CN111816890A - A kind of fluid seawater battery and preparation method - Google Patents

Abstract

The invention discloses a fluid seawater battery and a preparation method, belonging to the technical field of hybrid batteries and manufacturing. The method includes the following aspects: 1) a cathode material dominated by fluid coordination crystals that provides storage sites for ions in seawater, and exhibits reversible charge-discharge characteristics of secondary batteries; 2) a metal with a lower redox potential Anode materials dominated by magnesium and aluminum are used to provide electrons until the metal is consumed. This is a typical primary battery feature; 3) A seawater solution with at least 1 ppm of dissolved oxygen and at least 0.35% of sodium chloride is used as the electrolyte to balance the polarization of the ion concentration in the electrode during the power generation process and stabilize the power generation device. surroundings. When the ion storage sites in the coordination crystals are completely occupied, the ions in the storage sites are released by using dissolved oxygen in seawater to react with the coordination crystals, thereby realizing the recycling of the coordination crystals. The method of the invention is easy to operate, the material is environmentally friendly, can be recycled, and can meet general use.

Description

A kind of fluid seawater battery and preparation method

technical field

The invention relates to the technical field of hybrid batteries and their manufacture, in particular to a fluid seawater battery and a preparation method.

Background technique

With the proposal of my country's marine power strategy, the problems of ocean power consumption and island power supply need to be solved urgently. The existing power supply methods are mainly networked and off-grid; the networked power grid is mainly through submarine cables. Although the networking project can ensure the reliability of the island’s power supply, its amazing cost and difficulties in subsequent maintenance make the island. Off-grid power supply has become the core technology of island power supply. The island off-grid power supply system uses renewable energy, such as photovoltaic power generation, wind energy, etc., but the island environment is high temperature, high humidity, high salt fog, photovoltaic power generation devices need to undergo special treatment under such conditions, economical and applicable type still needs to be improve. In response to the above series of problems, in recent years, researchers at home and abroad have shifted their perspectives to seawater, the most abundant resource in islands. Attempts to use natural seawater as an electrolyte to generate electricity led to the emergence of seawater batteries. The outstanding feature of seawater batteries is that they do not need to carry electrolytes and can work in the environment of all sea conditions. The seawater battery adopts the working principle of a primary battery. The anode is an active metal, and the cathode is an electrode of silver chloride, cuprous chloride and lead chloride. The characteristics of this type of seawater battery are high energy density and high power, but during the discharge process , by consuming the positive anode material, it belongs to a primary battery, and the economy is not good, so it is mainly used in the military as a power source for torpedoes; another type of metal-air seawater battery that is more researched, that is, the anode still uses active metals, while The cathode directly reduces the electrode with dissolved oxygen in seawater. Compared with the previous type of battery, the anode still needs to consume active metals, while the cathode consumes the dissolved oxygen in seawater for redox reactions. This type of battery not only has the characteristics of a primary battery, but also has the characteristics of a fuel cell. However, due to the limitation of its working principle, that is, the limitation of the dissolved oxygen concentration of the cathode material, the power of the battery has always been a big problem. The existing battery system can only be applied to low-power electrical appliances at sea, such as buoys, lighthouses, etc. Therefore, seeking a cathode material with better efficacy and higher efficiency can create a seawater battery with better comprehensive performance.

Coordination crystals are a kind of three-dimensional periodic porous framework materials formed by metal ions or clusters as nodes and organic ligands as frameworks. Coordination crystals have the advantages of high porosity, low density, large specific surface area, adjustable pore size, and topology diversity and tailorability. Therefore, coordination crystals can be used for metal ions (such as potassium ions, sodium ions, etc.). Reversible storage. In addition, its crystal structure can remain stable during the intercalation and deintercalation of guest ions. In recent years, coordination crystals, represented by Prussian blue compounds, have shown great potential in lithium, sodium, and potassium secondary batteries.

