A Ti 4+ Doped ZnMn2O4, method for its preparation and use as positive electrode material for zinc-ion batteries
By doping Ti4+ ions into ZnMn2O4, the problems of electronic conductivity and slow ion diffusion were solved, improving the specific capacity and cycle performance of zinc-ion batteries, and achieving improvements in structural stability and electrochemical reaction kinetics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LANZHOU PETROCHEMICAL VOCATIONAL & TECH UNIV
- Filing Date
- 2026-04-01
- Publication Date
- 2026-07-21
AI Technical Summary
ZnMn2O4, as a cathode material for zinc-ion batteries, suffers from low electronic conductivity, slow ion diffusion kinetics, and rapid capacity decay during long-term cycling, which limits its application.
Ti4+ ions were doped into the ZnMn2O4 lattice, especially at the Mn sites. Ti4+-doped ZnMn2O4 was prepared by calcining a mixture of zinc, manganese and titanium sources, which maintained the spinel structure while improving charge transport performance and cycle stability.
The specific capacity and cycle performance of ZnMn2O4 material in aqueous zinc-ion batteries were improved, the structural stability was enhanced, the electrode polarization was reduced, and the co-transport of electrons and Zn2+ was promoted, thereby improving the electrochemical reaction kinetics.
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Figure CN122436483A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of zinc-ion battery cathode materials, specifically relating to a Ti... 4+ Doped ZnMn2O4. Background Technology
[0002] Aqueous zinc-ion batteries have shown promising application prospects in large-scale energy storage and flexible electronic devices due to their advantages such as high safety, low cost, and environmental friendliness. Among them, the cathode material, as one of the key factors affecting the energy density and cycle life of zinc-ion batteries, has attracted widespread attention for performance optimization.
[0003] ZnMn2O4 is considered a promising cathode material for zinc-ion batteries due to its high theoretical capacity, abundant redox active sites, and good structural stability. However, in actual charge-discharge processes, ZnMn2O4 still suffers from low electronic conductivity, slow ion diffusion kinetics, and rapid capacity decay during long cycles, which limits its further application. Summary of the Invention
[0004] To address the shortcomings of ZnMn2O4 as a cathode material for zinc-ion batteries, this invention provides a Ti... 4+ Doping with ZnMn2O4 improves charge transport performance and cycle stability.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A Ti 4+ The doped ZnMn2O4 is characterized in that: the Ti 4+ The Ti replaces the Mn sites in the ZnMn2O4 lattice. 4 + The molar doping amount is 0.3~3%.
[0007] Preferably, the Ti 4+ The molar doping amount is 0.9~2.1%.
[0008] The above Ti 4+ The preparation method of doped ZnMn2O4 includes: ball milling and mixing zinc source, manganese source and titanium source, followed by calcination to obtain the Ti. 4+ Doped ZnMn2O4.
[0009] Preferably, the zinc source is zinc nitrate, zinc acetate, or zinc oxide.
[0010] Preferably, the manganese source is manganese nitrate, manganese acetate, manganese carbonate, or manganese oxide.
[0011] Preferably, the titanium source is titanium dioxide.
[0012] Preferably, the calcination temperature is 600°C and the time is 3 hours.
[0013] More preferably, the heating rate of the calcination is 2 °C / min.
[0014] The above Ti 4+ Applications of doped ZnMn2O4 as a cathode material for zinc-ion batteries.
[0015] This invention, without altering the main crystal structure of ZnMn2O4 spinel, incorporates high-valence Ti ions... 4+ Mn sites doped in ZnMn2O4, electrochemically inert Ti 4+ Doping at Mn sites can stabilize the Mn-O bond framework in the ZnMn2O4 spinel structure, thereby improving the structural stability of ZnMn2O4 during repeated charge-discharge processes; due to Ti 4+ With a high valence state, it can act as a charge center to promote charge transfer, enabling ZnMn2O4 materials to maintain high specific capacity and good cycle performance in aqueous zinc-ion batteries. Attached Figure Description
[0016] Figure 1 The X-ray photoelectron spectrum of the titanium-doped ZnMn2O4 cathode material in Example 6 is shown.
[0017] Figure 2 The X-ray diffraction pattern of the titanium-doped ZnMn2O4 cathode material in Example 6 is shown.
