Preparation method of positive electrode substrate modified material and zinc-manganese battery
By generating nano-chromium oxide or nano-chromium nitride on carbon cloth to form a three-dimensional conductive network, the problems of insufficient conductivity and ion diffusion in zinc-manganese batteries are solved, and the high-efficiency cycle performance and high-current charge-discharge capability of zinc-manganese batteries are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-27
AI Technical Summary
In zinc-manganese batteries, the manganese oxide deposited on pure carbon cloth has poor electronic conductivity and insufficient ion diffusion pathways, resulting in poor rate performance of the battery.
By immersing carbon cloth in a chromium salt solution and then heating it in an air or ammonia atmosphere using Joule heating technology, nano-chromium oxide or nano-chromium nitride is generated, forming a three-dimensional conductive network, which improves the conductivity of the carbon cloth and increases the number of active sites.
It significantly improves the conductivity and active sites of carbon cloth, enhances the cycle performance and rate performance of zinc-manganese batteries, and significantly improves cycle stability and high-current charge-discharge capability.
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Figure CN121748341A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of battery materials, in particular to a preparation method of a positive electrode substrate modified material and a zinc-manganese battery. BACKGROUND
[0002] With the substantial development of human industry, the consumption of fossil energy is rapidly increasing, the emission of greenhouse gases is increasing, and the ecology of the entire earth is greatly affected. In order to solve this problem, finding clean renewable energy and storing and utilizing it are the primary tasks of the entire energy industry at present.
[0003] The use of batteries to store chemical energy converted from electrical energy provides a solution for the possibility of replacing fossil energy with clean energy such as solar energy and wind energy. Among them, manganese-based batteries gradually attract people's interest because of their low cost, high safety, high energy density and long cycle life.
[0004] In the zinc-manganese battery, the manganese oxide deposited on the pure carbon cloth has poor intrinsic electronic conductivity and insufficient ion diffusion path, so that the rate performance of the battery is poor. SUMMARY
[0005] The application provides a preparation method of a positive electrode substrate modified material and a zinc-manganese battery, and the preparation method improves the conductivity of the carbon cloth and increases the active sites of the carbon cloth.
[0006] The application provides a preparation method of a positive electrode material, which comprises the following steps: The carbon cloth is immersed in a chromium salt solution and then dried to obtain a carbon cloth loaded with chromium salt; The carbon cloth loaded with chromium salt is heated in an air or ammonia atmosphere by using a Joule heat technology to generate nano-chromium oxide or nano-chromium nitride, so as to obtain the positive electrode material; The heating temperature is 850-950 DEG C. The chromium salt comprises chromium chloride.
[0007] Preferably, the mass fraction of the chromium salt in the chromium salt solution is 8-20%.
[0008] Preferably, the thickness of the carbon cloth is 0.32+ / -0.02 mm, the longitudinal resistance is 0.0013 omega, the transverse resistance is 0.5 omega, and the grammage is 110-150 g / m 2 .
[0009] Preferably, before the immersion, the method further comprises: pretreating the carbon cloth.
[0010] Preferably, the pretreatment comprises: immersing the carbon cloth in an ethanol aqueous solution, then taking out the carbon cloth after ultrasonic treatment and drying, and then heating the dried carbon cloth by using a Joule heat technology. The heating treatment temperature is 750-800 DEG C, and the time is 3s.
[0011] Preferably, the impregnation time is 3-5 min.
[0012] Preferably, the drying temperature is 50-60 DEG C, and the time is 10-12h.
[0013] Preferably, the heating time is 6-8s.
[0014] The application also provides a zinc-manganese battery, wherein the positive electrode material of the zinc-manganese battery is the positive electrode material prepared by the preparation method.
[0015] Preferably, the electrolyte of the zinc-manganese battery comprises zinc acetate, manganese acetate and water.
[0016] The positive electrode material prepared by adjusting the type of chromium salt, heating atmosphere and temperature improves the conductivity of carbon cloth and increases the active sites of carbon cloth: the conductivity: the chromium oxide nanoparticles form a three-dimensional conductive network with carbon cloth, reducing the interface resistance; the active sites are increased: the morphology of the nanometer spherical particles of chromium oxide in Cr2O3@CC greatly increases the active sites, improving the cycle performance under high surface capacity.
