Battery material, preparation method and application thereof, pole piece and symmetrical battery

Abstract

The present invention provides a battery material and its preparation method and application, a pole piece and a symmetrical battery, which relate to the field of battery technology. The battery material provided by the present invention includes Na (1+2x+y) Mn x V y Ti (2‑x‑y) (PO4)3 material and carbon, wherein 0<x≤1, 0<y≤1.8, x+y<2; carbon coated on Na (1+2x+y) Mn x V y Ti (2‑x‑y) The surface of a (PO4)3 material. This battery material can serve as both the positive and negative electrodes. Assembling a symmetrical battery using this material avoids mismatches in the physical properties of the positive and negative electrode materials. The resulting symmetrical battery has high specific capacity, long cycle life, and excellent safety.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery material, a preparation method and application thereof, a pole piece and a symmetrical battery. Background Art

[0002] The performance of a full battery is influenced by both the positive and negative electrodes, with the performance being determined by the worse electrode. The mismatch in the physical properties of the positive and negative electrode materials is the primary reason for the difficulty in improving full battery performance. Symmetrical batteries, with identical active materials for the positive and negative electrodes, offer advantages such as high reaction rates, high power, and low cost, making them a promising next-generation energy storage device. However, current research on active materials for symmetrical batteries is insufficient, and existing cathode materials for symmetrical batteries generally suffer from low specific capacity and short cycle life.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The first object of the present invention is to provide a battery material to solve the above technical problems.

[0005] The second object of the present invention is to provide a method for preparing the above-mentioned battery material.

[0006] The third object of the present invention is to provide application of the above-mentioned battery material in batteries.

[0007] A fourth object of the present invention is to provide a pole piece.

[0008] A fifth object of the present invention is to provide a symmetrical battery.

[0009] In order to achieve the above objectives, the following technical solutions are adopted:

[0010] In a first aspect, the present invention provides a battery material, wherein the battery material comprises Na (1+2x+y) Mn x V y Ti (2-x-y) (PO4)3 material and carbon, wherein 0<x≤1, 0<y≤1.8, x+y<2;

[0011] The carbon is coated on Na (1+2x+y) Mn x V y Ti (2-x-y) The surface of (PO4)3 material.

[0012] As a further technical solution, the mass proportion of carbon in the battery material is 8%-16%.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned battery material, comprising the following steps: using a complexing agent as a carbon source, mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source and a titanium source to form a gel, and then drying and sintering it under a protective atmosphere in sequence to prepare the battery material.

[0014] As a further technical solution, the step of using a complexing agent as a carbon source and mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source and a titanium source to form a gel comprises:

[0015] a. mixing a complexing agent, a vanadium source, a manganese source, a sodium source and a phosphorus source, and performing a complexing reaction;

[0016] b. Add the solution containing the titanium source dropwise to the solution after the complexation reaction in step a, and heat in a water bath to form a gel.

[0017] As a further technical solution, the water bath heating temperature is 75-85°C.

[0018] As a further technical solution, the complexing agent includes citric acid;

[0019] The vanadium source includes at least one of vanadium pentoxide or ammonium metavanadate;

[0020] The manganese source includes at least one of manganese acetate, manganese nitrate or manganese acetylacetonate;

[0021] The sodium source includes at least one of sodium acetate, sodium carbonate, sodium nitrate, sodium dihydrogen phosphate or sodium hydroxide;

[0022] The phosphorus source includes at least one of phosphoric acid or ammonium dihydrogen phosphate;

[0023] The titanium source includes at least one of tetraisopropyl titanate, tetrabutyl titanate or dihydroxybis(ammonium lactate) titanium.

[0024] As a further technical solution, the sintering temperature is 700-800°C;

[0025] The sintering time is 6-10 hours.

[0026] In a third aspect, the present invention provides the use of the above-mentioned battery material in a battery.

[0027] In a fourth aspect, the present invention provides a pole piece, wherein the active material of the pole piece includes the battery material.

