Thin film magnesium battery magnesium titanate positive electrode target material, preparation method and thin film magnesium battery

Abstract

The present application relates to thin film magnesium battery magnesium titanate positive target material, preparation method and thin film magnesium battery, belong to magnesium battery technical field. Including: magnesium salt powder and titanium dioxide powder are mixed to obtain mixed powder; The mixed powder is put into the ball mill tank and mixed with zirconium oxide ball, then the dispersing agent is added and the mixing and ball milling are continued; Then the binder is added in the ball mill tank, and the ball milling is continued; The synthesized powder after ball milling is passed through a 500 mesh sieve, the sieved synthesized powder is poured into a vibrating mold, pressurized, and a die pressed blank is formed; The blank is put into a cold isostatic pressing machine and pressurized and pressure maintained, to obtain a magnesium titanate positive target material blank after cold isostatic pressing; The magnesium titanate positive target material blank is put into an atmosphere sintering furnace or a vacuum sintering furnace, after multi-stage heat preservation and multi-stage cooling, the furnace is naturally cooled to room temperature, to obtain a thin film magnesium battery magnesium titanate positive target material. The composition of the thin film magnesium battery magnesium titanate positive target material of the present application is uniform, and is convenient for thin film deposition.

Description

Technical Field

[0001] This invention relates to the field of magnesium battery technology, and in particular to a magnesium titanate cathode target for thin-film magnesium batteries, a preparation method thereof, and a thin-film magnesium battery. Background Technology

[0002] Currently, theoretical research on all-solid-state thin-film magnesium batteries has begun. All-solid-state thin-film magnesium batteries utilize solid-state materials for all cell units, including the positive and negative electrodes and the electrolyte. Their structure is simpler than traditional magnesium-ion batteries. The solid electrolyte not only conducts magnesium ions but also acts as a separator, possessing advantages such as high mechanical strength, absence of liquid components, lack of flammable and volatile components, and good temperature resistance. However, research on all-solid-state thin-film magnesium batteries remains theoretical; no technology has yet been developed to provide the actual fabrication techniques and finished products that demonstrate the composition and functional structure of all-solid-state thin-film magnesium batteries. Summary of the Invention

[0003] In view of the above, the present invention aims to provide a magnesium titanate cathode target for thin-film magnesium batteries, a preparation method thereof, and a thin-film magnesium battery.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] On one hand, the present invention provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, comprising:

[0006] Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder. The mass ratio of magnesium salt to titanium dioxide is 1.1-1.5:0.8-1.

[0007] Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls, then add a dispersant and continue mixing and ball milling;

[0008] Step 3: Then add binder into the ball mill jar and continue ball milling;

[0009] Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is poured into a vibrating mold and pressed to form a molded blank.

[0010] Step 5: Place the billet into a cold isostatic press, apply pressure and hold pressure to obtain the cold isostatically pressed magnesium titanate cathode target billet.

[0011] Step 6: Place the magnesium titanate cathode target blank into an atmosphere sintering furnace or a vacuum sintering furnace, and after multi-stage heat preservation and multi-stage cooling, allow it to cool naturally to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0012] Furthermore, step 6, the step of using an atmosphere sintering furnace, includes:

[0013] S601. Place the magnesium titanate cathode target blank into an atmosphere sintering furnace, continuously introduce N2+Ar mixed gas, raise the temperature from room temperature to 170-190℃, and hold for 2.5-4 hours.

[0014] S602, heat up again to 590-610℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 4-6 hours;

[0015] S603, heat up again to 740-760℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 7-9 hours;

[0016] S604, heat up again to 940-960℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 9-11 hours;

[0017] S605, heat up again to 1030~1060℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 7~9h;

[0018] S606, slowly cool to 490-510℃ in the furnace, and hold for 3-5 hours;

[0019] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0020] Furthermore, step 6, which involves using a vacuum sintering furnace, includes:

[0021] S601. Place the magnesium titanate cathode target blank into a vacuum sintering furnace, maintaining a vacuum level of 10. -3 Below Pa, the temperature is raised from room temperature to 170–190℃ and held for 2.5–4 hours;

[0022] S602, raise the temperature again to 590-610℃, and keep it at that temperature for 4-6 hours;

[0023] S603, heat again to 740-760℃, and keep warm for 7-9 hours;

[0024] S604, heat again to 940-960℃, and hold for 9-11 hours;

[0025] S605, heat again to 1030~1060℃, and keep warm for 7~9 hours;

[0026] S606, slowly cool to 490-510℃ in the furnace, and hold for 3-5 hours;

[0027] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0028] Furthermore, in step 1, the magnesium salt includes one or more of magnesium oxide, magnesium carbonate, magnesium nitrate, and magnesium hydroxide.

