Silver vanadium oxide positive electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrode materials, and provides a silver-vanadium oxide positive electrode material and a preparation method and application thereof, the chemical formula of the silver-vanadium oxide positive electrode material is Ag2V4O11, and the specific surface area is 0.6-1.5 m < 2 > / g; under the instantaneous current of 20mA / cm < 2 >, the average lag voltage is less than 350mV; under the instantaneous current of 40mA / cm < 2 >, the average lag voltage is less than 580mV; the BET is controlled within the range of 0.6-1.5 m < 2 > / g, so that the silver vanadium oxide positive electrode material capable of sufficiently reducing or avoiding the influence of internal resistance increase and voltage delay can be obtained. According to the design of the preparation method, low-temperature pre-calcination is carried out based on a decomposition window determined by DSC to form a segmented heat treatment process, the crystallinity and integrity of the silver-vanadium oxide crystal are remarkably improved, and the specific surface area (BET) of the material can be synchronously reduced, so that the specific surface area of the material reaches 0.6-1.5 m < 2 > / g.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrode materials, and relates to a silver vanadium oxide positive electrode material and a preparation method and use thereof. BACKGROUND

[0002] An implantable cardioverter defibrillator (ICD) is a medical device used to prevent sudden cardiac death. Its core function is to monitor heart rhythm and automatically release an electric shock to restore normal rhythm when detecting life-threatening arrhythmias such as ventricular tachycardia or ventricular fibrillation.

[0003] The efficient operation of an ICD not only depends on the high energy density, long life, excellent safety and reliability of its battery and electrode material, but also requires other special and stringent requirements. An ICD essentially includes an electrochemical battery, a microprocessor, and at least one electrolytic capacitor. The microprocessor mainly performs heart sensing and pacing functions, requiring the battery to continuously provide a current of 1 microampere to 100 milliamperes, which requires the electrode material to maintain stable power supply at different voltage stages. The electrolytic capacitor is used to provide an electric shock to the heart after charging for defibrillation, which requires the battery to provide a high-rate pulse discharge load to maintain a charging current of about 1 ampere to 4 amperes. At the same time, the charging process also needs to consider the shortening of the charging time, so the electrode material not only needs to have the rate capability of large current output, but also needs to minimize or avoid the effects of internal resistance growth and voltage delay.

[0004] Among the many electrode materials and systems, traditional lithium battery systems such as lithium / thionyl chloride (Li / SOCl2) have high energy density, but cannot meet the high-power pulse and safety requirements of ICDs. While lithium / manganese dioxide (Li / MnO2) batteries have good power characteristics, they have the risk of voltage drop after long-term use. Silver vanadium oxide-based lithium primary batteries have multiple platform discharge characteristics and can provide stable high-power output at very low self-discharge rates, making them suitable for ICD devices. However, silver vanadium oxide-based electrode materials still have the above-mentioned problems related to internal resistance growth and voltage delay, and there is still potential for further optimization and improvement. SUMMARY

[0005] In view of the problems in the prior art, the present application aims to provide a silver vanadium oxide positive electrode material and a preparation method and use thereof. The silver vanadium oxide positive electrode material has the chemical formula Ag2V4O 11 , a specific surface area of 0.6-1.5 m 2 / g, an average hysteresis voltage of <330 mV at 20 mA / cm 2 , and an average hysteresis voltage of <330 mV at 40 mA / cm 2Under instantaneous current, the average hysteresis voltage is <550mV; the BET is controlled between 0.6 and 1.5mV. 2 The / g range was used to obtain silver vanadium oxide cathode materials that could fully reduce or avoid the effects of internal resistance growth and voltage delay.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a silver vanadium oxide cathode material, wherein the silver vanadium oxide cathode material comprises Ag₂V₄O₂ 11 Its specific surface area is 0.6–1.5 m². 2 / g; at 20mA / cm 2 Under instantaneous current, the average hysteresis voltage is <330mV; at 40mA / cm 2 Under instantaneous current, the average hysteresis voltage is <550mV.

[0008] The specific surface area (BET value) of the silver vanadium oxide cathode material described in this invention is >1.5 m². 2 At a concentration of / g, the active surface area is too large, which exacerbates the dissolution of vanadium into the electrolyte. The dissolved high-valence vanadium ions migrate to the negative electrode, catalyzing an abnormal thickening of the solid electrolyte interphase (SEI) film on the lithium metal surface, thus reducing the Li-E ratio. + The diffusion rate is affected, and the concentration polarization during pulse discharge is intensified, increasing the hysteresis voltage difference and affecting the pulse discharge. From the perspective of ICD application, the increase in hysteresis voltage means a longer charging time for the defibrillator capacitor and a decrease in usable capacity. To break this vicious cycle, this invention proposes BET windowing control, keeping the BET within a relatively small range of 0.6–1.5 m. 2 The / g range was used to obtain silver vanadium oxide cathode materials that could fully reduce or avoid the effects of internal resistance growth and voltage delay.