SUMMARY OF THE INVENTION

The purpose of the present invention is to optimize a fluid seawater battery and a preparation method proposed for the problem of continuous energy supply in a specific marine environment. The present invention is easy to operate, environmentally friendly and recyclable.

The concrete technical scheme that realizes the object of the present invention is:

A fluid seawater battery and a preparation method, the method comprising the following specific steps:

Step 1: Selection and Preparation of Cathode

A1: Selection of coordination crystals

Prussian blue crystals and crystals with sodium ion storage sites are selected as coordination crystals, and the general molecular formula of the Prussian blue crystals is A _a M ^I _b M ^II _c [M ^III (CN) ₆ ] _d ·nH ₂ O; wherein, A is an alkali metal element, hydrogen ion or ammonium ion; M ^I , M ^II , M ^III are the same or different transition metal elements; a, b, c, d are values in [0,2] ; n is a value within [0,20]; the alkali metal element is Li, Na, K, Rb or Cs; the transition metal element is Fe, Co, Ni, Mn, Ti, Zn, Cr, Cu or In;

The crystals with sodium ion storage sites are: Na ₂ C ₆ O ₆ , Na ₄ Fe ₃ (PO ₄ ) ₂ (P ₂ O ₇ ), NaVO ₂ , NaCrO ₂ , NaMnFe ₂ (PO ₄ ) ₃ , Na ₃ Fe ₂ (PO ₄ ) ₃ , C ₂₄ H ₈ O ₆ , C ₆ Cl ₄ O ₂ , NaFePO ₄ , Na ₂ FeP ₂ O ₇ or NaMnO ₂ ;

A2: Preparation of Cathode Fluid

The preparation of cathode fluid adopts manual stirring, magnetic stirring or ultrasonic dispersion;

ⅰ) Manual stirring: Mix the coordination crystals and seawater in the container according to the proportion, the mass ratio of the coordination crystals and seawater is 1:10～8:10, use tools to stir for 5～50 minutes to become a uniform and continuous slurry, The cathode fluid can be obtained; wherein,

The tools are: glass rod, iron rod, aluminum alloy rod, magnesium alloy rod, scraper or electric mixer;

The seawater is natural seawater with at least 1ppm of dissolved oxygen and at least 0.35% of sodium chloride, seawater configured with sea salt, simulated seawater configured with sodium chloride or potassium chloride;

ii) Magnetic stirring: Mix the coordination crystals and seawater in the container according to the proportion, the mass ratio of the coordination crystals and seawater is 1:10～8:10, add a magnetic stirring bar, and use a magnetic stirring machine to drive the magnetic stirring bar to stir for 5～ After 50 minutes, a uniform and continuous slurry can be obtained, and the cathode fluid can be obtained; wherein,

The magnetic stirring bar is cylindrical, oval, cross, double-headed, triangular or octagonal, and the size is 5mm×5mm～500mm×500mm;

Described magnetic force stirrer is electric heating magnetic force stirring sleeve or flat plate magnetic force stirring machine;

ⅲ) Ultrasonic dispersion: Mix the coordination crystals and seawater in the container according to the proportion, the mass ratio of the coordination crystals and seawater is 1:10～8:10, use the ultrasonic disperser to carry out ultrasonic dispersion for 5～50 minutes, and it becomes uniform and continuous. , the cathode fluid can be obtained; wherein,

Described ultrasonic dispersing instrument is plug-in ultrasonic dispersing instrument, ultrasonic vibrator, ultrasonic cleaning instrument or ultrasonic vibration plate;

A3: Preparation of cathode

The prepared cathode fluid is guided by a pump, flows through the current collector, and is recirculated back to the container of the cathode fluid to obtain a fluid seawater battery cathode; wherein,

The pump is a centrifugal pump, a mixed flow pump, an axial flow pump, a vortex pump, a piston pump, a plunger pump, a diaphragm pump, a gear pump, a screw pump, a dicing pump, a jet pump, a water hammer pump or a vacuum pump;

The current collector is carbon cloth, carbon felt, metal titanium, metal copper or metal nickel;

The way of the current collector: flowing from the outside of the current collector or from the inside of the current collector.

