A W 6+ Doped ZnMn2O4, method for its preparation and use as positive electrode material for zinc-ion batteries
By introducing W6+ ion doping into the ZnMn2O4 lattice, the problems of poor conductivity and structural instability of ZnMn2O4 were solved, and a zinc-ion battery cathode material with high specific capacity and good cycle stability was realized.
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
Pure-phase ZnMn2O4, as a cathode material for zinc-ion batteries, suffers from poor intrinsic conductivity, structural collapse during cycling, and manganese ion dissolution, resulting in low specific capacity and poor cycle stability.
W6+ ions were introduced into the Mn sites of the ZnMn2O4 lattice for doping to prepare W6+-doped ZnMn2O4. The high-valence ions enhanced the stability of the lattice structure and promoted charge transport.
It improves the specific capacity and cycle stability of zinc-ion batteries, exhibiting good rate performance and excellent cycle stability.
Smart Images
Figure CN122436482A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of zinc-ion battery cathode materials, specifically relating to a W 6+ Doped ZnMn2O4. Background Technology
[0002] Aqueous zinc-ion batteries (AZIBs) have broad application prospects in large-scale energy storage and portable electronic devices due to their advantages such as abundant resources, low cost, high safety, and environmental friendliness. ZnMn₂O₄, as a typical spinel-type cathode material, has the characteristics of high theoretical capacity and readily available raw materials, making it a research hotspot for cathode materials in aqueous zinc-ion batteries. However, pure-phase ZnMn₂O₄ suffers from poor intrinsic conductivity, structural collapse during cycling, and manganese ion dissolution, resulting in low specific capacity and poor cycle stability, which severely restricts its practical application. Summary of the Invention
[0003] To overcome the aforementioned shortcomings of ZnMn2O4 as a positive electrode material for zinc-ion batteries, this invention provides a W 6+ Doped ZnMn2O4, by introducing heterovalent W at the Mn sites in the ZnMn2O4 lattice. 6+ This significantly improves the specific capacity and cycle stability of zinc-ion batteries.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] A W 6+ Doped ZnMn2O4 is characterized in that: the W 6+ The W replaces the Mn sites in the ZnMn2O4 lattice. 6+ The molar doping amount is 0.3-1.5%.
[0006] Preferably, the W 6+ The molar doping amount is 0.3-0.6%.
[0007] The above W 6+ The preparation method of doped ZnMn2O4 includes: ball milling and mixing zinc source, manganese source and tungsten source, followed by calcination to obtain the W. 6+ Doped ZnMn2O4.
[0008] Preferably, the zinc source is at least one of zinc nitrate, zinc acetate, and zinc oxide.
[0009] Preferably, the manganese source is at least one selected from manganese nitrate, manganese acetate, manganese carbonate, and manganese oxide.
[0010] Preferably, the tungsten source is at least one selected from ammonium metatungstate, tungsten trioxide, and sodium tungstate.
[0011] Preferably, the ball milling is a wet ball milling process.
[0012] Preferably, the calcination temperature is 500-700 °C, the time is 3-5 hours, and the heating rate is 2-5 °C / min. -1 .
[0013] More preferably, the heating rate of the calcination is 2°C / min.
[0014] The above W 6+ Applications of doped ZnMn2O4 as a cathode material for zinc-ion batteries.
[0015] This invention, while maintaining the stability of the ZnMn2O4 spinel main structure, uses high-valence ions W 6+ Doping is introduced into the ZnMn2O4 crystal structure to enhance its stability and suppress the dissolution of manganese ions and structural distortion during charging and discharging; simultaneously, due to W 6+ With a high valence state, it can act as a charge regulation center to promote the charge transport process, enabling the doped ZnMn2O4 cathode material to exhibit high specific capacity, good rate performance and excellent cycle stability in aqueous zinc-ion batteries. Attached Figure Description
[0016] Figure 1 For the present invention W 6+ A schematic diagram of the structure of ZnMn2O4 doped with zinc.
[0017] Figure 2 W prepared in Example 2 6+ X-ray photoelectron spectroscopy (XPS) full spectrum of ZnMn2O4 doped with Zn.