[0009] The specific surface area of ​​the silver vanadium oxide cathode material described in this invention is 0.6–1.5 m². 2 / g, for example 0.6m 2 / g, 0.7m 2 / g, 0.8m 2 / g, 0.9m 2 / g、1m 2 / g, 1.1m 2 / g, 1.2m 2 / g, 1.3m 2 / g, 1.4m 2 / g or 1.5m 2 / g etc.

[0010] The silver vanadium oxide cathode material described in this invention operates at 20 mA / cm². 2at 40 mA / cm2, an average overpotential < 350 mV, for example 349 mV, 345 mV, 342 mV, 340 mV, 338 mV, 335 mV, 331 mV, 329 mV, 325 mV, 322 mV, 320 mV, 318 mV, 315 mV, 313 mV, 310 mV, 307 mV, 305 mV, 302 mV, or 300 mV, etc. 2 at 40 mA / cm2, an average overpotential < 580 mV, for example 579 mV, 575 mV, 572 mV, 570 mV, 567 mV, 564 mV, 560 mV, 558 mV, 555 mV, 552 mV, 550 mV, 549 mV, 545 mV, 542 mV, 540 mV, 535 mV, 532 mV, 530 mV, 525 mV, 522 mV, 520 mV, 518 mV, 515 mV, 509 mV, 505 mV, 503 mV, 500 mV, 495 mV, 490 mV, 485 mV, 480 mV, 475 mV, or 470 mV, etc. Preferably, the silver vanadium oxide cathode material has an average overpotential < 550 mV at 20 mA / cm2. 2 at 40 mA / cm2, an average overpotential < 330 mV. 2 at 40 mA / cm2, an average overpotential < 550 mV.

[0011] The following is a preferred technical solution of the present application, but not as a limitation of the technical solutions provided by the present application, through the following technical solutions, the technical purpose and beneficial effects of the present application can be better achieved and realized.

[0012] As a preferred technical solution of the present application, the silver vanadium oxide cathode material has a specific capacity > 270 mAh / g at 0.05 C constant current discharge to 2 V, for example, it can be 271 mAh / g, 273 mAh / g, 275 mAh / g, 278 mAh / g, 280 mAh / g, 283 mAh / g, 285 mAh / g, 288 mAh / g, 290 mAh / g, 292 mAh / g, 295 mAh / g, 298 mAh / g, or 300 mAh / g, etc.

[0013] As a preferred embodiment of the present invention, the primary particles of the silver vanadium oxide cathode material are rod-shaped with a diameter of 0.5–2 μm, such as 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, or 2 μm; a length of 5–20 μm, such as 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, or 20 μm; an aspect ratio of 2.5–100, such as 2.5, 5, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100; and a cross-sectional porosity of 5%–20%, such as 5%, 8%, 10%, 12%, 14%, 16%, 18%, or 20%.

[0014] Preferably, the loose packing density of the silver vanadium oxide cathode material is 1–2 g / cm³. 3 For example, 1g / cm 3 1.2g / cm 3 1.4g / cm 3 1.6g / cm 3 1.8g / cm 3 or 2g / cm 3 etc.; tap density is 1.5–3.5 g / cm³. 3 For example, 1.5g / cm 3 1.8g / cm 3 2g / cm 3 2.2g / cm 3 2.5g / cm 3 2.8g / cm 3 2.9g / cm 3 3g / cm 3 3.3g / cm 3 Or 3.5g / cm 3 True density is 4-5 g / cm³ 3 For example, 4g / cm 3 4.2g / cm 3 4.4 g / cm 3 4.6g / cm 3 4.8g / cm 3 or 5g / cm 3 wait.

[0015] Secondly, this aspect provides a method for preparing the silver vanadium oxide cathode material described in the first aspect, the method comprising the following steps:

[0016] The silver source and the vanadium source were mixed in the liquid phase and then dried at temperature T1 to obtain a dried mixture;

[0017] The dry mixture is tested for gas generation temperature T2 by differential scanning calorimetry;

[0018] The dry mixture is pre-calcined at a temperature T3 to obtain a pre-calcined material; the pre-calcined material is subjected to first solid-phase grinding to obtain a first ground material;

[0019] The first ground material is subjected to main calcination at a temperature T4 to obtain a main calcined material; the main calcined material is subjected to second solid-phase grinding to obtain a silver vanadium oxide positive electrode material;

[0020] T1 < T2 < T3 < T4.

