Preparation method of a high specific energy Zn / AgO small button secondary battery

Abstract

The present invention discloses a preparation method of a high specific energy Zn / AgO small button secondary battery. First, the positive electrode material is synthesized by a chemical method, then an alkaline electrolyte with a low hydrogen evolution amount is prepared, and finally a mercury-free inhibitor zinc paste negative electrode is used. The AG3 type zinc-silver button battery is assembled using the above positive electrode, zinc paste negative electrode, alkaline electrolyte and separator. The Zn / AgO small button secondary battery prepared according to the method provided by the present invention has the advantages of high specific energy, long cycle life and simple preparation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous batteries, and particularly relates to a preparation method of a Zn / AgO small button-shaped secondary battery with high specific energy and wide temperature range. Background Art

[0002] In the field of small Zn / AgO batteries, the battery working performance and service life are mainly related to the stability and resistivity of the positive electrode, the corrosion resistance and hydrogen evolution performance of the negative electrode, and the silver resistance, liquid retention amount and dendrite resistance of the separator: 1) AgO has poor thermodynamic stability and is easy to decompose. The formation of Ag2O during charge and discharge causes a significant decrease in the conductivity of the positive electrode; 2) The reaction of the alkaline electrolyte with the zinc negative electrode causes corrosion of the negative electrode and hydrogen evolution at the same time; 3) The formation of dendrites on the positive and negative electrodes pierces the separator, causing battery short circuit. The migration of silver ions causes micro short circuit of the battery, and the low liquid retention amount of the separator leads to a decrease in the battery cycle performance.

[0003] Currently, in the field of small batteries, the process of lithium-ion battery products is complex and the yield is low, and it cannot meet the use requirements in ultra-low temperature environments. The preparation process of small Zn / AgO batteries is simple, can meet the use in a wide temperature range, and has a large market demand. Summary of the Invention

[0004] In order to simplify the manufacturing process of small batteries and improve the cycle performance of Zn / AgO, the present invention provides a preparation method of a high specific energy Zn / AgO small button-shaped secondary battery.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a preparation method of a high specific energy Zn / AgO small button-shaped secondary battery, comprising the following steps:

[0006] (1) Synthesize the positive electrode material by a chemical method: use dispersed silver powder as the precursor of the electrode material, oxidize the precursor to Ag / AgO composite material with alkaline sodium persulfate solution as the oxidant, and perform surface modification on the Ag / AgO material with an alkaline PbS dispersion base solution having the same concentration as the alkaline sodium persulfate solution to obtain a spherical Ag / AgO / AgPbO composite positive electrode material. Use a tablet press to press the composite positive electrode material into a round AgO ultra-thick positive electrode without additives by a die pressing method;

[0007] (2) Prepare an alkaline electrolyte with low hydrogen evolution amount: add potassium fluoride (KF), potassium perfluorobutanesulfonate (C 4 F 9 SO 3 K), zinc trifluoromethanesulfonate ((CF 3 SO 3 ) 2 Zn) and zinc laurate as corrosion inhibitors for the negative electrode of zinc-silver batteries to prepare an alkaline electrolyte with a concentration of 4-10 mol / L;

[0008] (3) Preparation of mercury-free inhibitor zinc paste anode: Using PTFE emulsion as binder, elemental zinc powder (Zn) and zinc oxide (ZnO) as active substances, indium oxide (In 2 O 3 ), indium hydroxide (In(OH) 3 ), lead monoxide (PbO), elemental lead powder (Pb), sodium stannate (Na 2 SnO 3 ), or one or more of them as mercury-free inhibitors are mixed evenly in a certain proportion. Heat the PTFE emulsion in the mixed powder, add a certain amount of ethanol, extrude and rod-form repeatedly to form zinc paste, and finally complete the preparation of the zinc paste anode through vacuum drying;

[0009] (4) Use an olefin fiber grafted with sodium styrene sulfonate composite diaphragm with hydrophilic groups as the battery positive electrode diaphragm, use a triacetate cellulose composite membrane as the silver-blocking diaphragm in the middle layer of the zinc-silver battery, and use an olefin fiber grafted with hydroxyl composite diaphragm as the negative electrode diaphragm. The non-grafted surfaces of the positive and negative diaphragms correspond to the electrode sheets. The olefin fiber base material of the diaphragm can be PP or PE to complete the encapsulation of the battery.

