CN111969199A - Potassium calcium niobate composite salt negative electrode material for potassium ion battery and preparation process thereof - Google Patents
Potassium calcium niobate composite salt negative electrode material for potassium ion battery and preparation process thereof Download PDFInfo
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- CN111969199A CN111969199A CN202010853555.6A CN202010853555A CN111969199A CN 111969199 A CN111969199 A CN 111969199A CN 202010853555 A CN202010853555 A CN 202010853555A CN 111969199 A CN111969199 A CN 111969199A
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- 239000007773 negative electrode material Substances 0.000 title claims abstract description 43
- 229910001414 potassium ion Inorganic materials 0.000 title claims abstract description 38
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 238000002360 preparation method Methods 0.000 title claims description 17
- NYRAVIYBIHCEGB-UHFFFAOYSA-N [K].[Ca] Chemical compound [K].[Ca] NYRAVIYBIHCEGB-UHFFFAOYSA-N 0.000 title description 2
- 239000002131 composite material Substances 0.000 title description 2
- 150000003839 salts Chemical class 0.000 title description 2
- 239000010955 niobium Substances 0.000 claims abstract description 131
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 30
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 29
- 239000011591 potassium Substances 0.000 claims abstract description 28
- 239000010406 cathode material Substances 0.000 claims abstract description 24
- 238000001027 hydrothermal synthesis Methods 0.000 claims abstract description 15
- 238000010438 heat treatment Methods 0.000 claims abstract description 13
- 239000011575 calcium Substances 0.000 claims abstract description 11
- 238000001035 drying Methods 0.000 claims abstract description 11
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 5
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000002243 precursor Substances 0.000 claims abstract description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 3
- 238000002156 mixing Methods 0.000 claims abstract description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000008367 deionised water Substances 0.000 claims description 13
- 229910021641 deionized water Inorganic materials 0.000 claims description 13
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 9
- 239000000047 product Substances 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 8
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 6
- 239000000920 calcium hydroxide Substances 0.000 claims description 6
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 6
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 6
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
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- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 238000006479 redox reaction Methods 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
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- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
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- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- MHEBVKPOSBNNAC-UHFFFAOYSA-N potassium;bis(fluorosulfonyl)azanide Chemical compound [K+].FS(=O)(=O)[N-]S(F)(=O)=O MHEBVKPOSBNNAC-UHFFFAOYSA-N 0.000 description 2
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- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical group [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
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- 238000001354 calcination Methods 0.000 description 1
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Substances [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 1
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- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention belongs to the technical field of potassium ion battery materials, and mainly relates to a method for preparing KCa by combining a hydrothermal method and a solid phase method2Nb3O10A negative electrode material process and application in a potassium ion battery. Mixing a potassium source, a niobium source and a calcium source precursor, carrying out hydrothermal reaction, then carrying out centrifugal treatment, drying and carrying out heat treatment to obtain KCa2Nb3O10And (3) a negative electrode material. The negative electrode material solves the problems that the conventional potassium ion battery negative electrode material is poor in cycle and rate performance, has no stable charging and discharging platform, is serious in battery polarization, is low in charging and discharging coulomb efficiency and the like. Using the KCa of the present invention2Nb3O10The transition metal compound is applied to a charge-discharge voltage platform with stability and high safety, a small over-potential polarization voltage of the battery, high charge-discharge coulombic efficiency and other excellent electrochemical performances of a potassium ion battery cathode material.
Description
Technical Field
The invention belongs to the technical field of potassium ion battery materials, and mainly relates to a lithium ion batteryPreparation of KCa by combining hydrothermal method and solid phase method2Nb3O10A negative electrode material process and application in a potassium ion battery.