[0021] To meet the discharge requirements when applied to ICD, shorten the capacitor charging time, suppress the growth of battery internal resistance and alleviate the voltage delay phenomenon, it is crucial to optimize the structure and parameters of the battery active material. The present application proposes a preparation method for synthesizing silver vanadium oxide positive electrode material by high-temperature solid-phase method with the introduction of a low-temperature pre-calcination link. The preparation method is based on the DSC results of the wet mixed and dried material of silver source and vanadium source to set the pre-calcination temperature, so as to improve and solve the problems of slow gas release and poor diffusion caused by high pressure in the furnace, and difficult to discharge in time during rapid heating to high temperature, thereby effectively promoting the effective discharge of gas at low temperature, fully promoting the forward reaction, effectively reducing the risk of lattice distortion, ensuring the purity and structural integrity of the product, and finally improving the discharge performance.

[0022] Specifically, in the process of solid-phase synthesis reaction, the physical contact efficiency and diffusion kinetics between reactants directly determine the chemical uniformity and crystal structure integrity of the product, and these two factors are the core factors affecting the high-rate pulse performance of the positive electrode material. The traditional solid-phase method generally faces problems such as limited reaction interface, low ion migration rate, and local component segregation, which easily leads to the existence of unreacted residual phase, lattice defects or composition gradient in the product, and further causes the polarization intensification, capacity attenuation and voltage delay phenomenon in the electrochemical process. To solve this systematic problem, the preparation method of the present application is designed as a segmented heat treatment process of "low-temperature pre-calcination-intermediate grinding-high-temperature final calcination". Among them, the pre-calcination stage is based on the decomposition window determined by DSC to promote the initial nucleation and gas release of the raw material under mild conditions, and the intermediate mechanical grinding is used to forcibly destroy the sintered agglomerates formed in the early stage to realize the dynamic update of the reaction interface; finally, high-temperature crystallization is carried out under an optimized temperature rising program to ensure the ordered assembly of vanadium oxide polyhedron and silver ion. This "crushing-low temperature pre-burning-grinding-high temperature final burning" cycle strengthening mechanism not only effectively overcomes the inherent mass transfer resistance of solid-phase reaction, but also successfully synthesizes silver vanadium oxide positive electrode material with high stoichiometric consistency and long-range ordered and complete crystal structure by inhibiting lattice distortion and composition segregation caused by local overheating.

[0023] The preparation method effectively promotes the preferred growth of specific crystal faces while significantly improving the crystallinity and integrity of silver vanadium oxide crystals, can simultaneously reduce the specific surface area (BET) of the material to a level of 0.6-1.5 m 2 / g, and produces a triple synergistic effect: ① The optimized crystal channel structure effectively accelerates the migration dynamics of lithium ions; ② The densified surface effectively inhibits the dissociation of vanadate groups caused by electrolyte corrosion, greatly reducing vanadium dissolution; ③ The concentration polarization effect during high-rate pulse discharge is effectively reduced, significantly improving the voltage hysteresis phenomenon. Ultimately, a silver vanadium oxide positive electrode material with high specific capacity, excellent rate characteristics, and stability is obtained, fully meeting the stringent requirements of implantable medical devices for pulse discharge performance of power sources.

[0024] As a preferred technical solution of the present application, the silver source includes at least one of Ag, AgI, Ag2O, AgNO3, AgNO2, Ag2CO3, or AgVO3.

[0025] Preferably, the vanadium source includes V2O5 and / or NH4VO3.

[0026] Preferably, the amount of the silver source and the vanadium source is controlled according to a molar ratio of silver elements to vanadium elements, such as 1:1.98, 1:1.985, 1:1.99, 1:1.995, 1:2, 1:2.005, 1:2.01, 1:2.015, or 1:2.02, etc.

[0027] As a preferred technical solution of the present application, the silver source and the vanadium source are respectively pre-crushed to a particle size D 50 ≤5 μm, such as 5 μm, 4.8 μm, 4.5 μm, 4.2 μm, 4 μm, 3.7 μm, 3.5 μm, 3.2 μm, 3 μm, 2.8 μm, 2.5 μm, 2.2 μm, 2 μm, 1.8 μm, 1.5 μm, 1.2 μm, 1 μm, or 0.5 μm, etc.

[0028] Preferably, the dispersion medium in the liquid phase includes water.

[0029] Preferably, the process of mixing the silver source and the vanadium source in the liquid phase includes: mixing the silver source and the vanadium source with the dispersion medium respectively to obtain a silver source dispersion liquid and a vanadium source dispersion liquid, and then mixing and stirring the silver source dispersion liquid and the vanadium source dispersion liquid.

[0030] Preferably, in the silver source dispersion liquid, the mass ratio of the silver source to the dispersion medium is (6-10):1, such as 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1, etc.