[0010] In the preparation method of the high specific energy Zn / AgO small button-shaped secondary battery described above, the silver powder in step (1) is spherical particles with a particle size of 1 - 15 μm, and the silver powder accounts for 3 - 30% of the mass of the precursor solution.

[0011] In the preparation method of the high specific energy Zn / AgO small button-shaped secondary battery described above, in step (1), first prepare a highly dispersed aqueous solution with a mass content of elemental silver powder of 5 - 30%, then prepare a sodium persulfate alkaline solution with a KOH concentration of 2 - 8 mol / L and a sodium persulfate concentration of 0.5 - 5 mol / L. Heat the two solutions to 50 - 85 °C and mix them evenly, keep heating and stirring, react for 60 - 120 min, and finally add a PbS alkaline solution with a mass ratio of 3 - 10%, react for 15 - 45 min. After the mixed solution cools, filter, wash, and dry to obtain the Ag / AgO / AgPbO composite positive electrode material.

[0012] In the preparation method of the high specific energy Zn / AgO small button-shaped secondary battery described above, the elemental silver powder precursor solution is dispersed in an aqueous solution containing less than 3% of PVA and PVP dispersants. The elemental silver powder and sodium persulfate are in a chemical reaction molar ratio, and sodium persulfate is 50 - 200% in excess of the elemental silver powder.

[0013] The preparation method of a high specific energy Zn / AgO small button secondary battery, in step (1), the diameter of the AgO electrode sheet is 5-15 mm, the thickness is 0.5-4 mm, preferably the diameter is 6.4-7.1 mm, the thickness is 1-2 mm, and the density is 1.2-2.6 g / ml.

[0014] The preparation method of a high specific energy Zn / AgO small button secondary battery, in step (2), the zinc contents of potassium fluoride (KF), potassium perfluorobutanesulfonate (C 4 F 9 SO 3 K), zinc trifluoromethanesulfonate ((CF 3 SO 3 ) 2 Zn) and lauric acid are 0.5-1.50 mol / L, 5-30 mmol / L, 20-100 mmol / L and 10-100 mmol / L respectively.

[0015] The preparation method of a high specific energy Zn / AgO small button secondary battery, in step (3), the content of the active substance is 75-95%, the content of the corrosion inhibitor is 3-10%, and the content of the binder is 2.5-5%; among them, the vacuum drying temperature of the zinc paste is 60-100 °C, the time is 8-24 h, after drying is completed, turn off the heating belt, cool to room temperature and then take out the negative electrode; the density of the zinc paste is 0.6-1.5 g / ml, the thickness of the zinc paste negative electrode is 1-10 mm, preferably 0.8-1.6 mm.

[0016] The preparation method of a high specific energy Zn / AgO small button secondary battery, in step (3), the proportions of the components in the mixed powder of elemental zinc powder (Zn), zinc oxide (ZnO), indium oxide (In 2 O 3 ), indium hydroxide (In(OH) 3 ), lead monoxide (PbO), elemental lead powder (Pb) and sodium stannate (Na 2 SnO 3 ) are 60-90%, 3-20%, 0.3-2%, 0.5-2%, 1-5%, 1-5% and 0.2-1.5% respectively.

[0017] The preparation method of a high specific energy Zn / AgO small button secondary battery, in step (4), place the positive electrode sheet in the positive electrode shell of the AG3 battery, sequentially put in the grafted sodium styrenesulfonate composite diaphragm, the triacetate hydrated cellulose composite membrane and the olefin fiber grafted hydroxyl composite diaphragm, add 5-25 μL of electrolyte and then let it stand for 2 h, use the negative electrode shell of the AG3 battery to buckle reversely on the zinc paste, press the negative electrode shell so that the zinc paste is directly embedded in the positive electrode shell of the battery, then drop 1-10 μL of electrolyte and let it stand for 2 h, and use the battery packaging equipment to complete the packaging of the button battery.