Step 2: Anode Selection

Selecting metal magnesium, metal aluminum, metal zinc, mercury- and calcium-doped magnesium alloys, mercury- and calcium-doped aluminum alloys, mercury- and calcium-doped zinc alloys, or mercury- and calcium-doped magnesium-aluminum alloys as anodes;

Step 3: Electrolyte

Seawater is selected as the electrolyte to provide metal ions required in the power generation process and to balance the electrode polarization effect; the seawater is natural seawater with at least 1ppm of dissolved oxygen and at least 0.35% of sodium chloride, sea salt configuration seawater, sodium chloride or simulated seawater configured with potassium chloride;

Step 4: Generation of Constant Current

Put the cathode current collector and the anode into two containers separated by a diaphragm, connect the cathode current collector with a wire, and then connect the anode with a wire; immerse the anode with the electrolyte; turn on the pump and let the cathode fluid flow through Cathode current collector; can generate constant DC current;

Step 5: Cyclic Regeneration of Cathode-Coordination Crystals

When the metal ion storage sites in the cathode coordination crystal are fully occupied, the process of generating current will stop; stirring the cathode fluid, by contacting the cathode fluid with seawater or air, the coordination crystal is oxidized by the dissolved oxygen in the seawater or the oxygen in the air , while the coordination crystal loses electrons, the metal ions in the storage site are released; and then the cathode current collector is introduced through the pump to continue to generate constant direct current.

The Prussian blue compounds described in step 1 are: Fe ₄ [Fe(CN) ₆ ] ₃ (ferric ferrocyanide, Prussian blue, CAS No. 14038-43-8), Ni ₃ [Fe(CN) ₆ ] ₂ (nickel ferricyanide), Na ₂ Co[Fe(CN) ₆ ] (cobalt ferrocyanide), Ti[Fe(CN) ₆ ] (titanium ferrocyanide), Na ₂ Cu[Fe(CN) ₆ ] (copper ferrocyanide), Na ₂ Zn[Fe(CN) ₆ ] (zinc ferrocyanide).

The invention has the advantages of simple operation, environment-friendly materials and recyclable utilization. Among them, metals are mainly used to provide electrons in the process of power generation, and will eventually become ionic and dissolved in seawater; coordination crystals are mainly used to provide storage sites for metal ions. Compared with the prior art, the present invention can realize a seawater battery with improved energy density and recyclable use on the premise of ensuring simple process and environmental friendliness.

Description of drawings

1 is a schematic structural diagram of a fluid seawater battery of the present invention;

2 is a schematic side view of the cycle regeneration of the cathode material-coordination crystal of the fluid seawater battery of the present invention;

Fig. 3 is the galvanostatic discharge diagram of the seawater battery obtained in Example 1 of the present invention;

Fig. 4 is the galvanostatic discharge diagram of the seawater battery obtained in Example 2 of the present invention;

FIG. 5 is a galvanostatic discharge diagram of the seawater battery prepared in Example 3 of the present invention.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 , the structure of the seawater battery of the present invention is shown in the figure. The prepared coordination crystal 1 is mixed with natural seawater 2 to form a cathode fluid, which is placed in a 1 L beaker. The other side was placed in another beaker with natural seawater 2 as the electrolyte. In the flow electrolysis cell 5, a carbon felt 7 is used as a cathode current collector, and a metal aluminum sheet 8 with an industrial designation 1A99 is used as an anode electrode, and is separated by a cation exchange membrane 6 with a type CMI 7000. The carbon felt 7 is drawn out with copper wires and connected to the cathode of the load 10 such as a small light bulb, and the metal aluminum sheet 8 of industrial grade 1A99 is connected to the anode of the load 10 with copper wires. Then use the pump 3 to introduce the cathode fluid from the liquid inlet and outlet 4 through the silicone tube 9, and then flow back into the beaker through another liquid inlet and outlet on the same side to form a cycle. Use pump 3 to introduce anolyte from the liquid inlet and outlet through a silicone tube, and then flow back into the beaker through another liquid inlet and outlet on the same side to form a cycle. It constitutes the seawater battery of the present invention.