[0029] Furthermore, in step 2, the mass ratio of dispersant to mixed powder is controlled to be 1.4 to 1.8:100.

[0030] Furthermore, in step 2, the ball milling process includes:

[0031] S201. Ball milling in a milling jar at an initial speed of 100-140 rpm for 3-5 hours;

[0032] S202. Grind the balls in the mill at a speed of 320-340 rpm for more than 12 hours.

[0033] Furthermore, in step 3, the mass ratio of the binder to the mixed powder is controlled to be 0.4 to 0.6:100.

[0034] Furthermore, in step 4, the pressure is controlled at 1450-1550 tons to form a molded blank.

[0035] Furthermore, in step 5, the pressure is controlled to be increased to 300-350 MPa and held for 50-70 minutes.

[0036] The present invention also provides a magnesium titanate cathode target for thin-film magnesium batteries, which is prepared by the above-described preparation method.

[0037] The present invention also provides an all-solid-state thin-film magnesium battery, wherein the positive electrode of the all-solid-state thin-film magnesium battery is prepared using the above-mentioned magnesium titanate positive electrode target for thin-film magnesium batteries.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1) The preparation method of this invention first mixes magnesium salt powder and titanium dioxide powder to obtain a mixed powder, then mixes the above mixed powder with zirconia balls, then adds a dispersant and continues mixing and ball milling; then adds a binder and continues ball milling; the ball-milled synthetic powder is sieved (e.g., 500 mesh), poured into a vibrating mold, and pressed to form a molded blank; the blank is placed in a cold isostatic press and pressed and held to obtain a cold isostatically pressed magnesium titanate cathode target blank; finally, the magnesium titanate cathode target blank is placed in an atmosphere sintering furnace or a vacuum sintering furnace, and after multi-stage heat preservation and multi-stage cooling, it is naturally cooled to room temperature with the furnace to obtain a thin-film magnesium battery magnesium titanate cathode target. The preparation method of this invention ensures the preparation of a thin-film magnesium battery magnesium titanate cathode target by precisely controlling the proportion of raw materials, the order of addition of each raw material, the ball milling process parameters, the sintering steps, and the process parameters of each step.

[0040] 2) The magnesium titanate cathode target for thin-film magnesium batteries of the present invention has a uniform composition, no segregation, good grain size consistency, controllable grain deviation, no single phase or defect components, and no cracks in the target material, which facilitates thin film deposition.

[0041] 3) The positive electrode layer of the all-solid-state thin-film magnesium battery of the present invention is prepared using the magnesium titanate positive electrode target of the thin-film magnesium battery of the present invention. The all-solid-state thin-film magnesium battery of the present invention has high safety and extremely high capacity and capacity retention. In addition, the all-solid-state thin-film magnesium battery of the present invention also has excellent interfacial bonding and coordination, with very low interfacial internal resistance. It can easily realize the direct series connection of multiple single cells, the direct parallel connection of multiple single cells, and the series and parallel combination of multiple single cells, which conveniently achieves the goal of increasing the output voltage of the battery, increasing the single cell capacity of the battery pack, or achieving a perfect combination of voltage boosting and capacity expansion.

[0042] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description. Attached Figure Description

[0043] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] Figure 1 This is a schematic diagram of the positive electrode target of Embodiment 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of the positive electrode target material according to Embodiment 2 of the present invention;

[0046] Figure 3 This is a schematic diagram of the positive electrode target of Embodiment 3 of the present invention;

[0047] Figure 4 This is a schematic diagram of the positive electrode target of Comparative Example 2 of the present invention. Detailed Implementation

[0048] The preferred embodiments of the present invention are described in detail below, which are mainly used to explain the principles of the present invention and are not intended to limit the scope of the present invention.

[0049] This invention provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, comprising:

[0050] Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder;

[0051] Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls, then add a dispersant and continue mixing and ball milling;

[0052] Step 3: Then add binder into the ball mill jar and continue ball milling;

[0053] Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is weighed and then poured into a vibrating mold. Pressure is applied to form a molded blank.

[0054] Step 5: Place the billet into a cold isostatic press, apply pressure and hold pressure to obtain the cold isostatically pressed magnesium titanate cathode target billet.

[0055] Step 6: Place the magnesium titanate cathode target blank into an atmosphere sintering furnace or a vacuum sintering furnace, and after multi-stage heat preservation and multi-stage cooling, allow it to cool naturally to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0056] Specifically, in step 1 above, the magnesium salt may include one or more of magnesium oxide, magnesium carbonate, magnesium nitrate, and magnesium hydroxide.