[0018] The preparation method of a high specific energy Zn / AgO small button secondary battery, wherein the thickness of the positive electrode separator is 30-120 μm, and the liquid absorption capacity is greater than 200%; the thickness of the silver-blocking separator is 30-90 μm; the thickness of the negative electrode separator is 30-120 μm, and the liquid absorption capacity is greater than 150%.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention mainly uses a spherical silver powder dispersion solution as a precursor, and chemically synthesizes an Ag / AgO / AgPbO composite positive electrode material with a spherical three-layer sandwich structure; uses an inorganic corrosion inhibitor and a perfluoro-hydrophilic group alkane organic corrosion inhibitor to prepare a zinc-silver battery electrolyte with a low hydrogen evolution amount; compositely uses a single-sided radiation grafting separator and a triacetate cellulose composite membrane; adopts a one-step compression molding method to prepare an AgO ultra-thick positive electrode sheet without additives, uses a membrane rod method to prepare a zinc paste negative electrode with a corrosion inhibitor, and finally assembles and completes an AG3 button battery.

[0021] The Ag / AgO / AgPbO composite positive electrode material synthesized by a chemical method improves the stability of AgO, enhances the matching between the positive electrode material and the electrolyte, and essentially solves the problem of the decrease in conductivity caused by the formation of Ag 2 O during the charge and discharge process.

[0022] Potassium perfluorobutanesulfonate (C 4 F 9 SO 3 K), zinc trifluoromethanesulfonate ((CF 3 SO 3 ) 2 Zn), zinc laurate organic corrosion inhibitor and indium hydroxide (In(OH) 3 ), lead monoxide (PbO) and other inorganic corrosion inhibitors are used in combination to greatly reduce the corrosion of the zinc negative electrode and the generation of hydrogen during the use of the battery, improve the battery cycle performance, and solve the problem of seal failure caused by a large amount of gas generation in the battery.

[0023] A radiation grafting composite separator with a hydrophilic group is used as the positive and negative electrode separators of the battery, and a triacetate cellulose composite membrane is used as the silver-blocking separator of the zinc-silver battery. The composite use of the single-sided radiation grafting separator and the triacetate cellulose composite membrane ensures the anti-metal dendrite and silver-blocking capabilities of the separator, while improving the wettability of the separator and the electrolyte retention amount.

[0024] The AG3 type Zn / AgO button battery prepared according to the method of the present invention has a rated capacity of 32 mA, a maximum discharge capacity of 45 mA, an average discharge voltage of 1.67 V, a battery energy density higher than 130 Wh / Kg, and a capacity retention rate of 100% after 100 cycles. Brief Description of the Drawings

[0025] Figure 1 This is the XRD scanning pattern of the Ag / AgO / AgPbO composite cathode material of the present invention;

[0026] Figure 2 This is the SEM photograph of the spherical Ag / AgO / AgPbO composite cathode material of the present invention;

[0027] Figure 3 This is the charge-discharge curve of the AG3 button cell of the present invention;

[0028] Figure 4 This is the cycle performance graph of the AG3 button cell of the present invention. Detailed Description of the Invention

[0029] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0030] Example 1

[0031] Refer to Figures 1 to 4 As shown, a preparation method of a high specific energy Zn / AgO small button secondary battery disclosed by the present invention includes the following steps:

[0032] Synthesize the cathode material by a chemical method.

[0033] Using spherical particulate silver powder with a particle size of 1-15 μm as the precursor of the electrode material, the silver powder accounts for 3-30% of the mass of the precursor solution, and using an alkaline sodium persulfate solution as the oxidant to oxidize the precursor into an Ag / AgO composite material. First, prepare a highly dispersed aqueous solution with a mass content of elemental silver powder of 5-30%, then prepare a sodium persulfate alkaline solution with a KOH concentration of 2-8 mol / L and a sodium persulfate concentration of 0.5-5 mol / L. Heat the two solutions to 50-85 °C and then mix them evenly, keep heating and stirring, the reaction time is 60-120 min, and finally add a PbS alkaline solution with a mass ratio of 3-10%, react for 15-45 min, and after the mixed solution cools, filter, wash, and dry to obtain the Ag / AgO / AgPbO composite cathode material. Among them, the elemental silver powder precursor solution is dispersed in an aqueous solution containing a dispersant of PVA and PVP below 3%, and the elemental silver powder and sodium persulfate are in a chemical reaction molar ratio, and sodium persulfate is 50-200% in excess of the elemental silver powder. The diameter of the AgO electrode sheet is 5-15 mm, the thickness is 0.5-4 mm, preferably the diameter is 6.4-7.1 mm, the thickness is 1-2 mm, and the density is 1.2-2.6 g / ml.

