of the tubular serpentine electrolyte of the present invention;

[0024] Figure 3 This is a schematic diagram of the connected tubular serpentine electrolyte of the present invention;

[0025] Figure 4 This is a schematic diagram of the present invention involving coating a bifunctional layer on the outer surface of a serpentine electrolyte;

[0026] Figure 5 For the present invention in Figure 3 A schematic diagram of adding a mesh cathode current collector to the existing structure;

[0027] Figure 6 This is a schematic diagram illustrating the further infusion of liquid alloy and the addition of an anode current collector in this invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] The fully open-type long-endurance Mars battery in this embodiment is as follows: Figure 1 As shown, the preparation method is carried out according to the following steps:

[0031] (1) Na3Zr2Si2PO4 in a mass ratio of 100:1 12 Solid electrolyte powder and sodium isopropoxide were thoroughly ball-milled and mixed. The mixed powder was then placed in a double-layer straight tube sandwich and cold isostatically pressed at 280 MPa for 90 s to prepare the straight tube portion of the serpentine electrolyte. Figure 2a As shown, the mixed powder was placed in a double-layered U-shaped tube sandwich and cold isostatically pressed at 220 MPa for 90 s to prepare the U-shaped tube portion of the serpentine electrolyte, as shown. Figure 2b As shown, the two types of electrolytes obtained were annealed in air at 1200℃ for 8 hours, and then the burnishing opening was polished smooth for later use.

[0032] (2) Na3Zr2Si2PO 12Solid electrolyte powder, isopropanol, toluene, and polyacrylamide were ball-milled for 12 hours at a mass ratio of 35:18:18:2. Then, 4% polyvinyl butyral and 5% butyl benzyl phthalate were added and ball-milled for another 12 hours to obtain a solid electrolyte slurry. The polished straight tube and U-shaped tube obtained in step (1) were aligned and connected in a serpentine pattern at their sintering points. The solid electrolyte slurry obtained in step (2) was evenly applied to the joint, and the joint was rapidly sintered using a hydrogen torch. After repeating this process several times, the resulting serpentine electrolyte was annealed in air at 1200°C for 12 hours. The joint was then polished smooth for later use. Figure 3 As shown;

[0033] (3) Na3Zr2Si2PO 12 Solid electrolyte powder, VGCF, and NaIrO3 were ball-milled for 4 hours at a mass ratio of 5:3:1 to form a uniform mixture. The mixed powder was then stirred with a PVDF-containing NMP solution (5% PVDF NMP solution) at a mass ratio of 1:4 to form a cathode slurry. The cathode slurry was then uniformly coated onto the outside of the serpentine electrolyte obtained in step (2). The coated electrolyte was then transferred to a high-temperature furnace filled with argon gas and heated at 700°C for 15 minutes. After natural cooling, a layer of PdSe2 photothermal conversion material was deposited on the cathode surface using chemical vapor deposition to further improve the daytime working capacity of the battery. This resulted in a fully open gas diffusion and gas reaction dual-functional layer wrapped around the tubular solid electrolyte tube, such as... Figure 4 As shown, a stainless steel mesh current collector is then tightly wound around the outside of the dual-functional layer as a cathode current collector, as follows. Figure 5 As shown, multiple cathode wires are led out using segmented interfaces, the serpentine electrolyte is erected, and holes are drilled at the top and sides of the U-shaped tube for later use;

[0034] (4) Insert two 1mm diameter titanium rod current collectors into the cell through holes drilled on both sides, seal both sides with silicone rubber, and place sodium, potassium, and gallium blocks in a stainless steel container in an argon-filled glove box at a mass ratio of 10:7:2. Leave it overnight at room temperature to obtain a room-temperature liquid Na-K-Ga alloy. Inject the obtained Na-K-Ga alloy into the serpentine electrolyte tube through the drilled holes, and then seal all openings with silicone rubber. Figure 6 As shown;

[0035] (5) A single-layer porous polytetrafluoroethylene dustproof and breathable membrane is evenly wrapped around a stainless steel mesh cathode current collector, and the ends of the breathable membrane are heat-sealed. Finally, multiple cathode and anode wires are connected to the battery management system to obtain a fully open, long-endurance Mars battery. Figure 1 As shown.

[0036] Example 2:

[0037] The difference between this embodiment and Embodiment 1 is that the K-ion solid conductor K2Fe4O7 is used instead of the sodium-ion solid conductor Na3Zr2Si2PO4. 12 Therefore, the energy conversion in this embodiment is based on a K-CO2 battery, while the energy conversion in Example 1 is based on a Na-CO2 battery.