[0017] The preparation method is simple in process, uniform in loading and high in yield. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 It is a scanning electron microscope graph of the Cr2O3@CC composite substrate in Example 1. Figure 2 It is an energy spectrum analysis of the Cr2O3@CC composite substrate in Example 1. Figure 3 It is an XRD of carbon cloth and the Cr2O3@CC composite substrate in Example 1. Figure 4 It is a Raman spectrum of the Cr2O3@CC composite substrate in Example 1. Figure 5 It is a BET of carbon cloth and the Cr2O3@CC composite substrate in Example 1. Figure 6 It is the small surface capacity cycle performance result of the Zn / / Cr2O3@CC battery. Figure 7 It is the charge-discharge curve of the Zn / / Cr2O3@CC battery. Figure 8 It is the rate performance result of the Zn / / Cr2O3@CC battery. Figure 9 It is the large surface capacity cycle performance result of the Zn / / Cr2O3@CC battery. Figure 10 Results of small area capacity cycle performance of Zn / / CC batteries; Figure 11 The charge / discharge curves of the Zn / / CC battery; Figure 12 Results of large-area capacity cycle performance of Zn / / CC batteries; Figure 13 The results of cycle tests on the composite substrates of Example 1 and Comparative Example 1 assembled into coin cells; Figure 14 The test results are for the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 2. Figure 15 The test results are for the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 3. Figure 16 The test results are for the batteries assembled on the composite substrates obtained in Examples 1 and 2; Figure 17 The results are the test results of the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 4. Detailed Implementation
[0019] This invention provides a method for preparing a cathode material, comprising the following steps: Carbon cloth is immersed in a chromium salt solution and then dried to obtain chromium salt-loaded carbon cloth; In an air or ammonia atmosphere, the carbon cloth loaded with chromium salts is heated using Joule heating technology to generate nano-chromium oxide or nano-chromium nitride, thereby obtaining the cathode material. The heating temperature is 850~950℃; The chromium salt includes chromium chloride.
[0020] The present invention involves immersing carbon cloth in a chromium salt solution and then drying it to obtain carbon cloth loaded with chromium salt.
[0021] Before impregnation, the present invention preferably further includes: pre-treating the carbon cloth.
[0022] In this invention, the pretreatment preferably includes: immersing the carbon cloth in an aqueous solution of ethanol, ultrasonicating it, removing it and drying it, and then heating the dried carbon cloth using Joule heating technology. The heat treatment is performed at a temperature of 750~800℃ for 3 seconds.
[0023] In this invention, the volume ratio of ethanol to water in the aqueous solution of ethanol is preferably 1:1.
[0024] In this invention, the thickness of the carbon cloth is preferably 0.32±0.02 mm, the longitudinal resistance is preferably 0.0013 Ω, the transverse resistance is preferably 0.5 Ω, and the basis weight is preferably 110~150 g / m². 2 .
[0025] In this invention, the mass fraction of chromium salt in the chromium salt solution is preferably 8-20%, and in specific embodiments of this invention it can be 10%, 12%, 15%, 17% or 18%; the chromium salt in the chromium salt solution includes chromium chloride.
[0026] In this invention, the soaking time is preferably 3 to 5 minutes.
[0027] In this invention, the drying temperature is preferably 50~60℃, and the drying time is preferably 10~12h.
[0028] After obtaining the carbon cloth loaded with chromium salts, the present invention heats the carbon cloth loaded with chromium salts in an air or ammonia atmosphere using Joule heating technology to generate nano-chromium oxide or nano-chromium nitride, thereby obtaining the cathode material.
[0029] In this invention, the heating temperature is preferably 850~950℃, and in specific embodiments of this invention, it can be 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃ or 940℃. The heating time is preferably 6~8s.
[0030] After heating, the present invention preferably also cools down.
[0031] The present invention also provides a zinc-manganese battery, wherein the positive electrode material of the zinc-manganese battery is the positive electrode material prepared by the preparation method described in the above technical solution.
[0032] In this invention, the electrolyte of the zinc-manganese battery preferably comprises zinc acetate, manganese acetate, and water. The following detailed description, in conjunction with embodiments, illustrates the material preparation method for positive electrode substrate modification and the zinc-manganese battery provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.
[0033] Example 1 Weigh 3.9978 g of chromium chloride hexahydrate and place it in a beaker containing 20 mL of water. Stir for 15 min to obtain solution a.
[0034] Will Thickness: 0.32±0.02mm; Longitudinal resistivity: 0.0013Ω; Transverse resistivity: 0.5Ω; Weight: 110~150g / m³ 2The carbon cloth was immersed in a mixed solution of ethanol:water = 1:1 (volume ratio) and sonicated for 30 min, dried in an oven at 50°C for 7 h, and then subjected to Joule heating at 800°C for 3 s to obtain pretreated carbon cloth.