[0031] Preferably, the mass ratio of vanadium source to dispersion medium in the vanadium source dispersion is (6-10):1, such as 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1, etc.

[0032] Preferably, the rotation speed of the mixing and stirring is 300-800 rpm, such as 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, or 800 rpm, etc., and the time is 2-6 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, or 6 h, etc.

[0033] Preferably, after the mixing in the liquid phase, the wet mixed precipitate is obtained by solid-liquid separation before the drying, and the wet mixed precipitate is subjected to the drying to obtain the dry mixture.

[0034] As a preferred technical solution of the present application, T1≤100℃, further preferably 60℃≤T1≤90℃, such as 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, or 90℃, etc.

[0035] Preferably, the pre-calcination and the main calcination are both carried out in an oxygen-containing atmosphere, preferably in air.

[0036] Preferably, the heating rate of the pre-calcination and the main calcination is 1-15℃ / min, such as 1℃ / min, 3℃ / min, 5℃ / min, 8℃ / min, 10℃ / min, 12℃ / min, or 15℃ / min, etc.

[0037] Preferably, 0℃≤T3-T2≤30℃, such as the difference T3-T2 can be 0℃, 3℃, 5℃, 8℃, 10℃, 13℃, 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, or 30℃, preferably 15℃≤T3-T2≤25℃, further preferably 20℃.

[0038] Preferably, 180℃≤T2≤330℃, such as T2 can be 180℃, 190℃, 200℃, 220℃, 240℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, or 330℃, etc.

[0039] Preferably, 210℃≤T3≤350℃, such as T3 can be 210℃, 230℃, 250℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, or 350℃, etc.

[0040] Preferably, 400℃≤T4≤600℃, for example, T4 can be 400℃, 420℃, 450℃, 480℃, 500℃, 530℃, 550℃, 580℃ or 600℃, etc., preferably 450℃≤T4≤550℃, further preferably 500℃.

[0041] Preferably, the pre-calcination time is 5-35h, for example, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 22h, 25h, 28h, 30h, 32h or 35h, etc., preferably 5-12h.

[0042] Preferably, the main calcination time is 5-35h, for example, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 22h, 25h, 28h, 30h, 32h or 35h, etc., preferably 20-35h.

[0043] As a preferred technical solution of the present application, the preparation method further comprises: after the first second solid phase grinding, a second grinding material is obtained; the second grinding material is sequentially repeated at least once with the main calcination and the second solid phase grinding; after the last second solid phase grinding, the silver vanadium oxide positive electrode material is obtained.

[0044] Preferably, the preparation method is performed 1-5 times of the main calcination, for example, 1 time, 2 times, 3 times, 4 times or 5 times, etc., preferably 2 times.

[0045] Preferably, the temperature of the last main calcination is the same as that of the previous main calcination.

[0046] Preferably, the total time of the pre-calcination and all the main calcinations is 35-60h, for example, 35h, 38h, 40h, 43h, 45h, 48h, 50h, 52h, 54h, 56h, 58h or 60h, etc.

[0047] Preferably, the modes of the first solid phase grinding and the second solid phase grinding both include high-energy ball milling, the rotation speed of the high-energy ball milling is 300-500rpm, for example, 300rpm, 330rpm, 350rpm, 380rpm, 400rpm, 420rpm, 450rpm, 480rpm or 500rpm, etc., and the time is 2-4h, for example, 2h, 2.3h, 2.5h, 2.8h, 3h, 3.3h, 3.5h, 3.8h or 4h, etc.

[0048] It should be noted that the preparation method can significantly improve the crystallinity and integrity of silver vanadium oxide crystals, effectively promote the preferential growth of specific crystal faces, and simultaneously achieve the reduction of the specific surface area (BET) of the material, but the specific surface area should not be too low. The high-temperature main calcination process in the preparation method can reduce the BET of the material, but if the calcination temperature is too high, the material will be prone to collapse and have poor long-term stability. The solid-phase grinding process in the preparation method can increase the BET of the material, but insufficient grinding will lead to poor dispersion and uniformity of the material. Therefore, the calcination and grinding processes should be considered to ensure that the BET of the obtained material is not too small.

[0049] In a third aspect, the present application provides a battery containing the silver vanadium oxide positive electrode material of the first aspect.