Referring to FIG. 2 , the schematic diagram of the cycle regeneration of the cathode coordination crystal of the seawater battery of the present invention, when the metal ion storage sites of the coordination crystal 1 are all occupied, the current generation process will stop. In the beaker storing the cathode fluid, the coordination crystal 1 is oxidized by the dissolved oxygen in the seawater 2 or the oxygen in the air, so that the coordination crystal 1 loses electrons and releases the metal ions in the storage site; the oxygen is reduced to hydrogen Oxygen is dissolved into seawater, and this process generally takes 1 day.

Example 1

hand stirring

The cathode material selected in this example is a Prussian blue coordination crystal with the molecular formula Fe ₄ [Fe(CN) ₆ ] ₃ ; the anode material is industrial pure aluminum with a license plate of 1A99; and the electrolyte is natural seawater.

Step 1: Preparation of Prussian Blue Coordination Crystal

Dissolve 16.7 g of ferrous chloride hydrate (FeCl ₂ ·6H ₂ O) and 20 g of sodium citrate dihydrate (HOC(COOH)(CH ₂ COONa) ₂ ·1.5H ₂ O) in 2.5 L of deionized water A transparent and clear solution A was formed; 14.5 g of sodium ferrocyanide (Na ₄ [Fe(CN) ₆ ]) was dissolved in 2.5 L of deionized water to form a transparent and clear solution B, and the solution A and solution B were uniformly mixed at room temperature to obtain The gray-white turbid liquid was reacted at room temperature (25°C) for 24 hours to obtain a dark blue Prussian blue coordination crystal solution. The obtained Prussian blue coordination crystal solution was centrifuged at 10,000 rpm to obtain a Prussian blue coordination crystal solid; a , put the obtained Prussian blue coordination crystalline solid into 20 ml of industrial alcohol and disperse by ultrasonic for 10 min, and then centrifuge at a speed of 8000 rpm to obtain the Prussian blue coordination crystalline solid; b, the Prussian blue coordination crystalline solid obtained by a Put 20ml of deionized water into 20ml of deionized water for ultrasonic dispersion for 10min, and then centrifuge at 10000rpm to obtain a Prussian blue coordination crystal solid; repeat steps a and b three times. The final obtained solid was placed at room temperature, dried in vacuum for 20 h, and the degree of vacuum was less than 0.1 Pa;

Step 2: Preparation of Cathode Fluid for Seawater Batteries

Take 50 g of the Prussian blue coordination crystal solid in step 1 and 500 ml of natural seawater into a beaker with a volume of 1 L, and stir with an electric mixer for 15 minutes to form a uniform and continuous slurry. The obtained product can be used as the cathode fluid of seawater battery;

Step 3: Preparation of Seawater Battery Cathode Current Collector

The carbon felt is cut into a block of 1.5 cm×1.5 cm×1 cm, which can be used as the cathode current collector of the seawater battery.

Step 4: Preparation of Seawater Battery Anode

Select industrial pure aluminum with a license plate of 1A99, and divide it into aluminum sheets with a size of 2.5 cm × 2.5 cm × 0.5 cm, which can be used as the anode of the seawater battery.

Step 5: Assembly of Seawater Battery and Generation of Constant Current

The carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 were respectively placed in two electrolytic cells separated by cation exchange membranes of type CMI 7000. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires respectively and connected to the two poles of the electrical appliance, and a stable direct current can be output.

Fig. 3 is the galvanostatic discharge diagram of the fluid seawater battery of the present embodiment, and the test condition is that the carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 are respectively placed in a cation exchange membrane with a model of CMI 7000 to separate in the two electrolytic cells. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires, respectively, and are connected to the blue battery test system in constant current mode to discharge at a current of 5 mA, and the voltage-time relationship diagram shown in Figure 3 can be obtained.