[0028] In a fifth aspect, the present invention provides a symmetrical battery, wherein the positive electrode plate and the negative electrode plate of the symmetrical battery are both the aforementioned plates.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The battery material provided by the present invention can be used as both positive and negative electrodes: when acting as a negative electrode, it can stimulate Ti 4+ / Ti 3+ (2.1V), V 3+ / V 2+ (1.6V) reaction; when acting as a positive electrode, it uses a higher potential V 3+ / V 4+ (3.4V), Mn 2+ / Mn 3+ (3.5V), V 4+ / V 5+ (3.9V) electrode pair. The positive and negative electrodes can be prepared using the same line, which helps reduce costs.

[0031] 2. The use of this material to assemble a symmetrical battery avoids the mismatch of the physical properties of the positive and negative electrode materials. The prepared symmetrical battery can achieve a specific capacity of 86 mAh g -1 , the cycle life can reach more than 1000 cycles.

[0032] 3. When the battery material provided by the present invention is used as a negative electrode material, since the average potential is much higher than the deposition potential of Na metal, sodium precipitation can be reduced, making the battery safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is the XRD pattern of the battery material of Example 1 of the present invention;

[0035] Figure 2 The charge and discharge curves of the half-cell assembled with the battery material of Example 1;

[0036] Figure 3 The cycling performance of the symmetrical battery assembled using the battery material of Example 1. DETAILED DESCRIPTION

[0037] Below in conjunction with embodiment and example, embodiment of the present invention is described in detail, but those skilled in the art will appreciate that the following embodiment and example are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise all fall within the scope of protection of the present invention. Unspecified conditions are carried out according to the conditions of normal conditions or manufacturer's recommendations. Reagents used or instruments not specified by the manufacturer are conventional products that can be purchased commercially.

[0038] In a first aspect, the present invention provides a battery material, wherein the battery material comprises Na (1+2x+y) Mn x V y Ti (2-x-y) (PO4)3 material and carbon, wherein 0<x≤1, 0<y≤1.8, x+y<2;

[0039] The carbon is coated on Na (1+2x+y) Mn x V y Ti (2-x-y) The surface of (PO4)3 material.

[0040] The battery material provided by the present invention can be used as both positive and negative electrodes: when it acts as a negative electrode, it can stimulate Ti 4+ / Ti 3+ (2.1V), V 3 + / V 2+ (1.6V) reaction; when acting as a positive electrode, it uses a higher potential V 3+ / V 4+ (3.4V), Mn 2+ / Mn 3+ (3.5V), V 4+ / V 5+ (3.9V) electrode pair. The positive and negative electrodes can be prepared using the same line, which helps reduce costs. The use of this material to assemble symmetrical batteries avoids the mismatch in the physical properties of the positive and negative electrode materials. The prepared symmetrical battery can achieve a specific capacity of 86mAh g -1 , the cycle life can reach more than 1000 cycles. In addition, when the battery material provided by the present invention is used as the negative electrode material, since the average potential is much higher than the deposition potential of Na metal, sodium precipitation can be reduced, making the battery safer.

[0041] In some optional embodiments, the mass proportion of carbon in the battery material is 8%-16%.

[0042] In a second aspect, the present invention provides a method for preparing the above-mentioned battery material, comprising the following steps: using a complexing agent as a carbon source, mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source and a titanium source to form a gel, and then drying and sintering it under a protective atmosphere in sequence to prepare the battery material.

[0043] The preparation method is simple and efficient, and the prepared battery material can be used for the preparation of symmetrical batteries.

[0044] In some optional embodiments, the step of using a complexing agent as a carbon source and mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source, and a titanium source to form a gel comprises:

[0045] a. mixing a complexing agent, a vanadium source, a manganese source, a sodium source and a phosphorus source, and performing a complexing reaction;

[0046] b. Add the solution containing the titanium source dropwise to the solution after the complexation reaction in step a, and heat in a water bath to form a gel.

[0047] In some optional embodiments, the temperature of the water bath heating may be, for example, but not limited to, 75°C, 80°C or 85°C.