[0057] Specifically, in step 1 above, the mass ratio of magnesium salt to titanium dioxide is controlled at 1.1-1.5:0.8-1.

[0058] Specifically, in step 2 above, to ensure uniform mixing of the powders and to control the particle size of the powders by adjusting the size of the zirconia balls, thus ensuring uniformity in grain size and crystal structure of the sintered magnesium titanate product, and to guarantee that the powders are broken up and in close contact, reducing the chemical kinetic barrier during synthesis, the particle size of the zirconia balls is controlled to be 0.45 mm to 1.35 mm. When the particle size of the zirconia balls is outside this range, the particle size deviation of the mixed powder is large, the mixing is uneven, many elemental substances are present, and the sintered target material cannot be sputtered.

[0059] Specifically, in step 2 above, the grinding jar is a hard ceramic jar or a stainless steel jar lined with hard ceramic.

[0060] Specifically, in step 2 above, the total volume of the zirconia balls is controlled to be no more than 1 / 4 of the volume of the ball mill jar, and the total volume of the mixed powder is 1 / 5 to 2 / 5 of the volume of the ball mill jar. Preferably, the total volume of the mixed powder is 1 / 3 of the volume of the ball mill jar.

[0061] Specifically, in step 2 above, considering that too much dispersant would be wasteful, while too little dispersant would cause the powder to agglomerate and fail to mix and contact sufficiently, which would be detrimental to synthesis and sintering, the mass ratio of dispersant to mixed powder is controlled at 1.4–1.8:100.

[0062] Specifically, in step 2 above, the dispersant may include isopropanol and isotetracycline. Preferably, the mass ratio of isopropanol to isotetracycline is 1-3:4-6.

[0063] Specifically, in step 2 above, the ball milling process includes:

[0064] S201. Ball milling in the mill jar at an initial speed of 100-140 rpm for 3-5 hours;

[0065] S202. Grind the balls in a milling jar at a speed of 320-340 rpm for more than 12 hours.

[0066] Specifically, in step 2 above, the ball milling process first uses a lower rotation speed and then a higher rotation speed. This ensures that the powder is mixed evenly, facilitating subsequent synthesis reactions. Without using the appropriate ball milling parameters, the mixture will be uneven, containing many elemental substances, and the sintered target material will not be able to be sputtered.

[0067] Specifically, in step 3 above, polyvinyl butyral can be used as the binder. Too much binder will be wasteful, while too little binder will prevent the uniformly mixed raw material powder from fully contacting and rapidly participating in the chemical reaction during sintering. Therefore, the mass ratio of binder to mixed powder should be controlled at 0.4–0.6:100.

[0068] Specifically, in step 3 above, in order to ensure that the powder is mixed evenly, the ball mill speed is controlled at 160-180 rpm and the ball milling time is 6-8 hours.

[0069] Specifically, in step 4 above, to ensure the uniformity of grain size and crystal phase structure of the sintered magnesium titanate product, the synthetic powder is controlled to pass through a 500-mesh sieve. If this parameter is not within the range, the powder particle size will be dispersed, resulting in large voids in the target compact, preventing complete ceramization after sintering and hindering sputtering deposition.

[0070] Specifically, in step 4 above, considering that excessive pressure would place high demands on the equipment, while insufficient pressure would be ineffective, the pressure is controlled at 1450–1550 tons to form the molded blank.

[0071] Specifically, in step 5 above, considering that excessive pressure during the cold isostatic pressing process places high demands on the equipment, while insufficient pressure renders it ineffective, the pressure is controlled to be increased to 300–350 MPa and held for 50–70 minutes.

[0072] Specifically, step 6 above, which involves using an atmosphere sintering furnace, includes:

[0073] S601. Place the magnesium titanate cathode target blank into an atmosphere sintering furnace, continuously introduce N2+Ar mixed gas, raise the temperature from room temperature to 170-190℃, and hold for 2.5-4 hours; wherein, the volume ratio of N2 to Ar is 5.5-6:4.

[0074] S602, heat again to 590-610℃, and continuously purge N2+Ar mixed gas for 4-6 hours; wherein the volume ratio of N2 to Ar is 5.5-6:4.

[0075] S603, heat again to 740-760℃, and continuously purge N2+Ar mixed gas for 7-9 hours; wherein, the volume ratio of N2 to Ar is 5.5-6:4.

[0076] S604, heat again to 940-960℃, and continuously purge N2+Ar mixed gas for 9-11 hours; wherein the volume ratio of N2 to Ar is 5.5-6:4.