In this embodiment, when the seawater electrolyte and the cathode fluid are respectively passed into two electrolytic cells separated by a cation exchange membrane with a model of CMI 7000, and the aluminum sheet and the carbon felt current collector are immersed, the 1A99 aluminum alloy is relatively The low redox potential will drive the electrons to move to the carbon felt end, and finally transfer them to the cathode fluid. The Prussian blue coordination crystal accepts electrons and absorbs a cation in seawater at the same time to form a Prussian white coordination crystal. The metal aluminum will become The ionic form dissolves in seawater, and an electric current is generated due to the flow of electrons. When the cathode fluid comes into contact with the dissolved oxygen in seawater or oxygen in the air after being drawn out of the electrolytic cell, it will oxidize the Prussian white coordination crystal and release a cation at the same time, which will restore to the Prussian blue coordination crystal. Cycle regeneration. This reciprocation can provide a stable current. The whole process is simple and easy to implement, and is friendly to the seawater environment without pollution.

Example 2

Magnetic stirring

The cathode material selected in this embodiment is a Prussian blue coordination crystal, and its molecular formula is Fe ₄ [Fe(CN) ₆ ] ₃ ; the anode material is industrial pure aluminum with a license plate of 1A99; and the electrolyte is seawater prepared with sea salt.

Step 1: Preparation of Prussian Blue Coordination Crystal

Dissolve 16.7 g of ferrous chloride hydrate (FeCl ₂ ·6H ₂ O) and 20 g of sodium citrate dihydrate (HOC(COOH)(CH ₂ COONa) ₂ ·1.5H ₂ O) in 2.5 L of deionized water A transparent and clear solution A was formed; 14.5 g of sodium ferrocyanide (Na ₄ [Fe(CN) ₆ ]) was dissolved in 2.5 L of deionized water to form a transparent and clear solution B, and the solution A and solution B were uniformly mixed at room temperature to obtain The gray-white turbid liquid was reacted at room temperature (25°C) for 24 hours to obtain a dark blue Prussian blue coordination crystal solution. The obtained Prussian blue coordination crystal solution was centrifuged at 10,000 rpm to obtain a Prussian blue coordination crystal solid; a , put the obtained Prussian blue coordination crystalline solid into 20 ml of industrial alcohol and disperse by ultrasonic for 10 min, and then centrifuge at a speed of 8000 rpm to obtain the Prussian blue coordination crystalline solid; b, the Prussian blue coordination crystalline solid obtained by a Put 20ml of deionized water into 20ml of deionized water for ultrasonic dispersion for 10min, and then centrifuge at 10000rpm to obtain a Prussian blue coordination crystal solid; repeat steps a and b three times. The final obtained solid was placed at room temperature, dried in vacuum for 20 h, and the degree of vacuum was less than 0.1 Pa;

Step 2: Preparation of Cathode Fluid for Seawater Batteries

Take 50 g of the Prussian blue coordination crystal solid in step 1 and 500 ml of natural seawater into a beaker with a volume of 1 L, put a cylindrical magnetic stirrer with a size of 120 mm × 10 mm, and stir with a magnetic stirrer at 400 rpm. Stir at a speed of one minute for 30 minutes to form a uniform and continuous slurry. The obtained product can be used as the cathode fluid of seawater battery;

Step 3: Preparation of Seawater Battery Cathode Current Collector

The carbon felt is cut into a block of 2 cm × 2 cm × 1 cm, which can be used as the cathode current collector of the seawater battery.

Step 4: Preparation of Seawater Battery Anode

Select industrial pure aluminum with a license plate of 1A99, and divide it into aluminum sheets with a size of 1 cm × 1 cm × 0.5 cm, which can be used as the anode of the seawater battery.

Step 5: Assembly of Seawater Battery and Generation of Constant Current

The carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 were respectively placed in two electrolytic cells separated by cation exchange membranes of type CMI 7000. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires respectively and connected to the two poles of the electrical appliance, and a stable direct current can be output.