[0050] It should be noted that, for example, in the battery, the negative electrode can use metal lithium or Li-Al, Li-Sn, Li-Pb, etc. lithium alloy; the solvents used as non-aqueous electrolyte include γ-butyrolactone (γ-GBL), propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and dimethyl ether (DME); the supporting electrolyte constituting the non-aqueous electrolyte includes lithium hexafluoroarsenate (LiAsF6), lithium hexafluorophosphate (LiPF6), lithium bisoxalate borate (LiBOB), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium difluoro oxalate borate (LiODFB), lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium difluorophosphate (LiPO2F2), and lithium tetrafluoro oxalate phosphate (LiFOP); the positive electrode includes 80% to 99% by weight of positive electrode active material, and the positive electrode active material can be all the silver vanadium oxide positive electrode material. The positive electrode can be manufactured by mixing silver vanadium oxide positive electrode material, conductive agent, and binder in a planetary ball mill. The positive electrode prepared as described above can be in the form of one or more electrode plates associated with at least one or more negative electrode materials, or in the form of a strip wound in a wound structure with the corresponding strip of negative electrode material. In addition, the positive electrode current collector, negative electrode current collector, shell, separator, etc. constituting the battery can all use materials commonly used in the field, and the shape and size are not limited. In addition, the battery shape can adopt coin shape, needle shape, cylindrical shape, square shape, special shape, etc., and is not specifically limited, and should be reasonably selected according to actual needs.

[0051] In a fourth aspect, the present application provides a power device containing the battery of the third aspect.

[0052] As a preferred technical solution of the present application, the power device includes an implantable cardioverter-defibrillator.

[0053] Preferably, the battery applied in the implantable cardioverter-defibrillator is a primary battery.

[0054] It should be noted that due to the limitation of the length and in order to avoid redundancy, the present application does not exhaustively list all the point values in the above numerical range, but also is not limited to the listed values, and other unlisted values in the above numerical range are also applicable.

[0055] Compared with the prior art, the present application has at least the following beneficial effects:

[0056] The present application provides a silver vanadium oxide positive electrode material with a small specific surface area by BET windowing control, which is in the range of 0.6-1.5 m 2 / g, can fully realize the reduction or avoidance of the effects of internal resistance growth and voltage delay, and can realize an average hysteresis voltage of <350 mV at a 20 mA / cm 2 instantaneous current. 2 The average hysteresis voltage is <580 mV at a 40 mA / cm 2 instantaneous current.

[0057] The preparation method of the present application is designed based on the decomposition window determined by DSC, and low-temperature pre-calcination is performed, followed by intermediate grinding and high-temperature final calcination to form a segmented heat treatment process, which effectively overcomes the inherent mass transfer resistance of solid-phase reaction, suppresses the lattice distortion and composition segregation caused by local overheating, significantly improves the crystallinity and integrity of silver vanadium oxide crystals, effectively promotes the preferential growth of specific crystal faces, and simultaneously realizes the reduction of the specific surface area (BET) of the material, and can reach a specific level of 0.6-1.5 m 2 / g. In addition, the optimization of the crystal structure also produces a triple synergistic effect: ① the optimized crystal channel structure effectively accelerates the lithium ion migration dynamics; ② the densified surface effectively suppresses the dissociation of vanadate groups caused by electrolyte erosion, greatly reducing the vanadium dissolution phenomenon; ③ effectively reducing the concentration polarization effect during high-rate pulse discharge, significantly improving the voltage hysteresis phenomenon. Ultimately, a silver vanadium oxide positive electrode material with high specific capacity, excellent rate characteristics and stability is obtained, which fully meets the stringent requirements of implantable medical devices for power pulse discharge performance. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is the SEM test graph of the silver vanadium oxide positive electrode material obtained in Example 1.

[0059] Figure 2 is the specific capacity-voltage curve test graph of the battery containing the silver vanadium oxide obtained in Example 1.

[0060] Figure 3 is the pulse time-voltage curve test graph of the battery containing the silver vanadium oxide obtained in Example 1. DETAILED DESCRIPTION

[0061] The technical solutions of the present application are further illustrated by specific embodiments.

[0062] Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations on the present application.

[0063] Embodiment 1

[0064] The present embodiment provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 , and the preparation method of the silver vanadium oxide positive electrode material comprises the following steps:

[0065] S1. Take silver source AgNO3 and vanadium source V2O5 according to the molar ratio of silver element to vanadium element is 1:2, and the silver source and the vanadium source are respectively pre-crushed to particle size D 50 2.3 μm and 2.8 μm;

[0066] S2. The silver source and the vanadium source are mixed with the dispersion medium water respectively, the mass ratio of the silver source to the dispersion medium is 8:1 to obtain a silver source dispersion liquid, the mass ratio of the vanadium source to the dispersion medium is 8:1 to obtain a vanadium source dispersion liquid, and then the silver source dispersion liquid and the vanadium source dispersion liquid are mixed and stirred, the stirring speed is 500 rpm, and the stirring time is 4 h, and the liquid is left overnight; After the liquid phase mixing is completed, solid-liquid separation is first carried out to obtain a wet mixed precipitate, and the wet mixed precipitate is dried at T1 = 70℃ to obtain a dry mixture;