[0034] (2) Prepare an alkaline electrolyte with a low hydrogen evolution amount.

[0035] Add potassium fluoride (KF), potassium perfluorobutanesulfonate (C 4F 9 SO 3 K), zinc trifluoromethanesulfonate ((CF 3 SO 3 ) 2 Zn) and zinc laurate are used as corrosion inhibitors for the negative electrode of a zinc-silver battery to prepare an alkaline electrolyte with a concentration of 4 to 10 mol / L; potassium fluoride (KF), potassium perfluorobutanesulfonate (C 4 F 9 SO 3 K), zinc trifluoromethanesulfonate ((CF 3 SO 3 ) 2 Zn) and the zinc contents of lauric acid are 0.5 to 1.50 mol / L, 5 to 30 mmol / L, 20 to 100 mmol / L, and 10 - 100 mmol / L, respectively.

[0036] (3) Prepare a mercury-free corrosion inhibitor zinc paste negative electrode.

[0037] Use PTFE emulsion as a binder, use elemental zinc powder (Zn), zinc oxide (ZnO) as active substances, and use indium oxide (In 2 O 3 ), indium hydroxide (In(OH) 3 ), lead monoxide (PbO), elemental lead powder (Pb), sodium stannate (Na 2 SnO 3 ) or one or more of them as a mercury-free corrosion inhibitor and mix them evenly in a certain proportion. Heat the PTFE emulsion in the mixed powder, add a certain amount of ethanol, extrude and roll it repeatedly to form a zinc paste, and finally complete the preparation of the zinc paste negative electrode through vacuum drying; among them, the content of the active substance is 75 - 95%, the content of the corrosion inhibitor is 3 - 10%, and the content of the binder is 2.5 - 5%; among them, the vacuum drying temperature of the zinc paste is 60 - 100 °C, the time is 8 - 24 h, after drying is completed, turn off the heating belt and cool to room temperature, and then take out the negative electrode; the density of the zinc paste is 0.6 - 1.5 g / ml, the thickness of the zinc paste negative electrode is 1 - 10 mm, preferably 0.8 - 1.6 mm. Among them, the proportions of each component in the elemental zinc powder (Zn), zinc oxide (ZnO), indium oxide (In 2 O 3 ), indium hydroxide (In(OH) 3 ), lead monoxide (PbO), elemental lead powder (Pb) and sodium stannate (Na 2 SnO 3 ) are 60 - 90%, 3 - 20%, 0.3 - 2%, 0.5 - 2%, 1 - 5%, 1 - 5% and 0.2 - 1.5%, respectively.

[0038] (4) An olefin fiber grafted with a hydrophilic group and grafted with sodium styrene sulfonate composite diaphragm is used as the positive electrode diaphragm of the battery. A cellulose triacetate hydrated composite membrane is used as the silver-blocking diaphragm in the middle layer of the zinc-silver battery. An olefin fiber grafted with hydroxyl groups composite diaphragm is used as the negative electrode diaphragm. The non-grafted surfaces of the positive and negative diaphragms correspond to the electrode plates. The olefin fiber base material of the diaphragm can be PP or PE.

[0039] Place the positive electrode plate in the positive electrode case of the AG3 battery. Sequentially place the grafted sodium styrene sulfonate composite diaphragm, the cellulose triacetate hydrated composite membrane, and the olefin fiber grafted with hydroxyl groups composite diaphragm. After adding 5 - 25 μL of electrolyte, let it stand for 2 h. Use the negative electrode case of the AG3 battery to buckle it reversely on the zinc paste. Press the zinc paste of the negative electrode case directly into the positive electrode case of the battery. Then, after dropping 1 - 10 μL of electrolyte and letting it stand for 2 h, use the battery packaging equipment to complete the packaging of the button battery; the thickness of the positive electrode diaphragm is 30 - 120 μm, and the liquid absorption capacity is greater than 200%; the thickness of the silver-blocking diaphragm is 30 - 90 μm; the thickness of the negative electrode diaphragm is 30 - 120 μm, and the liquid absorption capacity is greater than 150%.