Fig. 4 is the galvanostatic discharge diagram of the fluid seawater battery of the present embodiment, and the test conditions are that the carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 are placed in separate cation exchange membranes with a model of CMI 7000. in the two electrolytic cells. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires, respectively, and are connected to the blue battery test system in constant current mode to discharge at a current of 5 mA, and the voltage-time relationship diagram shown in Figure 4 can be obtained.

In this embodiment, when the seawater electrolyte and the cathode fluid are respectively passed into two electrolytic cells separated by a cation exchange membrane with a model of CMI 7000, and the aluminum sheet and the carbon felt current collector are immersed, the 1A99 aluminum alloy is relatively The low redox potential will drive the electrons to move to the carbon felt end, and finally transfer them to the cathode fluid. The Prussian blue coordination crystal accepts electrons and absorbs a cation in seawater at the same time to form a Prussian white coordination crystal. The metal aluminum will become The ionic form dissolves in seawater, and an electric current is generated due to the flow of electrons. When the cathode fluid comes into contact with the dissolved oxygen in seawater or oxygen in the air after being drawn out of the electrolytic cell, it will oxidize the Prussian white coordination crystal and release a cation at the same time, which will restore to the Prussian blue coordination crystal. Cycle regeneration. This reciprocation can provide a stable current. The whole process is simple and easy to implement, and is friendly to the seawater environment without pollution.

Example 3

Ultrasonic dispersion

The cathode material selected in this embodiment is a Prussian blue coordination crystal, and its molecular formula is Fe ₄ [Fe(CN) ₆ ] ₃ ; the anode material is industrial pure aluminum with a license plate of 1A99; and the electrolyte is seawater prepared with sea salt.

Step 1: Preparation of Prussian Blue Coordination Crystal

Dissolve 16.7 g of ferrous chloride hydrate (FeCl ₂ ·6H ₂ O) and 20 g of sodium citrate dihydrate (HOC(COOH)(CH ₂ COONa) ₂ ·1.5H ₂ O) in 2.5 L of deionized water A transparent and clear solution A was formed; 14.5 g of sodium ferrocyanide (Na ₄ [Fe(CN) ₆ ]) was dissolved in 2.5 L of deionized water to form a transparent and clear solution B, and the solution A and solution B were uniformly mixed at room temperature to obtain The gray-white turbid liquid was reacted at room temperature (25°C) for 24 hours to obtain a dark blue Prussian blue coordination crystal solution. The obtained Prussian blue coordination crystal solution was centrifuged at 10,000 rpm to obtain a Prussian blue coordination crystal solid; a , put the obtained Prussian blue coordination crystalline solid into 20 ml of industrial alcohol and disperse by ultrasonic for 10 min, and then centrifuge at a speed of 8000 rpm to obtain the Prussian blue coordination crystalline solid; b, the Prussian blue coordination crystalline solid obtained by a Put 20ml of deionized water into 20ml of deionized water for ultrasonic dispersion for 10min, and then centrifuge at 10000rpm to obtain a Prussian blue coordination crystal solid; repeat steps a and b three times. The final obtained solid was placed at room temperature, dried in vacuum for 20 h, and the degree of vacuum was less than 0.1 Pa;

Step 2: Preparation of Cathode Fluid for Seawater Batteries

Take 50 g of the Prussian blue coordination crystal solid in step 1 and 500 ml of natural seawater into a beaker with a volume of 1 L, put it into an ultrasonic cleaner with a power of 50 kHz, and continuously ultrasonicate for 30 minutes to become a uniform and continuous slurry . The obtained product can be used as the cathode fluid of seawater battery;

Step 3: Preparation of Seawater Battery Cathode Current Collector

The carbon felt is cut into a block of 1.5 cm×1.5 cm×1 cm, which can be used as the cathode current collector of the seawater battery.

Step 4: Preparation of Seawater Battery Anode

Select industrial pure aluminum with a license plate of 1A99, and divide it into aluminum sheets with a size of 3 cm × 3 cm × 0.5 cm, which can be used as the anode of the seawater battery.