[0077] S605, heat again to 1030-1060℃, and continuously purge N2+Ar mixed gas for 7-9 hours; wherein, the volume ratio of N2 to Ar is 5.5-6:4.

[0078] S606, slowly cool to 490-510℃ in the furnace, and hold for 3-5 hours;

[0079] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0080] Specifically, in S606 and S607 above, in order to ensure the uniformity of the microstructure of the obtained magnesium titanate cathode target, it is necessary to first slowly cool it to 490-510℃ in the furnace and hold it for 3-5 hours; then cool it naturally to room temperature in the furnace.

[0081] Specifically, step 6 above, which involves using a vacuum sintering furnace, includes:

[0082] S601. Place the magnesium titanate cathode target blank into a vacuum sintering furnace, maintaining a vacuum level of 10. -3 Below Pa, the temperature is raised from room temperature to 170–190℃ and held for 2.5–4 hours;

[0083] S602, raise the temperature again to 590-610℃, and keep it at that temperature for 4-6 hours;

[0084] S603, heat again to 740-760℃, and keep warm for 7-9 hours;

[0085] S604, heat again to 940-960℃, and hold for 9-11 hours;

[0086] S605, heat again to 1030~1060℃, and keep warm for 7~9 hours;

[0087] S606, slowly cool to 490-510℃ in the furnace, and hold for 3-5 hours;

[0088] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0089] Specifically, in S602 to S605 above, the vacuum level is always maintained at 10.-3 Below pa.

[0090] Specifically, in S606 and S607 above, in order to ensure the uniformity of the microstructure of the obtained magnesium titanate cathode target, it is necessary to first slowly cool it to 490-510℃ in the furnace and hold it for 3-5 hours; then cool it naturally to room temperature in the furnace.

[0091] Specifically, in step 6 above, the parameters such as temperature, atmosphere, and holding time for each of the multiple heating stages are all taken into account the chemical reaction kinetics requirements of sintering. These parameters are controlled to ensure the uniformity of composition and the required grain structure of the synthesized magnesium titanate during the sintering process. Sintering outside this temperature range will result in incomplete ceramization of the target material, leading to over-sintering, under-sintering, porosity, and deformation, rendering the target material unusable.

[0092] Specifically, in step 6 above, the resulting magnesium titanate cathode target for thin-film magnesium batteries has a uniform composition, no segregation, good grain size consistency, controllable grain deviation, no single-phase or defect components, and no cracks within the target, facilitating thin-film deposition. The grain size of the magnesium titanate cathode target for thin-film magnesium batteries is between 340nm and 400nm, the flatness of the target after sintering is approximately 0.12 to 0.18mm, and the relative density of the sintered target is approximately 94% to 96.5%.

[0093] The present invention also provides a magnesium titanate cathode target for thin-film magnesium batteries, which is prepared by the above method.

[0094] The present invention also provides an all-solid-state thin-film magnesium battery, wherein the positive electrode of the all-solid-state thin-film magnesium battery is prepared using the above-mentioned magnesium titanate positive electrode target for thin-film magnesium batteries.

[0095] Specifically, the aforementioned all-solid-state thin-film magnesium battery includes a positive electrode layer, an electrolyte layer, and a negative electrode layer, with the positive electrode layer prepared using the aforementioned magnesium titanate positive electrode target for thin-film magnesium batteries.

[0096] Specifically, the preparation method of the above-mentioned all-solid-state thin-film magnesium battery includes:

[0097] Step 1: Deposit a thin film of magnesium anode on the surface of copper foil;

[0098] Step 2: Next, a solid electrolyte film is deposited on the negative electrode magnesium film;

[0099] Step 3: Deposit a positive electrode film on the solid electrolyte film using the magnesium titanate positive electrode target of the thin-film magnesium battery described above;

[0100] Step 4: After formation, an all-solid-state thin-film magnesium battery is obtained.

[0101] Specifically, the all-solid-state thin-film magnesium battery of the present invention, in addition to high safety, also has high capacity and capacity retention. For example, with a capacity of 13780 mAh or higher (e.g., 13780–40450 mAh), the capacity remains essentially unchanged after more than 10,000 cycles. Furthermore, the all-solid-state thin-film magnesium battery of the present invention also has excellent interfacial bonding and compatibility, with very low interfacial internal resistance, for example, less than 0.01 ohms / cm. 2 It can very easily realize the direct series connection of multiple single cells, the direct parallel connection of multiple single cells, and the series and parallel combination of multiple single cells, which can conveniently increase the output voltage of the battery, increase the single cell capacity of the battery pack, or achieve a perfect combination of voltage boosting and capacity expansion.