[0035] The pretreated carbon cloth was immersed in solution a for 3 minutes, and then dried in a vacuum oven at 60°C for 12 hours. The dried carbon cloth was then clamped in a graphite fixture and placed in a Joule heating device. It was treated at 900°C in air for 8 seconds, during which chromium chloride decomposed into chromium hydroxide and hydrogen chloride gas. Chromium hydroxide decomposed into chromium oxide under heating conditions. Finally, the mixture was rapidly cooled to room temperature in air, and the resulting Cr2O3@CC composite substrate was removed for further testing and characterization.
[0036] Figure 1 This is a scanning electron microscope image of the Cr2O3@CC composite substrate in Example 1; Figure 2 Energy dispersive spectroscopy analysis of the Cr2O3@CC composite substrate in Example 1; pass Figure 2 The mapping of Cr, O, and C elements shows that chromium oxide is evenly distributed on the carbon cloth.
[0037] Figure 3 The image shows the XRD pattern of the carbon cloth and Cr2O3@CC composite substrate in Example 1.
[0038] Depend on Figure 3 It can be seen that the standard cards for Cr2O3@CC composite substrate and chromium oxide material are basically consistent, and its morphology on the carbon cloth surface is nanosphere particles.
[0039] Figure 4 The image shows the Raman spectrum of the Cr2O3@CC composite substrate in Example 1.
[0040] Figure 4 The Raman spectroscopy also confirmed that the metal oxide on the composite substrate was chromium oxide.
[0041] Figure 5 The BET is the carbon cloth and Cr2O3@CC composite substrate in Example 1.
[0042] Figure 5 This indicates that the Cr2O3@CC composite substrate has a larger specific surface area compared to the pure CC substrate.
[0043] Characterization tests on the unmodified substrate further demonstrated that the substrate modified with metal oxides exhibited superior performance. Furthermore, the modified substrate showed higher coulombic efficiency, and no significant color change in the solution before and after cycling, indicating that the Cr2O3@CC composite substrate can guide uniform deposition and reduce the formation of dead manganese.
[0044] H-cell batteries are assembled using a Cr2O3@CC composite substrate or carbon cloth (CC) as the positive electrode, Zn foil as the negative electrode, and N117 as the separator. The positive electrode electrolyte is 0.5M manganese acetate + 1M sodium chloride + water, and the negative electrode electrolyte is 0.5M zinc acetate + 1M sodium chloride + water. Batteries prepared on the Cr2O3@CC composite substrate are denoted as Zn / / Cr2O3@CC batteries, and batteries prepared on the CC substrate are denoted as Zn / / CC batteries.
[0045] The test was conducted using constant-capacity charge-discharge, charging to 1mAh cm⁻¹. -2 At 5mA cm -2 Discharge was performed, and cycle performance testing was conducted at 0.8V for charge-discharge testing. The results are as follows: Figure 6~7 , Figure 10~11 As stated above.
[0046] Figure 6 Results of small-area capacity cycle performance of Zn / / Cr2O3@CC batteries.
[0047] Figure 7 The charge-discharge curves of the Zn / / Cr2O3@CC battery are shown.
[0048] Figure 10 The results show the small-area capacity cycle performance of Zn / / CC batteries.
[0049] Figure 11 The charge / discharge curves of the Zn / / CC battery are shown.
[0050] The Zn / / Cr2O3@CC and Zn / / CC batteries were tested using constant-capacity charge-discharge, and charged to 1 mAh cm⁻¹. -2 At 1, 2, 4, 6, 8, and 10 mA cm, respectively -2 Discharge under current, rate test at 0.8V, results are as follows. Figure 8 As shown.
[0051] Figure 8 The results show the rate performance of the Cr2O3@CC composite substrate. The Zn / / Cr2O3@CC and Zn / / CC batteries were tested using constant-capacity charge-discharge, and charged to 10 mAh cm⁻¹. -2 , at 5mA cm -2 Discharge was performed, and cycle performance testing was conducted at 0.8V. The results are as follows: Figure 9 and Figure 12 As shown.
[0052] Figure 9 Results of large-area capacity cycle performance of Zn / / Cr2O3@CC batteries.
[0053] Figure 12 The results show the large-area capacity cycle performance of Zn / / CC batteries.