[0018] Figure 3 The X-ray diffraction pattern of the titanium-doped ZnMn2O4 cathode material in Example 6 is a refined image.
[0019] Figure 4 The graphs show the rate performance of coin cells using titanium-doped ZnMn2O4 as the cathode material in Examples 1-7 at different current densities.
[0020] Figure 5 The cyclic voltammetry curves of coin cells using undoped ZnMn2O4 and titanium-doped ZnMn2O4 from Example 6 as cathode materials are shown at the same scan rate.
[0021] Figure 6 Electrochemical impedance spectroscopy (EIS) diagrams are shown for coin cells using undoped ZnMn2O4 and titanium-doped ZnMn2O4 from Example 6 as cathode materials, respectively.
[0022] Figure 7 The graphs show the rate performance of coin cells using undoped ZnMn2O4 and titanium-doped ZnMn2O4 from Example 6 as cathode materials at different current densities.
[0023] Figure 8 To test the coin cell using titanium-doped ZnMn2O4 as the positive electrode material in Example 6 at 0.1 A·g - Charge-discharge cycle curves at current density ¹.
[0024] Figure 9 To test the coin cell using titanium-doped ZnMn2O4 as the positive electrode material in Example 6 at 1.0 A·g - Charge-discharge cycle curves at current density ¹. Detailed Implementation
[0025] The technical solution of the present invention will be further described in detail below with reference to the embodiments.
[0026] Example 1
[0027] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed separately according to a molar ratio of Zn:Mn:Ti = 3:6:0.009. The raw materials were transferred to a ball mill jar and mixed by dry ball milling at a speed of 400 r / min for 4 h.
[0028] After ball milling, the resulting mixture was placed in an oven and dried at 60 °C for 12 h. The dried powder was then transferred to a tube furnace and heated from room temperature to 600 °C at a rate of 2 °C / min in air, and held at that temperature for 3 h. After naturally cooling to room temperature, Ti was obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 0.3% (denoted as T) 0.3 ZMO).
[0029] Example 2
[0030] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.018. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 0.6% (denoted as T) 0.6 ZMO).
[0031] Example 3
[0032] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.027. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 0.9% (denoted as T) 0.9 ZMO).
[0033] Example 4
[0034] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.036. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 1.2% (denoted as T) 1.2 ZMO).
[0035] Example 5
[0036] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.045. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 1.5% (denoted as T) 1.5 ZMO).
[0037] Example 6
[0038] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.054. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 1.8% (denoted as T) 1.8 ZMO).
[0039] Example 7
[0040] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and TiO2 were weighed according to a molar ratio of Zn:Mn:Ti = 3:6:0.063. The remaining preparation steps were the same as in Example 1, and TiO2 was finally obtained. 4+ ZnMn2O4 cathode material with a molar doping content of 2.1% (denoted as T) 2.1 ZMO).
[0041] Figure 1 The X-ray photoelectron spectroscopy (XPS) full spectrum of the titanium-doped ZnMn2O4 cathode material (Ti-ZMO) in Example 6 shows that Ti 4+ The doped sample exhibits a Ti 2p characteristic peak at a binding energy of approximately 460 eV, while the ZnMn2O4 sample (ZMO) does not have this characteristic peak. The Zn 2p, Mn 2p, and O 1s characteristic peaks appear at binding energies of approximately 1020 eV, 640 eV, and 530 eV, respectively, proving that Ti was successfully doped while Zn, Mn, and O elements maintained their original chemical environments.
[0042] Figure 2 The X-ray diffraction pattern of the titanium-doped ZnMn2O4 cathode material in Example 6 is shown. By comparing it with the standard card PDF#71-2499 in the figure, it can be seen that all the diffraction peaks correspond to the diffraction peaks of zinc manganese oxide (ZnMn2O4). The characteristic diffraction peaks with 2θ in the range of 30°~40° have the highest intensity. No impurity peaks appear, indicating that the material after doping is still a pure phase spinel structure with good crystallinity, and the doping was successful.
[0043] Figure 3 The X-ray diffraction pattern of the titanium-doped ZnMn2O4 cathode material in Example 6 is shown. The results show that Ti is doped at the Mn site. The goodness of fit parameter Rwp = 11.7%, which is far below the good fit threshold of 15%. The (103) crystal plane diffraction peak is the strongest peak, which proves that the refinement result is reliable. The Ti occupancy is consistent with the experimental material ratio.