[0018] Figure 3 W prepared in Example 2 6+ X-ray diffraction pattern of ZnMn2O4 doped with Zn.
[0019] Figure 4 W prepared in Example 2 6+ Refined X-ray diffraction pattern of ZnMn2O4 doped with Zn.
[0020] Figure 5 The positive electrode material used was W from Examples 1-5 respectively. 6+ Rate performance of ZnMn2O4-doped coin cells at different current densities.
[0021] Figure 6 The positive electrode materials used were undoped ZnMn2O4 and W from Example 2, respectively. 6+ Cyclic voltammetry curves of ZnMn2O4-doped coin cells at the same scan rate.
[0022] Figure 7 The positive electrode materials used were undoped ZnMn2O4 and W from Example 2, respectively. 6+ Electrochemical impedance spectroscopy of a coin cell doped with ZnMn2O4.
[0023] Figure 8 The positive electrode materials used were undoped ZnMn2O4 and W from Example 2, respectively. 6+ Rate performance of ZnMn2O4-doped coin cells at different current densities.
[0024] Figure 9 The positive electrode material was prepared using W prepared in Example 2. 6+ Coin cells with doped ZnMn2O4 at 0.1 A·g -1 The results of charge-discharge cycle tests were conducted at the specified current density.
[0025] Figure 10 The positive electrode material was prepared using W as described in Example 2. 6+ Coin cells with doped ZnMn2O4 at 1 A·g -1 The results of charge-discharge cycle tests were conducted at the specified current density. Detailed Implementation
[0026] The technical solution of the present invention will be further described in detail below with reference to the embodiments.
[0027] Example 1
[0028] Zinc acetate (Zn(CH3COO)2·2H2O), manganese acetate (Mn(CH3COO)2·4H2O), and ammonium metatungstate ((NH4)6H2W) were prepared respectively. 12 O 40 Weigh the raw materials according to the molar ratio of Zn:Mn:W = 3:6:0.009 (·nH2O). First, manually grind the three raw materials in an agate mortar for 30 minutes to achieve preliminary mixing of the components. Then, transfer the mixture to the agate jar of a planetary ball mill, using a small amount of anhydrous ethanol (2-3 ml) as the dispersion medium, with a ball-to-material ratio of 10:1, at 400 r·min. -1 The mixture was ball-milled at a certain speed for 3 hours. The resulting slurry was then dried in a 60°C electric blast oven for 12 hours to completely remove anhydrous ethanol, yielding a dry and loose mixed powder. The powder was then transferred to a muffle 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 hours. After naturally cooling to room temperature, the powder was removed to obtain W. 6+ ZnMn2O4 cathode material with a molar doping amount of 0.3%.
[0029] Example 2
[0030] Zinc acetate, manganese acetate, and ammonium metatungstate were weighed according to a molar ratio of Zn:Mn:W = 3:6:0.018. The remaining preparation steps were the same as in Example 1, and W was finally obtained. 6+ ZnMn2O4 cathode material with a molar doping content of 0.6%.
[0031] Example 3
[0032] Zinc acetate, manganese acetate, and ammonium metatungstate were weighed according to a molar ratio of Zn:Mn:W = 3:6:0.027. The remaining preparation steps were the same as in Example 1, and W was finally obtained. 6+ ZnMn2O4 cathode material with a molar doping content of 0.9%.
[0033] Example 4
[0034] Zinc acetate, manganese acetate, and ammonium metatungstate were weighed separately according to a molar ratio of Zn:Mn:W = 3:6:0.036. The remaining preparation steps were the same as in Example 1, and W was finally obtained. 6+ ZnMn2O4 cathode material with a molar doping content of 1.2%.
[0035] Example 5
[0036] Zinc acetate, manganese acetate, and ammonium metatungstate were weighed separately according to a molar ratio of Zn:Mn:W = 3:6:0.045. The remaining preparation conditions were the same as in Example 1, and W was finally obtained. 6+ ZnMn2O4 cathode material with a molar doping content of 1.5%.