[0054] Depend on Figure 6 and 10 It can be seen that the electrochemical performance of the Zn / / Cr2O3@CC battery is within 1 mAh cm⁻¹. -2 It exhibits remarkable cycle stability at its areal capacity, exceeding 2500 cycles, and its coulombic efficiency (98.63%) significantly surpasses that of Zn / / CC batteries.
[0055] Depend on Figure 9 and 12 It can be seen that even under higher areal capacity conditions (10 mAh cm⁻¹), -2 The Zn / / Cr2O3@CC battery also maintains excellent cycle stability, with more than 250 cycles, which is in stark contrast to the Zn / / CC battery that only achieved 64 cycles.
[0056] Although both cells exhibited similar plateau potentials in the initial cycle, the potential of the cell with a pure CC electrode continued to increase. Figure 7 and Figure 11 ).
[0057] Figure 8 This indicates that the Zn / / Cr2O3@CC battery exhibits superior rate performance, with the capacity loss remaining almost constant as the areal current density increases. Even at 10 mA cm⁻¹ -2 At high surface currents, the capacity retention rate reached 81.6%. This indicates that Cr2O3@CC induced the deposition of oxygen-vacancy-rich MnO2, thereby enhancing the capacity retention of MnO2. 2+ -MnO2 electrochemical reaction kinetics.
[0058] The Cr2O3@CC composite substrate prepared in this invention has superior cycle stability, rate performance, and high-current charge / discharge capability compared to the original CC substrate.
[0059] Compared to unmodified pure carbon cloth, this method solves the problems of sediment aggregation, poor cycle stability, and low coulombic efficiency during the deposition process. A comparison can be seen... Figure 10 Pure carbon cloth exhibits poor cycling stability, with capacity retention approaching zero after less than 1000 cycles. Furthermore, the charge-discharge curves reveal significant polarization in pure carbon cloth. Figure 12 Medium-purity carbon cloth only cycles 70 times under large capacity conditions. The short cycle life may be related to its poor conductivity and slow zinc ion transport kinetics.
[0060] Comparative Example 1 The only difference from Example 1 is that chromium chloride hexahydrate is replaced with cobalt nitrate hexahydrate (cobalt nitrate hexahydrate and chromium chloride hexahydrate have the same amount of substance), resulting in an ACC@Co3O4 composite substrate.
[0061] The composite substrates of Example 1 and Comparative Example 1 were assembled into coin cells and then subjected to cycle tests. The electrolyte in the coin cells was 0.5M manganese acetate + 0.5M zinc acetate + water, the negative electrode was 1mm zinc foil, and the separator was a glass fiber separator.
[0062] During the cyclic test, the charging speed was 0.5 mA / cm. -2 Charged to 0.5mAh cm -2 Discharge: 0.5mA cm -2 Discharge to 0.8V.
[0063] Figure 13 The results show the cycle test results of the composite substrates of Example 1 and Comparative Example 1 assembled into coin cells.
[0064] Depend on Figure 13 It can be seen that, compared with the modification of Co3O4 oxide, the composite substrate modified with Cr2O3 can cycle stably in the zinc-manganese system, and its cycle life is almost three times that of Co3O4.
[0065] Comparative Example 2 The only difference from Example 1 is that chromium chloride hexahydrate is replaced with nickel chloride, copper chloride, cobalt chloride, or ferric chloride in the same amount of substance as chromium chloride hexahydrate.
[0066] Figure 14 The results are the test results of the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 2.
[0067] Assembled as a button cell: the electrolyte is 0.5M manganese acetate + 0.5M zinc acetate + water, the negative electrode is 1mm zinc foil, and the separator is a glass fiber separator.
[0068] The test conditions were: constant current and constant capacity charging to 0.5 mAh cm⁻¹ -2 It discharges under constant current to 0.8V.
[0069] Depend on Figure 14 It can be seen that chromium salts have the best performance as metal precursors, with a cycle life of up to 100 cycles, while nickel salts have 44 cycles, copper salts have 38 cycles, iron salts have 42 cycles, and cobalt salts have only about 20 cycles.
[0070] Comparative Example 3 The only difference from Example 1 is that chromium chloride hexahydrate is replaced with Cr(NO3)3 or Cr2(SO4)3 of the same amount as chromium chloride hexahydrate.
[0071] Figure 15The results are the test results of the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 3.
[0072] Assembled into a button cell: the positive electrode electrolyte is 0.5M manganese acetate + 0.5M zinc acetate + water, the negative electrode is 1mm zinc foil, and the separator is a glass fiber separator.