[0102] The preparation method and application of the magnesium titanate cathode target for thin-film magnesium batteries of the present invention will be further described below with reference to specific embodiments. Unless otherwise specified, all raw materials used are commercially available.

[0103] Example 1

[0104] This embodiment provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, including:

[0105] Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder; the magnesium salt used is magnesium oxide, and the mass ratio of magnesium oxide to titanium dioxide is 1.1:0.8;

[0106] Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls with a particle size of 0.5 mm to 1.3 mm. Then add a dispersant and continue mixing and ball milling. The ball mill jar is a hard ceramic jar. The total volume of the zirconia balls occupies 1 / 4 of the volume of the ball mill jar, and the total volume of the mixed powder occupies 1 / 3 of the volume of the ball mill jar. The mass ratio of dispersant to mixed powder is 1.7:100.

[0107] Specifically, in step 2, the ball milling process includes:

[0108] S201. The ball mill jar is used to ball mill at an initial speed of 120 rpm for 4 hours.

[0109] S202, ball milling in a milling jar at a speed of 330 rpm for 13 hours;

[0110] Step 3: Then add binder into the ball mill jar and ball mill at 165 rpm for 7 hours; the mass ratio of binder to mixed powder is 0.5:100.

[0111] Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is weighed and then poured into a vibrating mold. It is then pressed with 1500 tons to form a molded blank.

[0112] Step 5: Place the billet into a cold isostatic press, pressurize it to 320 MPa, hold the pressure for 60 minutes, and obtain the cold isostatically pressed magnesium titanate cathode target billet.

[0113] Step 6: Place the magnesium titanate cathode target blank into an atmosphere sintering furnace for multi-stage heat preservation and multi-stage cooling, and then allow it to cool naturally to room temperature with the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0114] Step 6 includes:

[0115] S601. Place the magnesium titanate cathode target blank into an atmosphere sintering furnace and continuously introduce a N2+Ar (ratio 6:4) mixed gas. Raise the temperature from room temperature to 180℃ and hold for 3 hours.

[0116] S602, raise the temperature to 600℃ again, and keep it at that temperature for 5 hours while continuously introducing a N2+Ar (ratio 6:4) mixed gas;

[0117] S603, raise the temperature again to 750℃, and continuously introduce a N2+Ar (ratio 6:4) mixed gas, and keep it at this temperature for 8 hours;

[0118] S604, raise the temperature again to 950℃, and continuously introduce a N2+Ar (ratio 6:4) mixed gas, and keep it at this temperature for 10 hours;

[0119] S605, raise the temperature again to 1050℃, and continuously introduce a N2+Ar (ratio 6:4) mixed gas, and keep it at this temperature for 8 hours;

[0120] S606, slowly cool to 500℃ in the furnace and hold for 4 hours;

[0121] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0122] The magnesium titanate cathode target for thin-film magnesium batteries obtained in this embodiment is as follows: Figure 1 As shown, the positive electrode target has a uniform composition, no segregation, good grain size consistency, controllable grain deviation, no single phase or defect components, and no cracks within the target, facilitating thin film deposition. Specifically, in this embodiment, the grain size of the magnesium titanate positive electrode target for the thin-film magnesium battery is between 340nm and 380nm, the flatness of the target after sintering is about 0.14mm, and the relative density of the sintered target is about 94.5%.

[0123] Example 2

[0124] This embodiment provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, including:

[0125] Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder; the magnesium salt used is magnesium oxide, and the mass ratio of magnesium oxide to titanium dioxide is 1.2:0.8;

[0126] Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls with a particle size of 0.5 mm to 1.3 mm. Then add a dispersant and continue mixing and ball milling. The ball mill jar is a hard ceramic jar. The total volume of the zirconia balls occupies 1 / 3 of the volume of the ball mill jar, and the total volume of the mixed powder occupies 1 / 3 of the volume of the ball mill jar. The mass ratio of dispersant to mixed powder is 1.5:100.

[0127] Specifically, in step 2, the ball milling process includes:

[0128] S201. The ball mill jar is used to ball mill at an initial speed of 140 rpm for 3 hours.

[0129] S202, ball milling in a milling jar at a speed of 330 rpm for 13 hours;

[0130] Step 3: Then add binder into the ball mill jar and ball mill at 160 rpm for 8 hours; the mass ratio of binder to mixed powder is 0.6:100.

[0131] Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is weighed and then poured into a vibrating mold. It is then pressed with 1550 tons to form a molded blank.

[0132] Step 5: Place the billet into a cold isostatic press, pressurize it to 310 MPa, hold the pressure for 65 minutes, and obtain the cold isostatically pressed magnesium titanate cathode target billet.