Step 5: Assembly of Seawater Battery and Generation of Constant Current

The carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 were respectively placed in two electrolytic cells separated by cation exchange membranes of type CMI 7000. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires respectively and connected to the two poles of the electrical appliance, and a stable direct current can be output.

Fig. 5 is the galvanostatic discharge diagram of the fluid seawater battery of the present embodiment, and the test conditions are that the carbon felt obtained in step 3 and the metal aluminum sheet obtained in step 4 are respectively placed in a cation exchange membrane with a model of CMI 7000 to separate in the two electrolytic cells. The seawater electrolyte and cathodic fluid were placed in two 1 L beakers, respectively, and the seawater electrolyte and cathodic fluid were introduced into the anolyte and catholyte cells with a peristaltic pump and a silicone tube, respectively. The cathode and anode are drawn out with copper wires, respectively, and are connected to the blue battery test system in constant current mode to discharge at a current of 5 mA, and the voltage-time relationship diagram shown in Figure 5 can be obtained.

In this embodiment, when the seawater electrolyte and the cathode fluid are respectively passed into two electrolytic cells separated by a cation exchange membrane with a model of CMI 7000, and the aluminum sheet and the carbon felt current collector are immersed, the 1A99 aluminum alloy is relatively The low redox potential will drive the electrons to move to the carbon felt end, and finally transfer them to the cathode fluid. The Prussian blue coordination crystal accepts electrons and absorbs a cation in seawater at the same time to form a Prussian white coordination crystal. The metal aluminum will become The ionic form dissolves in seawater, and an electric current is generated due to the flow of electrons. When the cathode fluid comes into contact with the dissolved oxygen in seawater or oxygen in the air after being drawn out of the electrolytic cell, it will oxidize the Prussian white coordination crystal and release a cation at the same time, which will restore to the Prussian blue coordination crystal. Cycle regeneration. This reciprocation can provide a stable current. The whole process is simple and easy to implement, and is friendly to the seawater environment without pollution.

Claims (3)

1. The preparation method of the fluid seawater battery is characterized by comprising the following specific steps of:

step 1: selection and preparation of cathode

A1: selection of coordination crystals

Selecting Prussian blue crystals and crystals with sodium ion storage sites as coordination crystals, wherein the molecular general formula of the Prussian blue crystals is A_aM^Ⅰ _bM^Ⅱ _c[M^Ⅲ(CN)₆]_d·nH₂O; wherein A is an alkali metal element, a hydrogen ion or an ammonium ion; m^Ⅰ、M^Ⅱ、M^ⅢAre the same or different transition metal elements; a. b, c, d are [0,2 ]]The value of (a); n is [0,20 ]]The value of (a); the alkali metal element is Li, Na, K, Rb or Cs; the transition metal element is Fe, Co, Ni, Mn, Ti, Zn, Cr, Cu or In;

the crystal with sodium ion storage sites is: na (Na)₂C₆O₆、Na₄Fe₃(PO₄)₂(P₂O₇)、NaVO₂、NaCrO₂、NaMnFe₂(PO₄)₃、Na₃Fe₂(PO₄)₃、C₂₄H₈O₆、C₆Cl₄O₂、NaFePO₄、Na₂FeP₂O₇Or NaMnO₂；

A2: preparation of cathode fluids

Preparing the cathode fluid by adopting a manual stirring, magnetic stirring or ultrasonic dispersion mode;

i) manual stirring: mixing the coordination crystals and the seawater in a container according to a mass ratio of 1: 10-8: 10, and stirring for 5-50 minutes by using a tool to form uniform and continuous slurry, so as to obtain the cathode fluid; wherein,

the tool is as follows: glass rods, iron rods, aluminum alloy rods, magnesium alloy rods, scrapers or electric mixers;

the seawater is natural seawater with dissolved oxygen of at least 1ppm and sodium chloride of at least 0.35%, seawater prepared from sea salt or simulated seawater prepared from sodium chloride or potassium chloride;