[0067] S3. The dry mixture is tested by differential scanning calorimetry to obtain a gas production temperature T2 = 280℃;

[0068] S4. The dry mixture is placed on a porcelain boat and put into a box-type atmosphere furnace, and precalcination is carried out at T3 = 300℃ under air atmosphere at a heating rate of 10℃ / min for 16 h, and after natural cooling, a precalcined material is obtained; The precalcined material is subjected to first solid phase grinding, which is high-energy ball milling at 400 rpm for 3 h, to obtain a first ground material;

[0069] S5. The first ground material is placed on a porcelain boat and put into a box-type atmosphere furnace, and main calcination is carried out at T4 = 500℃ under air atmosphere at a heating rate of 10℃ / min to obtain a main calcined material; The main calcined material is subjected to second solid phase grinding, which is high-energy ball milling at 400 rpm for 3 h, to obtain a second ground material, and the second ground material is subjected to the main calcination and the second solid phase grinding again once to obtain a silver vanadium oxide positive electrode material.

[0070] Embodiment 2

[0071] The embodiment provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the silver source from AgNO3 to Ag2CO3 in step S1, the gas production temperature T2 of the dry mixture measured in step S3 is 200 DEG C, the precalcination temperature in step S4 is adjusted from T3=300 DEG C to T3=220 DEG C, and other conditions are completely same with those in example 1.

[0072] Example 3

[0073] The embodiment provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the vanadium source from V2O5 to NH4VO3 in step S1, the gas production temperature T2 of the dry mixture measured in step S3 is 280 DEG C, the precalcination temperature T3 in step S4 is kept unchanged, and other conditions are completely same with those in example 1.

[0074] Example 4

[0075] The embodiment provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the silver source from AgNO3 to Ag2CO3, and adjusts the vanadium source from V2O5 to NH4VO3 in step S1, the gas production temperature T2 of the dry mixture measured in step S3 is 200 DEG C, the precalcination temperature in step S4 is adjusted from T3=300 DEG C to T3=220 DEG C, and other conditions are completely same with those in example 1.

[0076] Comparative example 1

[0077] The comparative example provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the precalcination temperature from T3=300 DEG C to T3=260 DEG C in step S4, and other conditions are completely same with those in example 1.

[0078] Comparative example 2

[0079] The comparative example provides a silver vanadium oxide positive electrode material, the silver vanadium oxide positive electrode material is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the precalcination temperature from T3=300 DEG C to T3=280 DEG C in step S4, and other conditions are completely same with those in example 1.

[0080] Comparative Example 3

[0081] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the pre-calcination temperature from T3 = 300°C to T3 = 360°C in step S4, and other conditions are completely the same as those in Example 1.

[0082] Comparative Example 4

[0083] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the pre-calcination temperature from T3 = 300°C to T3 = 500°C in step S4, and other conditions are completely the same as those in Example 1.

[0084] Comparative Example 5

[0085] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the main calcination temperature from T4 = 500°C to T4 = 600°C in step S5, and other conditions are completely the same as those in Example 1.

[0086] Comparative Example 6

[0087] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material adjusts the main calcination temperature from T4 = 500°C to T4 = 400°C in step S5, and other conditions are completely the same as those in Example 1.

[0088] Comparative Example 7

[0089] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11 The preparation method of the silver vanadium oxide positive electrode material only performs one main calcination and one second solid-phase grinding in step S5, and does not repeat, and the second grinding material obtained by the first second solid-phase grinding is used as the silver vanadium oxide positive electrode material, and other conditions are completely the same as those in Example 1.

[0090] Comparative Example 8

[0091] This comparative example provides a silver vanadium oxide positive electrode material, which is Ag2V4O 11, the preparation method of the silver vanadium oxide positive electrode material is repeated three times of main calcination and second solid phase grinding in step S5, that is, the second grinding material obtained by the first second solid phase grinding is repeated twice of the main calcination and the second solid phase grinding, and other conditions are completely same as those in example 1.

[0092] Characterization and test:

[0093] I. Specific surface area test: the specific surface area analyzer (BELSORP MAX) is used for testing, and the repeatability is ≤±1.5%. The BET equation is based on the nitrogen adsorption isotherm (P / P0=0.05-0.30), and the monolayer adsorption amount V m is obtained by the slope and intercept. m ·N A ·σ / M· V std ; wherein, N A is the Avogadro constant, σ is the cross-sectional area of the adsorbed molecule, and V std is the molar volume of the standard state gas.

[0094] II. Morphology and size test: the electron scanning electron microscope (Zeiss Gemini 500) is used for testing, and the repeatability is >0.2% by the high-performance field emission scanning electron microscope. Figure 1 is the SEM test diagram of the silver vanadium oxide material obtained in example 1, and it can be seen from the diagram that the synthesized silver vanadium oxide positive electrode material is a rod-like morphology with a diameter of about 1 μm and a length of about 15 μm, and the aspect ratio is about 15.