[0133] Step 6: Place the magnesium titanate cathode target blank into an atmosphere sintering furnace for multi-stage heat preservation and multi-stage cooling, and then allow it to cool naturally to room temperature with the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0134] Step 6 includes:

[0135] S601. Place the magnesium titanate cathode target blank into an atmosphere sintering furnace and continuously introduce a N2+Ar (ratio 5.5:4) mixed gas. Raise the temperature from room temperature to 190℃ and hold for 3 hours.

[0136] S602, raise the temperature again to 610℃, and keep it at that temperature for 4 hours while continuously purging the N2+Ar (6:4 ratio) mixed gas;

[0137] S603, heat up to 745℃ again, and continuously purify with a N2+Ar (6:4 ratio) gas mixture for 9 hours;

[0138] S604, raise the temperature again to 940℃, and continuously introduce a N2+Ar (ratio 6:4) mixed gas, and keep it at this temperature for 11 hours;

[0139] S605, raise the temperature again to 1050℃, and continuously introduce a N2+Ar (ratio 6:4) mixed gas, and keep it at this temperature for 8 hours;

[0140] S606, slowly cooled to 495℃ in the furnace, and held at that temperature for 4.5 hours;

[0141] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0142] The magnesium titanate cathode target for thin-film magnesium batteries obtained in this embodiment is as follows: Figure 2 As shown, the positive electrode target has a uniform composition, no segregation, good grain size consistency, controllable grain deviation, no single phase or defect components, and no cracks within the target, facilitating thin film deposition. Specifically, in this embodiment, the grain size of the magnesium titanate positive electrode target for the thin-film magnesium battery is between 345nm and 390nm, the flatness of the target after sintering is about 0.15mm, and the relative density of the sintered target is about 95%.

[0143] Example 3

[0144] This embodiment provides a method for preparing a magnesium titanate cathode target for a thin-film magnesium battery. Steps 1-5 are the same as in Example 1 and will not be repeated here. The method also includes:

[0145] Step 6: Place the magnesium titanate cathode target blank into a vacuum sintering furnace, perform multi-stage heat preservation and multi-stage cooling, and then allow it to cool naturally to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0146] Step 6 includes:

[0147] S601. Place the magnesium titanate cathode target blank into a vacuum sintering furnace, maintaining a vacuum level of 10. -3 Below Pa, the temperature is raised from room temperature to 180℃ and held for 3 hours;

[0148] S602, reheat to 600℃ and keep warm for 5 hours;

[0149] S603, heat up to 750℃ again and keep warm for 8 hours;

[0150] S604, heat up to 950℃ again and keep warm for 10 hours;

[0151] S605, heat up to 1050℃ again, and keep warm for 8 hours;

[0152] S606, slowly cool to 500℃ in the furnace and hold for 4 hours;

[0153] S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0154] Specifically, in S602 to S605 above, the vacuum level is always maintained at 10. -3 Below pa.

[0155] The magnesium titanate cathode target for thin-film magnesium batteries obtained in this embodiment is as follows: Figure 3 As shown, the cathode target has a uniform composition, no segregation, good grain size consistency, controllable grain deviation, no single phase or defect components, and no cracks within the target, facilitating thin film deposition. Specifically, in this embodiment, the grain size of the magnesium titanate cathode target for the thin-film magnesium battery is between 350nm and 400nm, the flatness of the target after sintering is about 0.145mm, and the relative density of the sintered target is about 95.5%.

[0156] Example 4

[0157] This embodiment provides an all-solid-state thin-film magnesium battery. The fabrication method of this embodiment for depositing a single-cell all-solid-state thin-film magnesium battery includes:

[0158] Step 1: Deposit a negative electrode magnesium film on a 1 square meter copper foil surface. The thickness of the negative electrode magnesium film is 4.5 μm.

[0159] Step 2: Next, a solid electrolyte film is deposited on the negative electrode magnesium film, with a thickness of 1.5 μm;

[0160] Step 3: Deposit a positive electrode film on the solid electrolyte film using the magnesium titanate positive electrode target of the thin-film magnesium battery described in Example 1 above; the thickness of the positive electrode film is 15 μm;

[0161] Step 4: After formation, an all-solid-state thin-film magnesium battery is obtained.

[0162] The interfacial resistance of the all-solid-state thin-film magnesium battery in this embodiment is less than 0.01 ohms / cm. 2 The capacity is 13780.8 (mAh), and the capacity remains basically unchanged after more than 10,000 cycles.