ii) magnetic stirring: mixing the coordination crystals and the seawater in a container according to a mass ratio of 1: 10-8: 10, adding a magnetic stirrer, and driving the magnetic stirrer to stir for 5-50 minutes by using a magnetic stirrer to form uniform and continuous slurry, thus obtaining the cathode fluid; wherein,

the magnetic stirrer is cylindrical, elliptical, cross-shaped, double-ended, triangular or octagonal and has the size of 5mm multiplied by 5 mm-500 mm multiplied by 500 mm;

the magnetic stirrer is an electric heating magnetic stirring sleeve or a flat plate type magnetic stirrer;

iii) ultrasonic dispersion: mixing the coordination crystals and seawater in a container according to a mass ratio of 1: 10-8: 10, and performing ultrasonic dispersion for 5-50 minutes by using an ultrasonic disperser to obtain uniform and continuous slurry, so as to obtain the cathode fluid; wherein,

the ultrasonic dispersion instrument is an inserted ultrasonic dispersion instrument, an ultrasonic vibrator, an ultrasonic cleaning instrument or an ultrasonic vibration plate;

a3: preparation of the cathode

Guiding the prepared cathode fluid by a pump, flowing the cathode fluid through a current collector, and then circularly flowing the cathode fluid back to a container of the cathode fluid to obtain a fluid seawater battery cathode; wherein,

the pump is a centrifugal pump, a mixed flow pump, an axial flow pump, a vortex pump, a piston pump, a plunger pump, a diaphragm pump, a gear pump, a screw pump, a scribing pump, an injection pump, a hydraulic ram or a vacuum pump;

the current collector is carbon cloth, carbon felt, metal titanium, metal copper or metal nickel;

the manner of flow through the current collector: flow from the outside of the current collector or from the inside of the current collector;

step 2: selection of anodes

Selecting metal magnesium, metal aluminum, metal zinc, mercury and calcium doped magnesium alloy, mercury and calcium doped aluminum alloy, mercury and calcium doped zinc alloy or mercury and calcium doped magnesium aluminum alloy as an anode;

and step 3: electrolyte solution

Seawater is selected as electrolyte for providing metal ions required in the power generation process and balancing electrode polarization effect; the seawater is natural seawater with dissolved oxygen of at least 1ppm and sodium chloride of at least 0.35%, seawater prepared from sea salt or simulated seawater prepared from sodium chloride or potassium chloride;

and 4, step 4: generation of constant current

Respectively putting the cathode current collector and the anode into two containers separated by a diaphragm, connecting the cathode current collector by a lead, and connecting the anode by the lead; immersing the anode with an electrolyte; opening the pump to flow the cathode fluid through the cathode current collector; constant direct current can be generated;

the diaphragm is: a cation exchange membrane, an anion exchange membrane, or a nonwoven fabric diaphragm;

and 5: cyclic regeneration of cathode-coordination crystals

When the metal ion storage sites in the cathode coordination crystal are completely occupied, the process of generating current is stopped; stirring the cathode fluid, and contacting the cathode fluid with seawater or air to oxidize the coordination crystals by using dissolved oxygen in the seawater or oxygen in the air, so that the coordination crystals lose electrons and release metal ions in the storage sites; then the cathode current collector is led in by a pump to continuously generate constant direct current.

2. The method for manufacturing a fluid seawater battery according to claim 1, wherein the prussian blue-based crystal is: fe₄[Fe(CN)₆]₃、NaFe[Fe(CN)₆]、Fe[Fe(CN)₆]、NaMn[Fe(CN)₆]、Na₂Mn[Fe(CN)₆]、NaMn[Fe(CN)₆]、 Ni₃[Fe(CN)₆]₂、Na₂Ni[Fe(CN)₆]、Na₂Co[Fe(CN)₆]、NaTi[Fe(CN)₆]、Na₂Cu[Fe(CN)₆]Or Na₂Zn[Fe(CN)₆]。

3. A fluid seawater battery made by the method of claim 1.

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