[0048] In some optional embodiments, the complexing agent includes but is not limited to citric acid;

[0049] The vanadium source includes but is not limited to at least one of vanadium pentoxide or ammonium metavanadate;

[0050] The manganese source includes but is not limited to at least one of manganese acetate, manganese nitrate or manganese acetylacetonate;

[0051] The sodium source includes but is not limited to at least one of sodium acetate, sodium carbonate, sodium nitrate, sodium dihydrogen phosphate or sodium hydroxide;

[0052] The phosphorus source includes but is not limited to at least one of phosphoric acid or ammonium dihydrogen phosphate;

[0053] The titanium source includes, but is not limited to, at least one of tetraisopropyl titanate, tetrabutyl titanate, or dihydroxybis(ammonium lactate) titanium.

[0054] In some optional embodiments, the titanium source is dissolved in isopropanol or ethanol to obtain the solution containing the titanium source.

[0055] In some optional embodiments, the sintering temperature may be, for example, but not limited to, 700° C., 720° C., 740° C., 760° C., 780° C., or 800° C.;

[0056] The sintering time may be, for example, but not limited to, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours.

[0057] The complexing agent is carbonized by sintering to generate battery materials.

[0058] In a third aspect, the present invention provides the use of the above-mentioned battery material in a battery.

[0059] The battery materials provided by the present invention can serve as both positive and negative electrodes and can be used in the preparation of symmetrical batteries, among other applications. Symmetrical batteries, due to their unique assembly method, simplify the preparation process of positive and negative electrode materials while solving problems such as capacity decay caused by mismatches in the physical properties of the positive and negative electrode materials, thereby achieving a synergistic improvement in cycle stability and rate performance.

[0060] In a fourth aspect, the present invention provides a pole piece, wherein the active material of the pole piece includes the battery material.

[0061] In some optional embodiments, the electrode sheet includes a positive electrode sheet and a negative electrode sheet.

[0062] In some optional embodiments, the pole piece includes a current collector and a slurry layer coated on the surface of the current collector;

[0063] The current collector includes aluminum foil;

[0064] The slurry layer is mainly composed of the battery material of the present invention, a conductive agent and a binder.

[0065] In a fifth aspect, the present invention provides a symmetrical battery, wherein the positive electrode plate and the negative electrode plate of the symmetrical battery are both the aforementioned plates.

[0066] The battery has high specific capacity and long cycle life.

[0067] The present invention is further described below by means of specific examples and comparative examples. However, it should be understood that these examples are merely provided for more detailed description and are not to be construed as limiting the present invention in any form.

[0068] Example 1

[0069] A battery material comprising Na 2.5 Mn 0.5 V 0.5 Ti(PO4)3 material and carbon coated on its surface, wherein the carbon accounts for 12% by weight of the battery material. The preparation method is as follows:

[0070] Solution A: Use a complexing agent as a carbon source and stir evenly in an appropriate amount of deionized water (40-60 mL of deionized water is used for every 1 mol of positive electrode material synthesized). Then, add the vanadium source, manganese source, sodium source, and phosphorus source to the complexing agent solution in a stoichiometric ratio and stir for 1 hour to allow the complexing reaction to proceed fully.

[0071] Solution B: Add the titanium source to isopropanol according to the stoichiometric ratio and stir evenly for 30 minutes. Use 15-25 mL of isopropanol for every 1 mol of positive electrode material synthesized.

[0072] Solution B was added dropwise to solution A and stirred in a hot water bath at 80°C until a gel was formed. After grinding evenly, the mixture was dried at 110°C in a forced air drying oven for 8 h. After grinding, the mixture was sintered at 750°C in a tube furnace under N2 for 8 h at a heating rate of 5°C min -1 , get Na 2.5 Mn 0.5 V 0.5 Ti(PO4)3 / C.

[0073] The complexing agent is citric acid; the vanadium source is vanadium pentoxide; the manganese source is manganese acetate; the sodium source is sodium acetate; the phosphorus source is phosphoric acid; and the titanium source is tetraisopropyl titanate.

[0074] Example 2

[0075] A battery material comprising Na3Mn 0.1 V 1.8 Ti 0.1 (PO4)3 material and carbon coated on its surface, wherein the carbon mass accounts for 8% of the battery material. The preparation method is as follows:

[0076] Solution A: Use a complexing agent as a carbon source and stir evenly in deionized water (40-60 mL of deionized water is used for every 1 mol of positive electrode material synthesized). Then, add the vanadium source, manganese source, sodium source, and phosphorus source to the complexing agent solution in a stoichiometric ratio and stir for 1 hour to allow for sufficient complexation reaction.