Background
Lithium Ion Batteries (LIBs) have been widely used in various portable electronic products since their commercialization in 1990 due to their high energy density and superior electrochemical properties. However, the scarcity of lithium resources makes lithium batteries expensive and unsustainable, and therefore, it is necessary to develop new battery systems. The potassium resource has rich content in the earth crust, uniform distribution, low price and easy obtaining, and the standard electrode potential is similar to lithium, which gives the potassium ion batteries (KIBs) good application prospect. In recent years, KIBs are gradually paid attention by more and more researchers, and have become an important choice for the research of future high-performance battery systems, and the research of related electrode materials and the development of electrolytes are increasing. The transition metal compound can generate reversible oxidation-reduction reaction under specific environment due to the characteristic of multi-valence state of the metal element, and often has higher theoretical potassium storage specific capacity, so that the transition metal compound becomes one of important choices of KIBs cathode materials. Among them, layered transition metal compounds have attracted much attention from researchers in various countries around the world. The compounds have high thermodynamic stability, high crystallinity and high specific surface area, so that the compounds can be applied to different fields, such as clean energy (H is generated by water decomposition)2) (ii) a Electronics (semiconductors and batteries); photovoltaic (solar cells). Wherein, KCa2Nb3O10Is another perovskite niobate transition metal compound with a unique layered structure. In KCa2Nb3O10In the crystal structure, Ca2+And NbO6Octahedral constituent layer matrix, potassium ion sandwiched between Ca2Nb3O10Between the layer substrates. In recent years, KCa2Nb3O10Have been studied by many researchers, although attempts are being made to synthesize KCa having different morphologies by different methods2Nb3O10But inIn most cases, this compound is also predominantly via K2CO3、CaCO3And Nb2O5Prepared by high temperature solid phase reaction at 1200 ℃ (K)2CO3 + 4CaCO3 + 3Nb2O5 = 2KCa2Nb3O10 + 5CO2(g) Can successfully synthesize KCa2Nb3O10Is also characterized by excessive use of K2CO3(excess 10-20%). However, the material synthesized by pure solid phase is often large in particle size, which is not favorable for full contact between the electrode material and the electrolyte. Therefore, the method for synthesizing the electrode material with excellent electrochemical performance by adopting a simple method has very important significance. The hydrothermal rule is to synthesize KCa2Nb3O10The method of (4) requires a lower temperature than the solid phase synthesis method. Generally, the hydrothermal synthesis utilizes high pressure and high temperature to stimulate chemical reaction, and the method is widely applied to synthesis of various organic and inorganic compounds.
At present, KCa2Nb3O10As a negative electrode material, the lithium ion battery and the sodium ion battery have no related reports, but the electrochemical performance of the lithium ion battery and the sodium ion battery is researched to a certain extent in the field of electrocatalysis, and research progress is made to a certain extent. Based on KCa2Nb3O10The unique layered structure can theoretically make the ion size of the K larger+And (4) fast de-intercalation. The invention prepares the nanoscale KCa by adopting a preparation process combining a hydrothermal method and a solid phase method2Nb3O10And first adding KCa2Nb3O10The relevant studies have been made in rechargeable potassium ion batteries as the negative electrode material.
Disclosure of Invention
The invention aims to provide KCa for a potassium ion battery2Nb3O10The negative electrode material and the preparation process thereof overcome the defects of the prior potassium ion batteryThe problems that the charge-discharge coulombic efficiency is low, the charge-discharge platform potential is too high or no stable charge-discharge platform exists, the overpotential polarization is serious and the like are generally encountered by the negative electrode material; the invention is based on KCa2Nb3O10The perovskite niobate negative electrode material for the potassium ion battery has the advantages of high safety, stable charge and discharge potential platform, small overpotential polarization, high charge and discharge coulombic efficiency and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
KCa for potassium ion battery2Nb3O10The preparation method of the negative electrode material comprises the steps of mixing a potassium source, a niobium source and a calcium source precursor, carrying out hydrothermal reaction, then carrying out centrifugal treatment, drying and carrying out heat treatment to obtain KCa2Nb3O10And (3) a negative electrode material.