[0040] The AG3 type zinc-silver button battery assembled with the above positive electrode, zinc paste negative electrode, alkaline electrolyte, and diaphragm has a high energy density and excellent cycling performance. The Zn / AgO small button secondary battery prepared by the method of the present invention has the advantages of high specific energy, long cycle life, and simple preparation process.

[0041] Example 2

[0042] The difference from Example 1 is that in this example, an oxidant solution with a KOH concentration of 2 - 8 mol / L and a sodium persulfate concentration of 0.5 - 5 mol / L is first prepared; 200 mL of the elemental silver powder dispersion liquid and 300 mL of the sodium persulfate alkaline solution are respectively heated to 50 - 85 °C, poured into a 1 L beaker, and stirred at a rotation speed of 150 - 450 rad / min. At the same time, the mixed solution is heated to keep the solution temperature in the range of 55 - 85 °C. The stirring and heating time lasts for 60 - 120 min. After the mixed solution is cooled, it is filtered, washed, and dried to obtain a spherical Ag / AgO composite material.

[0043] Take 5 - 20 Ag / AgO composite materials and add them to 100 mL of a lead sulfide alkaline solution with a mass ratio of 3 - 10%. React at 65 - 75 °C for 15 - 45 min. After the mixed solution is cooled, it is filtered, washed, and dried to obtain a spherical Ag / AgO / AgPbO composite positive electrode material.

[0044] Weigh 0.15 - 0.5 g of the composite cathode material of Ag / AgO / AgPbO and pour it into a tablet press mold with a diameter of 5 - 15 mm. Adjust the pressure to 1.5 - 5 MPa to prepare a super-thick circular AgO cathode with a diameter of 5 - 15 mm, a thickness of 0.5 - 4 mm, and a density of 1.2 - 2.6 g / ml.

[0045] Example 3

[0046] The difference from Example 1 is that in this example, first dissolve 400 - 1200 g of KOH in 2 L of deionized water, heat 10 - 50 g of active zinc powder while it is hot, filter after standing for 24 h to obtain a 4 - 10 mol / L alkali solution. Take 1 L of the KOH alkali solution in a 2 L beaker, and successively add potassium fluoride monohydrate, potassium perfluorobutanesulfonate, zinc trifluoromethanesulfonate, zinc laurate, and zinc oxide. The addition amounts are 0.5 - 1.50 mol, 5 - 30 mmol, 20 - 100 mmol, 10 - 100 mmol, and 0.5 - 2.5 mol respectively. Stir at 150 - 300 rad / min for 30 min, then seal the beaker mouth and place the beaker in an oven at 60 °C and heat for 6 h. After the solution cools, filter it. The filtrate is the prepared electrolyte for the Zn / AgO battery.

[0047] Example 4

[0048] The difference from Example 1 is that in this example, first place the positive electrode sheet into the positive electrode shell of the AG3 battery, successively place the grafted sodium styrenesulfonate composite separator, triacetate cellulose membrane, and olefin fiber grafted with hydroxyl composite separator, add 5 - 25 μL of the electrolyte and then let it stand for two hours. Use the negative electrode shell of the AG3 battery to buckle it onto the zinc paste, use a hydraulic press to flat-press the negative electrode shell, and the zinc paste is directly embedded into the battery shell. The pressure is set to 0.2 MPa. Use a pipette to drop 1 - 10 μL of the electrolyte and let it stand for 2 h. Install the negative electrode shell on the positive electrode shell and complete the button cell packaging using a battery packaging device.