[0077] Solution B: Add the titanium source to isopropanol according to the stoichiometric ratio and stir evenly for 30 minutes. Use 15-25 mL of isopropanol for every 1 mol of positive electrode material synthesized.

[0078] Solution B was added dropwise to solution A and stirred in a 75°C hot water bath until a gel was formed. After grinding evenly, the mixture was dried at 110°C in a forced air drying oven for 8 h. After grinding, the mixture was sintered at 700°C in a tube furnace under N2 for 10 h at a heating rate of 5°C min -1 , get Na3Mn 0.1 V 1.8 Ti 0.1 (PO4)3 / C.

[0079] The complexing agent is citric acid; the vanadium source is ammonium metavanadate; the manganese source is manganese acetylacetonate; the sodium source is sodium nitrate; the phosphorus source is ammonium dihydrogen phosphate; and the titanium source is tetrabutyl titanate.

[0080] Example 3

[0081] A battery material comprising Na3.1 MnV 0.1 Ti 0.9 (PO4)3 material and carbon coated on its surface, wherein the carbon accounts for 16% of the battery material by weight. The preparation method is as follows:

[0082] Solution A: Use a complexing agent as a carbon source and stir evenly in deionized water (40-60 mL of deionized water is used for every 1 mol of positive electrode material synthesized). Then, add the vanadium source, manganese source, sodium source, and phosphorus source to the complexing agent solution in a stoichiometric ratio and stir for 1 hour to allow for sufficient complexation reaction.

[0083] Solution B: Add the titanium source to isopropanol according to the stoichiometric ratio and stir evenly for 30 minutes. Use 15-25 mL of isopropanol for every 1 mol of positive electrode material synthesized.

[0084] Solution B was added dropwise to solution A and stirred in a hot water bath at 85°C until a gel was formed. After grinding evenly, the mixture was dried at 110°C in a forced air drying oven for 8 hours. After grinding, the mixture was sintered at 800°C in a tube furnace under N2 for 6 hours at a heating rate of 5°C min -1 , get Na 3.1 MnV 0.1 Ti 0.9 (PO4)3 / C.

[0085] The complexing agent is citric acid; the vanadium source is ammonium metavanadate; the manganese source is manganese nitrate; the sodium source is sodium carbonate; the phosphorus source is ammonium dihydrogen phosphate; and the titanium source is dihydroxybis(ammonium lactate)titanium.

[0086] Comparative Example 1

[0087] A battery material, which differs from Example 1 in that Na 2.5 Mn 0.5 V 0.5 The Ti(PO4)3 material was replaced by Na4MnV(PO4)3.

[0088] Comparative Example 2

[0089] A battery material, which differs from Example 1 in that Na 2.5 Mn 0.5 V 0.5 The Ti(PO4)3 material was replaced by Na3MnTi(PO4)3.

[0090] Comparative Example 3

[0091] A battery material, which differs from Example 1 in that the amount of carbon source is reduced so that Na 2.5 Mn 0.5 V 0.5 The surface of Ti(PO4)3 material is only coated with 5% carbon.

[0092] Test Example 1

[0093] The battery materials provided in Examples 1-3 were subjected to XRD pattern detection. The detection results of Example 1 are as follows: Figure 1 It was found that the XRD patterns of the materials provided in Examples 1-3 had fewer impurity peaks compared with the standard diffraction cards, indicating that they were pure phases.