[0095] III. True density test: the full-automatic true density instrument (TD-6700) is used for testing, and the precision is high (repeatability ±0.015%). The calculation formula is ρ=m / V 骨架 . The bulk density of the silver vanadium oxide positive electrode material synthesized in the example is 1-2 g / cm 3 , the tap density is 1.5-3.5 g / cm 3 , and the true density is 4-5 g / cm 3 .

[0096] IV. Electrochemical performance test: the discharge is carried out by using the new Wei discharge device (CT-4008T), and the voltage / current precision is ±0.05%-±0.1% FS.

[0097] The silver vanadium oxide positive electrode material obtained in the example and the comparative example is mixed with the conductive agent acetylene black and the binder polyvinylidene fluoride according to the mass ratio of 90:5:5, and then rolled and pressed into a positive electrode sheet (the area density is 180 g / m 2);the metal lithium sheet is used as the negative electrode, the porous polypropylene paper is used as the diaphragm, the electrolyte contains 1M of LiClO4, the solvent is ethylene carbonate (EC) and diethyl carbonate (DEC), and the soft package laminated battery is assembled in a glove box filled with high-purity argon;

[0098] The ICD working condition is simulated, and the capacity and pulse test are carried out: the capacity test is carried out by constant current discharge under the current of 0.05C; the pulse test is carried out by pulse discharge under the current density of 20mA / cm 2 and 40mA / cm 2 , specifically, discharging for 10s, standing for 15s, and each four groups are a cycle, and the standing time is 3h; wherein, the average hysteresis voltage difference △UAVG = the voltage drop of the pulse current applied to the battery = the background voltage - the minimum pulse voltage. Figure 2 is the specific capacity-voltage curve test diagram of the battery containing the silver vanadium oxide obtained in Example 1, and it can be seen from the diagram that the gram capacity is 275mAh / g when discharged to 2V; Figure 3 is the pulse time-voltage curve test diagram of the battery containing the silver vanadium oxide obtained in Example 1, and it can be calculated from the diagram that the average hysteresis voltage is 306mV under the instantaneous current of 20mA / cm 2 ; and the average hysteresis voltage is 520mV under the instantaneous current of 40mA / cm 2 .

[0099] The above test results are recorded in Table 1.

[0100] Table 1

[0101]

[0102] It can be seen from Table 1 that:

[0103] In the solid phase synthesis process of the silver vanadium oxide positive electrode material prepared by the preparation method, the synergistic control of the decomposition kinetics of raw materials and the crystallization temperature is the core factor for determining the structural uniformity and electrochemical performance of the material. The optimal low-temperature pre-calcination temperature of the material is set to be about 20℃ higher than the DSC gas production temperature, which can maximize the elimination of the gas generated by the reaction, guarantee the oxidizing atmosphere of the synthesized material, and synthesize the material with the optimal electrical performance. Specifically, under the catalysis of the vanadium source, the decomposition temperature of the silver-containing precursor is reduced, the initial decomposition temperature of silver nitrate and vanadium pentoxide is about 280℃, and the optimal calcination temperature is set to be 300℃; the initial decomposition temperature of silver carbonate and vanadium pentoxide is about 200℃, and the optimal calcination temperature is set to be 220℃; the initial decomposition temperature of silver nitrate and ammonium vanadate is about 280℃, and the optimal calcination temperature is set to be 300℃; and the initial decomposition temperature of silver carbonate and ammonium vanadate is about 200℃, and the optimal calcination temperature is set to be 220℃. By further optimizing the preparation method, the silver vanadium oxide with the chemical formula of Ag2V4O11 Specific surface area: 0.6-1.5 m 2 Average hysteresis voltage < 330 mV at 20 mA / cm 2 Average hysteresis voltage < 550 mV at 40 mA / cm 2 Silver vanadium oxide positive electrode material having an average hysteresis voltage < 550 mV at 40 mA / cm.

[0104] The above describes the preferred embodiments of the present application in detail, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0105] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not describe various possible combinations again.

[0106] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. A silver vanadium oxide cathode material, characterized in that, The chemical formula of the silver vanadium oxide cathode material is Ag₂V₄O₄. 11 Its specific surface area is 0.6–1.5 m². 2 / g; at 20mA / cm 2 Under instantaneous current, the average hysteresis voltage is <350mV; at 40mA / cm 2 Under instantaneous current, the average hysteresis voltage is <580mV.