[0044] Electrochemical performance
[0045] The Ti prepared in Examples 1-7 4+ Doped ZnMn2O4 was used as the positive electrode active material, mixed with conductive agent acetylene black and binder PTFE in a mass ratio of 7:2:1, and ground into a slurry with anhydrous ethanol. This slurry was then coated onto a steel mesh and dried to form the positive electrode sheet. Zinc foil was used as the negative electrode, glass fiber as the separator, and the electrolyte (2 mol·L⁻¹) was applied. - ¹ ZnSO4 and 0.1 mol·L -¹ MnSO4) was used to assemble CR2032 coin cells. Charge-discharge tests were conducted at 20–25°C, with a voltage range of 1.8–3.6 V.
[0046] Figure 4 Ti with different doping concentrations 4+ Rate performance of ZnMn2O4 doped cathode material at different current densities. All tests were conducted at 0.1 A·g. - ¹、0.2 A·g - ¹、0.3 A·g - ¹、0.4 A·g - ¹ Four current densities were used for a total of 44 cycles to conduct a systematic comparative analysis. Experimental results show that the first 1-5 cycles represent the activation period of the zinc-ion battery, during which the electrode material exhibits low specific capacity and poor stability; with the increase of Ti... 4+ With the increase of doping amount, T x The highest specific capacities of the ZMO (x=0.3-2.1%) samples were 132 mAh·g, respectively. - ¹, 134 mAh·g - ¹, 157 mAh·g - ¹, 171 mAh·g - ¹, 176 mAh·g - ¹、217mAh·g - ¹, 179mAh·g - ¹. Among them, the sample of Example 6 (x=1.8%) showed a characteristic of first increasing and then stabilizing: the specific capacity rapidly increased to 217 mAh·g in the first 10 cycles. - ¹, then fluctuated slightly and stabilized at 180 mAh·g - ¹, Furthermore, under the conditions of this study, Ti 4+ The ZnMn2O4 cathode material with a molar doping content of 2.1% also exhibits relatively superior overall electrochemical performance.
[0047] Figure 5 The cyclic voltammograms of coin cells using undoped ZnMn2O4 and titanium-doped ZnMn2O4 (from Example 6) as cathode materials are shown at the same scan rate. Under the same scan rate conditions, both the titanium-doped ZnMn2O4 and undoped ZnMn2O4 samples exhibit paired redox peaks, indicating that their energy storage mechanism originates from ZnMn2O4. 2+ The reversible insertion / extraction process in spinel structures, while Ti 4+ The doped sample exhibits a higher peak current density and a smaller interpeak potential difference, indicating that Ti... 4+ The introduction of this effectively reduced electrode polarization, optimized lattice stability, and promoted electron interaction with Zn. 2+The synergistic transport of these components enhances the kinetics and reversibility of electrochemical reactions.
[0048] Figure 6 The following are electrochemical impedance spectroscopy (EIS) diagrams for coin cells using undoped ZnMn2O4 and titanium-doped ZnMn2O4 (from Example 6) as cathode materials. The Nyquist impedance spectra of each sample consist of a semicircle in the high-frequency region and a diagonal line in the low-frequency region, corresponding to the charge transfer impedance and Zn2O4 impedance, respectively. 2+ Diffusion behavior; compared to ZnMn2O4, the titanium-doped ZnMn2O4 sample exhibits a smaller high-frequency semicircle and a more vertical low-frequency sloping line, indicating that Ti... 4+ Doping effectively reduces interfacial charge transfer impedance and promotes Zn 2+ Diffusion improves electrochemical reaction kinetics.