[0094] Test Example 2

[0095] The battery materials provided in the above examples and comparative examples were mixed with the conductive agent SP and the binder PVDF in a weight ratio of 8:1:1, respectively, to form a slurry, which was then evenly coated on the surface of aluminum foil to prepare a pole piece. The prepared pole piece was then used as the positive pole piece, and a commercial sodium sheet was used as the negative pole piece. A 1M NaClO4 / PC electrolyte was used. A CR2032 half-cell was assembled in the following order: negative electrode shell, negative electrode sheet, separator (PP separator), electrolyte, positive electrode sheet, gasket, spring, and positive electrode shell. The battery was then cycled (voltage range 1.5-4.3V, using a 3C constant current step for charge and discharge). The results are as follows:

[0096] For the half-cell prepared from the battery material of Example 1, the charge and discharge curves show that the Na 2.5 Mn 0.5 V 0.5 The half-cell assembled by Ti(PO4)3 / C material can successfully stimulate V in the electrochemical window of 1.5-4.3V. 3+ / 4+ / 5+ 、Mn 2+ / 3+ , Ti 4+ / 3+ 、V 3+ / 2+ Electric pair (see Figure 2 ). It is confirmed that the three transition metals Mn, V, and Ti in the material are electrochemically active in the positive and negative electrode voltage ranges, respectively, and can be further matched to assemble symmetrical batteries. In addition, after testing, the half-cell assembled with the materials of Example 2-3 can also successfully stimulate V in the electrochemical window of 1.5-4.3V. 3+ / 4+ / 5+ 、Mn 2+ / 3+ , Ti 4+ / 3+ 、V 3+ / 2+ Electric pair.

[0097] Test Example 3

[0098] The battery materials provided in the above examples and comparative examples were mixed with the conductive agent SP and the binder PVDF in a weight ratio of 8:1:1, respectively, to form a slurry, which was then evenly coated on the surface of aluminum foil to prepare electrodes. The prepared electrodes were then used as positive and negative electrodes, and a 1M NaClO4 / PC electrolyte was used. CR2032 batteries were assembled in the following order: negative electrode shell, negative electrode sheet, separator (PP separator), electrolyte, positive electrode sheet, gasket, spring, and positive electrode shell. The batteries were then cycled (voltage range 1.0-3.0V, using a 3C constant current step for charge and discharge). The results are as follows:

[0099] Table 1

[0100]

[0101] For the symmetrical battery prepared from the battery material of Example 1, the symmetrical battery overcomes the mismatch of the physical properties of the materials, and the capacity retention rate can still reach 87.3% after 1000 cycles at 3C (see Figure 3 ), achieving a synergistic improvement in cycle stability and rate performance.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery material, characterized in that: The battery material includes Na 2.5 Mn 0.5 V 0.5 Ti(PO4)3 materials and carbon; The carbon is coated on Na 2.5 Mn 0.5 V 0.5 The surface of Ti(PO4)3 material; The mass proportion of carbon in the battery material is 8%-16%; The preparation method of the battery material comprises the following steps: using a complexing agent as a carbon source, mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source and a titanium source to form a gel, and then drying and sintering it in a protective atmosphere to prepare the battery material; The step of using a complexing agent as a carbon source and mixing it with a vanadium source, a manganese source, a sodium source, a phosphorus source and a titanium source to form a gel comprises: a. mixing a complexing agent, a vanadium source, a manganese source, a sodium source and a phosphorus source, and performing a complexation reaction; b. The solution containing the titanium source is added dropwise to the solution after the complexation reaction in step a, and a gel is formed after heating in a water bath.

2. The battery material according to claim 1, characterized in that The water bath heating temperature is 75-85°C.

3. The battery material according to claim 1, characterized in that The complexing agent includes citric acid; The vanadium source includes at least one of vanadium pentoxide or ammonium metavanadate; The manganese source includes at least one of manganese acetate, manganese nitrate or manganese acetylacetonate; The sodium source includes at least one of sodium acetate, sodium carbonate, sodium nitrate, sodium dihydrogen phosphate or sodium hydroxide; The phosphorus source includes at least one of phosphoric acid or ammonium dihydrogen phosphate; The titanium source includes at least one of tetraisopropyl titanate, tetrabutyl titanate or dihydroxybis(ammonium lactate) titanium.

4. The battery material according to claim 1, characterized in that The sintering temperature is 700-800°C; The sintering time is 6-10 h.

5. Use of the battery material according to claim 1 in a battery.

6. A pole piece, characterized in that: The active material of the electrode sheet includes the battery material according to claim 1.

7. A symmetrical battery, characterized in that: The positive electrode sheet and the negative electrode sheet of the symmetrical battery are both the electrode sheets according to claim 6.

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