[0163] Example 5

[0164] This embodiment provides an all-solid-state thin-film magnesium battery. The fabrication method for this embodiment involves depositing two series-connected all-solid-state thin-film magnesium batteries.

[0165] The magnesium anode film thickness of each thin-film magnesium battery was 5.5 μm, deposited on a 1 square meter copper foil surface. The solid electrolyte film thickness of each subsequent battery was 2.0 μm. Using the magnesium titanate cathode target from Example 2, the cathode film thickness of the resulting thin-film magnesium battery was 18.5 μm. After formation, the battery achieved a capacity of 16996.3 mA h; the capacity remained essentially unchanged after more than 10,000 cycles; and the interfacial resistance was less than 0.01 ohms / cm. 2 .

[0166] Example 6

[0167] This embodiment provides an all-solid-state thin-film magnesium battery. The method for depositing two parallel all-solid-state thin-film magnesium batteries includes:

[0168] The thickness of the negative electrode magnesium film deposited on the surface of a 1 square meter copper foil for each battery is 6.5 μm. The thickness of the solid electrolyte film deposited on each battery is then 2.5 μm. Finally, using the magnesium titanate cathode target from Example 3, the thickness of the positive electrode film deposited is 22 μm. The resulting battery, after formation, has a capacity of 40423.6 mA h; the capacity remains essentially unchanged after more than 10,000 cycles; and the interfacial resistance is less than 0.01 ohms / cm. 2 .

[0169] Comparative Example 1

[0170] This comparative example provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, as detailed below:

[0171] Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder; the magnesium salt used is magnesium oxide, and the mass ratio of magnesium oxide to titanium dioxide is 1.1:0.8;

[0172] Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls with a particle size of 0.5 mm to 1.3 mm. Then add a dispersant and continue mixing. Ball mill at 150 rpm for 3 hours. The ball mill jar is a hard ceramic jar. The total volume of the zirconia balls occupies 2 / 5 of the volume of the ball mill jar, and the total volume of the mixed powder occupies 1 / 3 of the volume of the ball mill jar. The mass ratio of dispersant to mixed powder is 1.3:100.

[0173] Step 3: Then add binder into the ball mill jar and ball mill at 145 rpm for 5 hours; the mass ratio of binder to mixed powder is 0.5:100.

[0174] Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is weighed and then poured into a vibrating mold. It is then pressed with 900 tons to form a molded blank.

[0175] Step 5: Place the billet into a cold isostatic press, pressurize it to 200 MPa, and hold the pressure for 40 minutes. However, a suitable magnesium titanate cathode target billet cannot be obtained.

[0176] The process parameters in this comparative example are unsuitable, and it is impossible to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

[0177] Comparative Example 2

[0178] This comparative example provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, as detailed below:

[0179] In step 2 of this comparative example, the particle size of the zirconia spheres is 1.8–2.5 mm; S601 is omitted, and the remaining steps are the same as those in Example 1.

[0180] The positive electrode target of this comparative example is as follows: Figure 4 As shown, the target material has large grain deviations, uneven mixing, and contains many elemental substances, making it impossible to sputter the sintered target material.

[0181] Comparative Example 3

[0182] This comparative example provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, as detailed below:

[0183] In step 2 of this comparative example, the ball milling process is directly carried out at 300-350 rpm for more than 12 hours; S602 is omitted, and the remaining steps are the same as those in Example 1.

[0184] In this comparative example, the powder was not mixed evenly and contained many elemental substances, so the sintered target material could not be sputtered.

[0185] Comparative Example 4

[0186] This comparative example provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, as detailed below:

[0187] In step 4 of this comparative example, the synthetic powder is controlled to pass through a 300-mesh sieve; the remaining steps are the same as those in Example 1.

[0188] The target blank in this comparative example has large voids, and cannot be completely ceramicized after sintering, thus making sputtering deposition impossible.

[0189] Comparative Example 5

[0190] This comparative example provides a method for preparing a magnesium titanate cathode target for thin-film magnesium batteries, as detailed below:

[0191] In step 6 of this comparative example, steps S603-S607 are performed directly; the remaining steps are the same as those in Example 1.

[0192] The target material in this comparative example cannot be fully ceramicized and is therefore unusable.