[0038] (1) K2Fe4O7 solid electrolyte powder and potassium penicillin with a mass ratio of 100:0.8 were thoroughly ball-milled and mixed. The mixed powder was placed in a double-layer straight tube sandwich and cold isostatically pressed at 260MPa for 60s to prepare the straight tube part of the serpentine electrolyte. Similarly, the mixed powder was placed in a double-layer U-shaped tube sandwich and cold isostatically pressed at 200MPa for 60s to prepare the U-shaped tube part of the serpentine electrolyte. The two types of electrolytes were annealed in air at 700℃ for 8h. Then the burnt opening was polished flat for later use.

[0039] (2) K2Fe4O7 solid electrolyte powder, isopropanol, toluene and polyacrylamide are ball-milled for 12 hours at a mass ratio of 50:15:15:2. Then, 3.5% polyvinyl butyral and 4% butyl benzyl phthalate are added and ball-milled for 12 hours to obtain solid electrolyte slurry. The polished straight tube and U-shaped tube obtained in step (1) are aligned and connected in a serpentine manner. The solid electrolyte slurry obtained in step (2) is evenly applied to the interface and the interface is quickly sintered with a hydrogen torch. After repeating this several times, the obtained serpentine electrolyte is annealed in air at 700°C for 6 hours. Then, the interface is polished flat for use.

[0040] (3) K2Fe4O7 solid electrolyte powder, VGCF and K2RuO4 are ball-milled for 4 hours at a mass ratio of 8:3:1. The mixed powder is stirred with NMP solution containing PVDF (NMP solution with 5% PVDF mass fraction) at a mass ratio of 1:4 to form a cathode slurry. The cathode slurry is evenly coated on the outside of the serpentine electrolyte obtained in step (2). Then the coated electrolyte is transferred to a high-temperature furnace filled with argon and heated at 500°C for 15 minutes. After natural cooling, a layer of PdSe2 photothermal conversion material is deposited on the cathode surface by chemical vapor deposition to further improve the daytime working ability of the battery. A fully open gas diffusion and gas reaction dual-function layer is obtained wrapped around the tubular solid electrolyte tube. Then, a stainless steel mesh current collector is tightly wound around the outside of the dual-function layer as a cathode current collector. Multiple cathode wires are led out with segmented interfaces. The serpentine electrolyte is erected and holes are drilled on the top and sides of the U-shaped tube for later use.

[0041] (4) Insert two titanium rod current collectors with a diameter of 1 mm into the cell through holes drilled on both sides, seal both sides with silicone rubber, place sodium blocks, potassium blocks and gallium blocks in a stainless steel container in an argon-filled glove box at a mass ratio of 5:8:2, and leave them overnight at room temperature to obtain room temperature liquid Na-K-Ga alloy. Inject the obtained Na-K-Ga alloy into the serpentine electrolyte tube through the drilled holes, and then seal all openings with silicone rubber.

[0042] (5) Wrap a single-layer porous polytetrafluoroethylene dustproof and breathable membrane evenly around a stainless steel mesh cathode current collector and heat-seal the membrane ends. Finally, connect multiple cathode wires and anode wires to the battery management system to obtain a fully open long-endurance Mars battery.