[0037] Figure 1 For W 6+ A schematic diagram of the structure of doped ZnMn2O4 (W-ZMO). This material has a typical layered stacked structure, in which W is used to replace some of the Mn sites in the lattice for doping, and exhibits a layered feature of alternating Mn(W) layers and Zn layers along the c-axis.
[0038] Figure 2 W prepared in Example 2 6+ X-ray photoelectron spectroscopy (XPS) full spectrum of ZnMn2O4 doped with zinc. The image shows that W 6 + The doped sample showed a W 4f characteristic peak at a binding energy of approximately 36 eV, while the ZnMn2O4 sample did not have this characteristic peak. The Zn 2p, Mn 2p, and O1s characteristic peaks appeared at binding energies of approximately 1020 eV, 640 eV, and 530 eV, respectively, proving that W was successfully doped while Zn, Mn, and O elements maintained their original chemical environments.
[0039] Figure 3 W prepared in Example 26+ The X-ray diffraction pattern of ZnMn2O4, when compared with the standard card PDF#71-2499 in the figure, shows that all the diffraction peaks correspond to the diffraction peaks of ZnMn2O4. The characteristic diffraction peak with 2θ in the range of 30°~40° has the highest intensity. No impurity peaks appear, indicating that the doped material still has a pure phase spinel structure with good crystallinity, and the doping was successful.
[0040] Figure 4 W prepared in Example 2 6+ The refined X-ray diffraction pattern of ZnMn2O4 indicates that W 6+ The Mn sites in the ZnMn2O4 lattice were introduced and replaced. The goodness-of-fit parameter Rwp was refined to 12.35%, which is far below the good fit threshold of 15%. The diffraction peak of the (103) crystal plane was the strongest peak, which proved that the refinement result was reliable. The occupancy of W was consistent with the experimental batch ratio.
[0041] Electrochemical performance
[0042] The W prepared in Examples 1-5 6+ Doped ZnMn2O4 (W x ZnO (x (%) = 0.3-1.5) was used as the positive electrode active material, mixed with conductive agent acetylene black and binder PTFE at a mass ratio of 7:2:1, and anhydrous ethanol was added to grind it into a slurry. The slurry was then coated onto a steel mesh and dried to form a positive electrode sheet. A CR2032 type button cell was assembled using zinc foil as the negative electrode, glass fiber as the separator, and a 2 mol / L ZnSO4 + MnSO4 solution as the electrolyte. Charge-discharge tests were conducted at room temperature, with a voltage range of 0.8-1.8V.
[0043] Figure 5 The positive electrode material used was W from Examples 1-5 respectively. 6+ Rate performance of ZnMn2O4-doped coin cells at different current densities.
[0044] Figure 6 The positive electrode materials were prepared using undoped ZnMn2O4 and W prepared in Example 2, respectively. 6+ Cyclic voltammetry curves of ZnMn2O4-doped coin cells at the same scan rate. Compared with pure ZnMn2O4, the W-doped cells... 6+ The subsequent sample exhibited higher peak current density and smaller inter-peak potential difference, indicating that W 6+ The introduction of [something] effectively reduced the degree of electrode polarization.
[0045] Figure 7 The positive electrode materials were prepared using undoped ZnMn2O4 and W prepared in Example 2, respectively. 6+ Electrochemical impedance spectroscopy (EIS) of a coin cell doped with ZnMn₂O₄. It can be seen that W6+ The charge transfer impedance of doped ZnMn2O4 (25.68 Ω) is significantly lower than that of the undoped sample (69.02 Ω), which is beneficial for Zn... 2+ Fast transmission.