[0193] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a magnesium titanate cathode target for a thin-film magnesium battery, characterized in that, include: Step 1: Mix magnesium salt powder and titanium dioxide powder to obtain a mixed powder, wherein the mass ratio of magnesium salt to titanium dioxide is 1.1~1.5:0.8~1; Step 2: Place the above mixed powder into a ball mill jar and mix it with zirconia balls, then add a dispersant and continue mixing and ball milling; Step 3: Then add binder into the ball mill jar and continue ball milling; Step 4: After ball milling, the synthetic powder is passed through a 500-mesh sieve. The sieved synthetic powder is poured into a vibrating mold and pressed to form a molded blank. Step 5: Place the billet into a cold isostatic press, apply pressure and hold pressure to obtain the cold isostatically pressed magnesium titanate cathode target billet. Step 6: Place the magnesium titanate cathode target blank into an atmosphere sintering furnace or a vacuum sintering furnace, and after multi-stage heat preservation and multi-stage cooling, allow it to cool naturally to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries. In step 2, the particle size of the zirconia balls is controlled to be 0.45 mm to 1.35 mm; the total volume of the zirconia balls is controlled to occupy no more than 1 / 4 of the volume of the ball mill jar, and the total volume of the mixed powder occupies 1 / 5 to 2 / 5 of the volume of the ball mill jar. In step 2, the ball milling process includes: S201, ball milling in a milling jar at an initial speed of 100-140 rpm for 3-5 hours; S202, ball milling in a milling jar at a speed of 320~340 rpm for more than 12 hours; In step 4, the pressure is controlled at 1450~1550 tons to form a molded blank; In step 5, the pressure is controlled to be increased to 300~350MPa and held for 50~70min. Step 6, the step of using an atmosphere sintering furnace, includes: S601. Place the magnesium titanate cathode target blank into an atmosphere sintering furnace, continuously introduce N2+Ar mixed gas, raise the temperature from room temperature to 170~190℃, and hold for 2.5~4 hours. S602, heat up again to 590~610℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 4~6 hours; S603, heat up again to 740~760℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 7~9 hours; S604, heat up again to 940~960℃, and continuously purge N2+Ar mixed gas, and keep at this temperature for 9~11 h; S605, heat up again to 1030~1060℃, and continuously purge with N2+Ar mixed gas, and keep at this temperature for 7~9 hours; S606, slowly cool to 490~510℃ in the furnace, and hold for 3~5 hours; S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries; Step 6, the step of using a vacuum sintering furnace, includes: S601. Place the magnesium titanate cathode target blank into a vacuum sintering furnace, maintaining a vacuum level of 10. -3 Below Pa, the temperature is raised from room temperature to 170~190℃ and held for 2.5~4 hours; S602, raise the temperature again to 590~610℃, and keep it warm for 4~6 hours; S603, heat again to 740~760℃, and keep warm for 7~9 hours; S604, heat again to 940~960℃, and keep warm for 9~11 hours; S605, heat up again to 1030~1060℃, and keep warm for 7~9 hours; S606, slowly cool to 490~510℃ in the furnace, and hold for 3~5 hours; S607, and then naturally cooled to room temperature in the furnace to obtain the magnesium titanate cathode target for thin-film magnesium batteries.

2. The preparation method according to claim 1, characterized in that, In step 6, the step of using an atmosphere sintering furnace, S601, the magnesium titanate cathode target blank is placed in the atmosphere sintering furnace, and N2+Ar mixed gas is continuously introduced, the temperature is raised from room temperature to 180~190℃, and held for 2.5~4h.

3. The preparation method according to claim 1, characterized in that, In step 6, the step of using a vacuum sintering furnace involves, in step S601, placing the magnesium titanate cathode target blank into the vacuum sintering furnace and maintaining a vacuum degree of 10. -3 Below Pa, the temperature is raised from room temperature to 180~190℃ and held for 2.5~4 hours.

4. The preparation method according to claim 1, characterized in that, In step 2, the mass ratio of dispersant to mixed powder is controlled to be 1.4~1.8:

100.

5. The preparation method according to claim 1, characterized in that, In step 2, S201 and the ball milling jar are ball-milled at an initial speed of 120-140 rpm for 3-5 hours.

6. The preparation method according to claim 1, characterized in that, In step 3, the mass ratio of binder to mixed powder is controlled to be 0.4~0.6:

100.

7. The preparation method according to claim 1, characterized in that, In step 4, the pressure is controlled at 1500~1550 tons to form a molded blank.

8. The preparation method according to claim 1, characterized in that, In step 5, the pressure is controlled to be increased to 300~320MPa and held for 50~70min.

9. A magnesium titanate cathode target for thin-film magnesium batteries, characterized in that, The magnesium titanate cathode target for the thin-film magnesium battery is prepared by the preparation method described in any one of claims 1-8.

10. A fully solid-state thin-film magnesium battery, characterized in that, The positive electrode of the all-solid-state thin-film magnesium battery is prepared using the magnesium titanate positive electrode target of the thin-film magnesium battery as described in claim 9.

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