[0049] Figure 7 This is a comparison of the rate performance of titanium-doped ZnMn2O4 and undoped ZnMn2O4 prepared in Example 6 at different current densities. The specific capacity of the titanium-doped ZnMn2O4 electrode is higher than that of the undoped ZnMn2O4 material throughout the entire rate range. At an initial current density of 0.1 A·g... - Under the specified conditions, the specific capacity of titanium-doped ZnMn2O4 is 217.01 mAh·g. - ¹, higher than the 126.13 mAh·g of undoped ZnMn2O4. - ¹. As the current density gradually increases to 0.2 A·g - ¹、0.3 A·g - ¹、0.4A·g - ¹、0.5 A·g - ¹、0.8 A·g - ¹、1 A·g - ¹、2 A·g - ¹、3 A·g - ¹ and 4 A·g - ¹, the specific capacity of titanium-doped ZnMn₂O₄ remained at 193.17 mAh·g⁻¹. - ¹, 166.56 mAh·g - ¹, 132.14 mAh·g - ¹, 106.16 mAh·g - ¹、94.40 mAh·g - ¹, 75.64 mAh·g - ¹、67.20 mAh·g - ¹、55.92 mAh·g - ¹ and 66.78 mAh·g -¹, both significantly higher than undoped ZnMn2O4 (112.64 mAh·g at the same rate). - ¹, 100.06 mAh·g - ¹、81.84 mAh·g - ¹, 64.38 mAh·g - ¹、58.37 mAh·g - ¹、50.52 mAh·g - ¹, 44.34 mAh·g - ¹, 38.77 mAh·g - ¹ and 44.17 mAh·g - ¹), the current density of titanium-doped ZnMn₂O₄ material returns to 0.1 A·g after high-current charge-discharge. - ¹At that time, it still has approximately 187.52 mAh·g - The discharge specific capacity of ¹ and the capacity recovery rate of approximately 86.41% indicate that this titanium-doped zinc-manganese oxide has excellent rate performance.
[0050] Figure 8 The titanium-doped ZnMn2O4 of Example 6 was prepared at 0.1 A·g - ¹Charge-discharge cycle test results: First discharge specific capacity 217.01 mAh·g - ¹, First charge specific capacity 215.51 mAh·g - ¹, the coulombic efficiency is approximately 100.70% (due to additional redox reactions at the positive electrode and side reactions in the electrolyte, the apparent discharge specific capacity exceeds the charge specific capacity); the discharge specific capacity after 50 cycles is 196.46 mAh·g. - ¹, Charging specific capacity 197.41 mAh·g - ¹, with a coulombic efficiency of approximately 99.46%; and a discharge specific capacity of 169.74 mAh·g after 100 cycles. - ¹; Discharge specific capacity after 200 cycles: 103.83 mAh·g - ¹, the capacity retention rate is 47.85% of the initial capacity, indicating that the titanium-doped zinc-manganese oxide cathode material has stable cycling performance.
[0051] Figure 9 Titanium-doped ZnMn2O4 in Example 6 at 1 A·g - ¹ Charge-discharge cycle test results: First discharge specific capacity 217.87 mAh·g - ¹, The discharge specific capacity after 50 cycles is 95.91 mAh·g - ¹, The discharge specific capacity after 100 cycles is 92.43 mAh·g -¹, after 200 cycles, it still provides approximately 83.61 mAh·g. - The discharge specific capacity of ¹, with a capacity retention rate of 38.38% of the initial capacity, indicates that this titanium-doped zinc-manganese oxide cathode material has excellent high-current cycling stability.
[0052] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A Ti 4+ Doped ZnMn2O4, characterized in that: The Ti 4+ The Ti replaces the Mn sites in the ZnMn2O4 lattice. 4+ The molar doping amount is 0.3~3%.
2. The Ti according to claim 1 4+ Doped ZnMn2O4, characterized in that: The Ti 4+ The molar doping amount is 0.9~2.1%.
3. The Ti as described in claim 1 or 2 4+ A method for preparing doped ZnMn2O4, characterized in that, include: The zinc source, manganese source, and titanium source were ball-milled and mixed, then calcined to obtain the Ti. 4+ Doped ZnMn2O4.
4. The preparation method according to claim 3, characterized in that: The zinc source is zinc nitrate, zinc acetate, or zinc oxide.
5. The preparation method according to claim 3, characterized in that: The manganese source is manganese nitrate, manganese acetate, manganese carbonate, or manganese oxide.
6. The preparation method according to claim 3, characterized in that: The titanium source is titanium dioxide.
7. The preparation method according to claim 3, characterized in that: The calcination temperature was 600℃ and the time was 3 hours.
8. The preparation method according to claim 7, characterized in that: The heating rate for calcination is 2 °C / min.
9. The Ti as described in claim 1 or 2 4+ The application of doped ZnMn2O4 is characterized by: The Ti 4+ Applications of doped ZnMn2O4 as a cathode material for zinc-ion batteries.