[0043] This invention, based on the deformation resistance and sealable protection of sensitive components of solid electrolytes, designs a Martian battery based on a tubular, serpentine solid electrolyte. The fluidity of the liquid alloy enhances the interfacial wetting of the negative electrode and the electrolyte. Furthermore, the tubular electrolyte allows the bifunctional layer of the positive electrode to encapsulate the solid electrolyte in a 360° omnidirectional manner, significantly increasing the battery's active reaction area, thereby improving the battery's energy density and endurance. The use of a porous, dustproof, and breathable membrane, along with the vertical integration method, ensures sufficient CO2 content in the bifunctional reaction layer, preventing battery failure caused by Martian dust storms clogging the porous reaction electrodes.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a fully open-type long-endurance Mars battery, wherein the fully open-type long-endurance Mars battery comprises a vertical serpentine cell, an inserted anode current collector, a mesh cathode current collector, and a dustproof and breathable membrane; The vertical serpentine battery cell includes a tubular serpentine solid electrolyte, a sodium-based / potassium-based liquid alloy injected into the tubular solid electrolyte tube, and a fully open gas diffusion and gas reaction dual-functional layer wrapped around the tubular solid electrolyte tube. The inserted anode current collector is a conductive metal rod inserted into the liquid alloy as an anode current collector, and is externally connected to the anode current collector of the battery cell. The mesh cathode current collector is a mesh of conductive metal wrapped around the serpentine battery core, which is connected to the cathode current collector of the battery core. The dustproof and breathable membrane is a porous membrane with low dust adhesion and is wrapped around the mesh cathode current collector. Its features are, The preparation method includes the following steps: Step 1: Thoroughly ball mill and mix sodium / potassium ion conductor solid electrolyte powder (mass ratio 100:0.5~2) and low-melting-point sodium / potassium-containing binder. Place the mixed powder in a double-layer straight tube sandwich and cold isostatically press at 250~300 MPa for 60~120 s to prepare the straight tube part of the serpentine electrolyte. Similarly, place the mixed powder in a double-layer U-shaped tube sandwich and cold isostatically press at 200~250 MPa for 60~120 s to prepare the U-shaped tube part of the serpentine electrolyte. Anneal the two types of electrolytes obtained at 700~1300 ℃ in air for 6~10 h, and then grind the burnt end smooth for later use. Step 2: Ball mill the solid electrolyte powder, isopropanol, toluene, and polyacrylamide at a mass ratio of 30-40:15-20:15-20:0.5-4 for 12 hours. Then add a certain amount of binder and plasticizer and ball mill for another 12 hours to obtain a solid electrolyte slurry. Align and connect the polished straight tube and U-shaped tube at the sintering end in a serpentine manner. Apply the solid electrolyte slurry obtained in Step 2 evenly to the joint and quickly sinter the joint with a hydrogen torch. Repeat this process several times. Then anneal the obtained serpentine electrolyte in air at 700-1300 °C for 10-16 hours. Finally, polish the joint to make it smooth for use. Step 3: Ball mill the solid electrolyte powder, conductive agent and catalyst at a mass ratio of 4~6:2~4:0.5~2 for 2~6 hours to mix them evenly. Mix the powder with NMP solution containing PVDF at a mass ratio of 1:4~6 to form a cathode slurry. Coat the cathode slurry evenly on the outside of the serpentine electrolyte obtained in Step 2. Then transfer the coated electrolyte to a high-temperature furnace filled with argon and heat it at 500~900 ℃ for 15 min. After natural cooling, deposit a layer of photothermal conversion material on the cathode surface using chemical vapor deposition to obtain a fully open gas diffusion and gas reaction dual-functional layer wrapped around the tubular solid electrolyte tube. Then tightly wrap the mesh current collector around the outside of the dual-functional layer as the cathode current collector and lead out multiple cathode wires with segmented interfaces. Stand the serpentine electrolyte upright and drill holes on the top and sides of the U-shaped tube for later use. Step 4: Insert two metal rod current collectors with a diameter of 0.5~2 mm into the cell through holes drilled on both sides, seal both sides with silicone rubber, and place sodium blocks, potassium blocks and gallium blocks in a stainless steel container in an argon-filled glove box at a mass ratio of 20~30:40~60:10~20. Leave at room temperature overnight to obtain room temperature liquid Na-K-Ga alloy. Inject the obtained Na-K-Ga alloy into the serpentine electrolyte tube through the drilled holes, and then seal all openings with silicone rubber. Step 5: Wrap a single-layer porous dustproof and breathable membrane evenly around the mesh cathode current collector and heat-seal the membrane ends. Finally, connect multiple cathode and anode wires to the battery management system to obtain a fully open, long-endurance Mars battery.

2. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: In step one, the low-melting-point sodium / potassium binder is one or more of the following: sodium tert-butoxide, sodium chloroacetate, sodium isopropoxide, disodium adipic acid, potassium acetate, potassium fluoroborate, potassium penicillin, and potassium iodate.

3. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: In step two, the binder is one or more of polyvinyl butyral, guar gum, polyimide, cyclodextrin, and styrene-butadiene rubber, accounting for 2-5% of the mass of the solid electrolyte slurry; The plasticizer is one or more of butyl benzyl phthalate, dioctyl phthalate, dioctyl sebacate, and triphenyl phosphate, accounting for 3-5% of the mass of the solid electrolyte slurry.

4. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: In step three, the photothermal conversion material is one or more of PdSe2, Co, Au thin film, black titanium dioxide, and graphene aerogel.

5. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: The solid electrolyte is a solid electrolyte that can conduct sodium or potassium ions, including Na-beta-Al2O3, NASICON-type oxide solid electrolyte, and K2Fe4O7. The liquid alloy is a room temperature liquid alloy containing a sodium source or a potassium source; The bifunctional layer comprises a solid electrolyte, a conductive agent, and a catalyst.

6. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: The conductive metal rod is one or more of titanium alloy, stainless steel, copper, and silver with a diameter of 1-3 mm. The mesh cathode current collector is one or more of nickel mesh, stainless steel mesh, aluminum mesh, and gold mesh.

7. The method for preparing a fully open-type long-endurance Mars battery according to claim 1, characterized in that: The porous membrane is one or more textile membranes selected from fluorocarbon, hydrofluorocarbon, and polytetrafluoroethylene, with a pore size of 0.5~10 μm.

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