2. The silver vanadium oxide cathode material according to claim 1, characterized in that, The silver vanadium oxide cathode material operates at 20 mA / cm². 2 Under instantaneous current, the average hysteresis voltage is <330mV; at 40mA / cm 2 Under instantaneous current, the average hysteresis voltage is <550mV; Preferably, the specific capacity of the silver vanadium oxide cathode material discharged at 0.05C constant current to 2V is >270mAh / g; Preferably, the primary particles of the silver vanadium oxide cathode material have a rod-like morphology, with a diameter of 0.5–2 μm, a length of 5–20 μm, an aspect ratio of 2.5–100, and a cross-sectional porosity of 5%–20%. Preferably, the loose packing density of the silver vanadium oxide cathode material is 1–2 g / cm³. 3 The tap density is 1.5–3.5 g / cm³. 3 The true density is 4-5 g / cm³. 3 .

3. A method for preparing the silver vanadium oxide cathode material according to claim 1 or 2, characterized in that, The preparation method includes the following steps: The silver source and the vanadium source were mixed in the liquid phase and then dried at temperature T1 to obtain a dried mixture; The gas generation temperature T2 of the dried mixture was determined using differential scanning calorimetry. The dried mixture was pre-calcined at temperature T3 to obtain a pre-calcined material; The pre-calcined material is subjected to a first solid-phase grinding process to obtain a first grinding material; The first grinding material was calcined at temperature T4 to obtain the calcined material. The main calcined material is subjected to a second solid-phase grinding process to obtain a silver vanadium oxide cathode material. Where T1 < T2 ≤ T3 < T4.

4. The method for preparing the silver vanadium oxide cathode material according to claim 3, characterized in that, The silver source includes at least one of Ag, AgI, Ag2O, AgNO3, AgNO2, Ag2CO3, or AgVO3; Preferably, the vanadium source includes V2O5 and / or NH4VO3.

5. The method for preparing the silver vanadium oxide cathode material according to claim 3 or 4, characterized in that, Before the silver source and vanadium source are mixed in the liquid phase, they are respectively crushed to a particle size D. 50 ≤5μm; Preferably, the dispersion medium in the liquid phase includes water; Preferably, the process of mixing the silver source and the vanadium source in the liquid phase includes: mixing the silver source and the vanadium source with a dispersion medium respectively to obtain a silver source dispersion and a vanadium source dispersion, and then mixing and stirring the silver source dispersion and the vanadium source dispersion. Preferably, in the silver source dispersion, the mass ratio of silver source to dispersion medium is (6-10):1; Preferably, in the vanadium source dispersion, the mass ratio of vanadium source to dispersion medium is (6-10):1; Preferably, the mixing and stirring speed is 300-800 rpm, and the time is 2-6 hours; Preferably, after mixing in the liquid phase and before drying, solid-liquid separation is performed to obtain a wet mixed precipitate, and the wet mixed precipitate is dried to obtain a dry mixture.

6. The method for preparing the silver vanadium oxide cathode material according to any one of claims 3-5, characterized in that, The T1 ≤ 100℃ is more preferably 60℃ ≤ T1 ≤ 90℃; Preferably, both the pre-calcination and the main calcination are carried out in an oxygen-containing atmosphere, and more preferably in air; Preferably, the heating rate of both the pre-calcination and the main calcination is 1-15℃ / min; Preferably, 0℃≤T3-T2≤30℃, and more preferably 15℃≤T3-T2≤25℃; Preferably, 180℃≤T2≤330℃; Preferably, 210℃≤T3≤350℃; Preferably, 400℃≤T4≤600℃, and more preferably 450℃≤T4≤550℃; Preferably, the pre-calcination time is 5–35 h, more preferably 5–12 h; Preferably, the primary calcination time is 5 to 35 hours, more preferably 20 to 35 hours.

7. The method for preparing the silver vanadium oxide cathode material according to any one of claims 3-6, characterized in that, The preparation method further includes: after the first second solid-phase grinding, a second abrasive is obtained; the second abrasive is subjected to the main calcination and the second solid-phase grinding at least once; after the last second solid-phase grinding, the silver vanadium oxide cathode material is obtained. Preferably, the preparation method involves 1 to 5 main calcinations, more preferably 2 times; Preferably, the temperature of the subsequent main calcination is the same as the temperature of the previous main calcination; Preferably, the total time for the pre-calcination and all the main calcinations is 35 to 60 hours; Preferably, both the first solid-phase grinding and the second solid-phase grinding methods include high-energy ball milling, wherein the high-energy ball milling speed is 300-500 rpm and the time is 2-4 hours.

8. A battery, characterized in that, The cathode material comprising the silver vanadium oxide as described in claim 1 or 2.

9. An electrical device, characterized in that, It contains the battery as described in claim 8.

10. The electrical appliance according to claim 9, characterized in that, The electrical device includes an implantable cardioverter defibrillator.

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