[0073] The test conditions were: constant current and constant capacity charging to 0.5 mAh cm⁻¹ -2 It discharges under constant current to 0.8V.
[0074] from Figure 15 It can be seen that CrCl3 has the best performance as a metal precursor, with a cycle life of up to 100 cycles, while Cr(NO3)3 has only 15 cycles and Cr2(SO4)3 has only 25 cycles.
[0075] Example 2 The only difference from Example 1 is that the process is carried out in ammonia using Joule heating technology.
[0076] Figure 16 The results are the test results of the batteries assembled on the composite substrates obtained in Examples 1 and 2.
[0077] Assembled into a button cell: the positive electrode electrolyte is 0.5M manganese acetate + 0.5M zinc acetate + water, the negative electrode is 1mm zinc foil, and the separator is a glass fiber separator.
[0078] The test conditions were: constant current and constant capacity charging to 0.5 mAh cm⁻¹ -2 It discharges under constant current to 0.8V.
[0079] Depend on Figure 16 It can be seen that air is the best reaction atmosphere, with a cycle life of up to 100 cycles. However, when ammonia is used as the reaction atmosphere, the cycle life can reach 78 cycles. Therefore, air is determined to be the best reaction atmosphere.
[0080] Chromium oxide may exhibit good stability in common electrolyte environments and other systems, maintaining relative structural and chemical stability during manganese deposition and dissolution, thus providing a suitable environment for manganese reactions. In contrast, chromium nitride may exhibit poor stability under the same chemical conditions, readily undergoing side reactions with other components in the system, or its own structure may change during manganese deposition and dissolution, thereby affecting manganese deposition and dissolution performance.
[0081] Comparative Example 4 The only difference from Example 1 is that the heating temperature is 800°C or 1000°C.
[0082] Figure 17 The results are the test results of the batteries assembled on the composite substrates obtained in Example 1 and Comparative Example 4.
[0083] Assembled into a button cell: the positive electrode electrolyte is 0.5M manganese acetate + 0.5M zinc acetate + water, the negative electrode is 1mm zinc foil, and the separator is a glass fiber separator.
[0084] The test conditions were: constant current and constant capacity charging to 0.5 mAh cm⁻¹ -2 It discharges under constant current to 0.8V.
[0085] from Figure 17 It can be seen that the optimal reaction temperature is 900℃, with a cycle life of up to 100 cycles. However, if the reaction temperature is 800℃, the cycle efficiency is low and the cycle life is short. Worse still, calcination at 1000℃ results in almost no capacity.
[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a positive electrode material, characterized in that, Includes the following steps: Carbon cloth is immersed in a chromium salt solution and then dried to obtain chromium salt-loaded carbon cloth; In an air or ammonia atmosphere, the carbon cloth loaded with chromium salts is heated using Joule heating technology to generate nano-chromium oxide or nano-chromium nitride, thereby obtaining the cathode material. The heating temperature is 850~950℃; The chromium salt includes chromium chloride.
2. The preparation method according to claim 1 or 2, characterized in that, The mass fraction of chromium salt in the chromium salt solution is 8-20%.
3. The preparation method according to claim 1, characterized in that, The carbon cloth has a thickness of 0.32±0.02mm, a longitudinal resistivity of 0.0013Ω, a transverse resistivity of 0.5Ω, and a basis weight of 110~150g / m². 2 .
4. The preparation method according to claim 1 or 3, characterized in that, Before impregnation, the process also includes pre-treating the carbon cloth.
5. The preparation method according to claim 4, characterized in that, The pretreatment includes: immersing the carbon cloth in an aqueous ethanol solution, ultrasonicating it, removing it and drying it, and then heating the dried carbon cloth using Joule heating technology. The heat treatment is performed at a temperature of 750~800℃ for 3 seconds.
6. The preparation method according to claim 1, characterized in that, The soaking time is 3-5 minutes.
7. The preparation method according to claim 1, characterized in that, The drying temperature is 50~60℃, and the time is 10~12h.
8. The preparation method according to claim 1, characterized in that, The heating time is 6-8 seconds.
9. A zinc-manganese battery, characterized in that, The positive electrode material of the zinc-manganese battery is the positive electrode material prepared by the preparation method according to any one of claims 1 to 9.
10. The zinc-manganese battery according to claim 9, characterized in that, The electrolyte of the zinc-manganese battery includes zinc acetate, manganese acetate, and water.