[0046] Figure 8 The positive electrode materials were prepared using undoped ZnMn2O4 and W prepared in Example 2, respectively. 6+ Rate performance of ZnMn2O4-doped coin cells at different current densities. Undoped ZnMn2O4 electrode material at 0.1 A·g -1 At the initial current density, the discharge specific capacity is 149.45 mAh·g. -1 When the current density rises to 0.2 A·g -1 Discharge specific capacity: 134.04 mAh·g -1 0.3A·g -1 117.27mAh·g -1 0.5A·g -1 95.09mAh·g -1 0.8A·g -1 76.92mAh·g -1 1A·g -1 69.48mAh·g -1 2A·g -1 59.4 mAh·g -1 3A·g -1 52.92mAh·g -1 5A·g -1 45.7mAh·g -1 In comparison, W 6+ The ZnMn2O4-doped sample at 0.1 A·g -1 At the initial current density, the discharge specific capacity is 292.25 mAh·g. -1 When the current density rises to 0.2 A·g -1 Discharge specific capacity: 224.04 mAh·g -1 0.3A·g -1 205.62 mAh·g -1 0.5A·g -1 166.85mAh·g -1 0.8A·g -1 134.7 mAh·g -1 1A·g -1 121.97 mAh·g -1 2A·g -1 101.38 mAh·g -1 3A·g -187.91mAh·g -1 5A·g -1 75.13mAh·g -1 After being charged and discharged with a large current, the current density returned to 0.1 A·g. -1 At that time, it still had approximately 251.6 mAh·g -1 The discharge specific capacity and capacity recovery rate of approximately 85.9% indicate that this tungsten-doped zinc-manganese oxide has excellent rate performance.
[0047] Figure 9 The positive electrode material was prepared using W as described in Example 2. 6+ Coin cells doped with ZnMn2O4 at 0.1 A·g -1 The results of charge-discharge cycle tests at the specified current density are as follows: First discharge specific capacity: 304.93 mAh·g -1 The initial charge capacity is 308.53 mAh·g. -1 The coulombic efficiency is approximately 99.35%; the discharge specific capacity after 50 cycles is 255.9 mAh·g. -1 Charging specific capacity 252.84mAh·g -1 The coulombic efficiency is approximately 99.94%; the discharge specific capacity after 100 cycles is 173.65 mAh·g. -1 The discharge specific capacity after 200 cycles is 79.53 mAh·g. -1 The capacity retention rate was 26.46% of the initial capacity, indicating that the tungsten-doped zinc-manganese oxide cathode material has stable cycling performance.
[0048] Figure 10 The positive electrode material was prepared using W as described in Example 2. 6+ Coin cells doped with ZnMn2O4 at 1 A·g -1 The results of charge-discharge cycle tests at the specified current density are as follows: First discharge specific capacity: 122.94 mAh·g -1 The discharge specific capacity after 50 cycles is 92.33 mAh·g. -1 The discharge specific capacity after 100 cycles is 75.55 mAh·g. -1 It can still provide approximately 65.53 mAh·g after 200 cycles. -1 The discharge specific capacity was high, and the capacity retention rate was 53.30% of the initial capacity, indicating that the tungsten-doped zinc manganese oxide cathode material has excellent high-current cycling stability.
[0049] 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 type of W 6+ Doped ZnMn2O4, characterized in that: The W 6+ The W replaces the Mn sites in the ZnMn2O4 lattice. 6+ The molar doping amount is 0.3-1.5%.
2. The W according to claim 1 6+ Doped ZnMn2O4, characterized in that: The W 6+ The molar doping amount is 0.3-0.6%.
3. The W as described in claim 1 or 2 6+ Methods for preparing doped ZnMn2O4 include: Zinc source, manganese source and tungsten source were ball-milled and mixed, then calcined to obtain the W. 6+ Doped ZnMn2O4.
4. The preparation method according to claim 3, characterized in that: The zinc source is at least one of zinc nitrate, zinc acetate, and zinc oxide.
5. The preparation method according to claim 3, characterized in that: The manganese source is at least one of manganese nitrate, manganese acetate, manganese carbonate, and manganese oxide.
6. The preparation method according to claim 3, characterized in that: The tungsten source is at least one of ammonium metatungstate, tungsten trioxide, and sodium tungstate.
7. The preparation method according to claim 3, characterized in that: The ball milling process is a wet ball milling process.
8. The preparation method according to claim 3, characterized in that: The calcination temperature is 500-700 ℃, and the time is 3-5 hours.
9. The preparation method according to claim 8, characterized in that: The heating rate for calcination is 2-5 °C / min.
10. The W as described in claim 1 or 2 6+ The application of doped ZnMn2O4 is characterized by: The W 6+ Applications of doped ZnMn2O4 as a cathode material for zinc-ion batteries.