[0049] The above examples only illustrate the principles and effects of the present invention and some applied examples. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A preparation method of a high specific energy Zn / AgO small button secondary battery, characterized in that: It includes the following steps (1) Using an alkaline sodium persulfate solution as an oxidant to oxidize dispersed silver powder as a precursor into an Ag / AgO composite material, and performing surface modification on the Ag / AgO composite material with an alkaline PbS dispersion solution of the same concentration to obtain a three-layer sandwich structure Ag / AgO / AgPbO composite cathode material with a spherical structure, and pressing it into a round AgO cathode by a molding method; In this step, first prepare a highly dispersed aqueous solution with a silver content of 5-30%, then prepare an alkaline sodium persulfate solution with a KOH concentration of 2-8 mol / L and a sodium persulfate concentration of 0.5-5 mol / L. Heat the two solutions to 50-85 °C and then mix them evenly. The reaction time is 60-120 min. Finally, add a PbS alkaline solution with a mass ratio of 3-10%, react for 15-45 min, cool, filter, wash, and dry to obtain the composite cathode material; (2) Prepare a low hydrogen evolution amount KOH alkaline electrolyte with a concentration of 4-10 mol / L using potassium fluoride and fluorinated alkane as corrosion inhibitors; (3) Using elemental zinc powder and zinc oxide as active substances, and using indium oxide, indium hydroxide, lead monoxide, elemental lead powder, sodium stannate or one or more of them as corrosion inhibitors. Heat the PTFE emulsion as a binder in the mixed powder, add ethanol and extrude to form a zinc paste, and vacuum dry to prepare a zinc paste negative electrode; (4) Use an olefin fiber grafted sodium styrene sulfonate composite diaphragm as the battery positive electrode diaphragm, use a triacetate hydrated cellulose composite membrane as the intermediate silver blocking diaphragm, and use an olefin fiber grafted hydroxyl composite diaphragm as the negative electrode diaphragm to complete the battery packaging.

2. A preparation method of a high specific energy Zn / AgO small button secondary battery according to claim 1, characterized in that, The silver powder is spherical particles with a particle size of 1-15 um, accounting for 3-30% of the mass of the precursor solution.

3. A preparation method of a high specific energy Zn / AgO small button secondary battery according to claim 1, characterized in that, The elemental silver powder is dispersed in an aqueous solution containing less than 3% of PVA and PVP dispersants, and the sodium persulfate is 50-200% in excess of the elemental silver powder.

4. A preparation method of a high specific energy Zn / AgO small button secondary battery according to claim 1, characterized in that, In the step (1), the diameter of the AgO cathode is 5-15 mm, the thickness is 0.5-4 mm, and the density is 1.2-2.6 g / ml.

5. A preparation method of a high specific energy Zn / AgO small button secondary battery according to claim 1, characterized in that, The fluorinated alkane in the step (2) includes potassium perfluorobutanesulfonate, zinc trifluoromethanesulfonate and zinc laurate, and the contents of potassium fluoride, potassium perfluorobutanesulfonate, zinc trifluoromethanesulfonate and zinc laurate are 0.5-1.50 mol / L, 5-30 mmol / L, 20-100 mmol / L and 10-100 mmol / L respectively.

6. The preparation method of a high specific energy Zn / AgO small button-shaped secondary battery according to claim 1, characterized in that, in step (3), the vacuum drying temperature of the zinc paste is 60-100 °C, the time is 8-24 h. After drying is completed, turn off the heating and cool to room temperature, then take out the negative electrode; the density of the zinc paste is 0.6-1.5 g / ml, and the thickness of the zinc paste negative electrode is 0.8-1.6 mm.

7. The preparation method of a high specific energy Zn / AgO small button-shaped secondary battery according to claim 1, characterized in that, in step (4), place the positive electrode sheet in the positive electrode shell of the battery, sequentially put in the olefin fiber grafted sodium styrene sulfonate composite separator, the triacetate hydrated cellulose composite membrane and the olefin fiber grafted hydroxyl composite separator, add the electrolyte and then let it stand. Use the negative electrode shell of the battery to be buckled on the zinc paste, embed it in the positive electrode shell of the battery, then drop the electrolyte and let it stand, and use the battery packaging equipment to complete the packaging of the button-shaped battery.

8. The preparation method of a high specific energy Zn / AgO small button-shaped secondary battery according to claim 1, characterized in that, the thickness of the positive electrode separator of the battery is 30-120 μm, and the liquid absorption capacity is greater than 200%; the thickness of the silver-blocking separator in the middle layer is 30-90 μm; the thickness of the negative electrode separator is 30-120 μm, and the liquid absorption capacity is greater than 150%.

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