The method comprises the following steps:
(1) weighing potassium hydroxide (KOH), and pouring the potassium hydroxide (KOH) into a 25 ml polytetrafluoroethylene hydrothermal kettle;
(2) accurately measuring 15 ml of deionized water by using a measuring cylinder, and slowly dropping the deionized water in the measuring cylinder into a hydrothermal kettle filled with potassium hydroxide by using a dropper;
(3) accurately weighing niobium pentoxide Nb2O5Calcium hydroxide Ca (OH)2Pouring the mixture into the hydrothermal kettle, and magnetically stirring;
(4) carrying out hydrothermal reaction;
(5) then cooling to room temperature, opening the hydrothermal kettle to remove supernatant, washing with deionized water, centrifuging in a centrifuge at the rotating speed of 4000 rpm, placing the centrifugal product in a common oven, and drying;
(6) and (3) placing the centrifugally dried product in an air atmosphere tubular furnace for heat treatment, and naturally cooling to room temperature.
Wherein potassium hydroxide KOH and niobium pentoxide Nb2O5Calcium hydroxide Ca (OH)2The dosage relationship is 600: 27: 10 by mass.
In the technical scheme, the magnetic stirring time in the step (3) is preferably 0.5h, so that the compounds are fully mixed;
in the technical scheme, the hydrothermal temperature of 200 ℃ is preferably selected in the step (4), and the reaction time is 72 h;
in the technical scheme, the drying in the step (5) is carried out at the drying temperature of preferably 80 ℃, so that the drying time is 12 hours to avoid the structural deformation of the precursor;
in the technical scheme, the heat treatment temperature in the step (6) is preferably 900 ℃, the reaction time is 72 hours, and the heating rate is controlled to be 1-5 ℃/min, because the heating rate is too high, the structure collapse is easily caused during calcination.
The potassium ion battery KCa2Nb3O10Compared with the existing anode material, the anode material has the following advantages:
(1) the preparation process of the electrode material adopts a hydrothermal method and a solid-phase synthesis method which have the advantages of simple equipment, simple operation steps, environmental protection and easily controlled reaction conditions, and not only shows a good working voltage platform and higher charge-discharge specific capacity, but also has excellent rate performance and cycling stability;
(2) prepared KCa2Nb3O10The anode material is tested in an electrochemical device under the current density of 5 mA/g and the KCa2Nb3O10The first charge-discharge specific capacity of the negative electrode material is 143.8 mAh/g and 80.2 mAh/g respectively, and the first-turn coulombic efficiency is 55.7 percent;
(3) prepared KCa2Nb3O10The reversible potassium storage specific capacity of the negative electrode material can still reach 75.7 mAh/g under the test of electrochemical equipment in the 100 th cycle, the capacity retention rate is 94.38%, the irreversible loss of the specific capacity is only 0.045 mAh/g/circle, the coulombic efficiency is rapidly increased to about 99.98%, and the stable state is kept at the moment.
Drawings
FIG. 1 is KCa prepared2Nb3O10An appearance map;
FIG. 2 is KCa2Nb3O10XRD Rietveld refinement fitting of samplesFigure (Rwp =8.94, Rp =9.05) (a), KCa2Nb3O10Crystal structure diagram (b) (scanning interval: 5 ° -80 °, step length: 0.02 °, scanning rate: 1.5 °/min);
FIG. 3 is KCa2Nb3O10Scanning electron microscope images of;
FIG. 4 is KCa2Nb3O10Transmission electron microscope images and high resolution transmission electron microscope images;
FIG. 5 is KCa2Nb3O10An initial XPS energy spectrum full spectrum (a), an initial pole piece Nb spectrum (b), an Nb spectrum (c) when the discharge is 0.01V, and an Nb spectrum (d) when the charge is 2.5V;
FIG. 6 is KCa2Nb3O10An initial 3-turn cyclic voltammetry characteristic curve graph of the cathode material (the scanning range of the testing voltage is 0.01-3.0V, and the scanning speed is 0.1 mV/s);
FIG. 7 is KCa2Nb3O10A constant current charge-discharge cycle curve chart of the cathode material (test voltage range: 0.01-2.5V, current density: 5 mA/g);
FIG. 8 is KCa2Nb3O10Performance test chart (current density: 5 mA/g) and KCa of negative electrode material after being circulated for 100 circles2Nb3O10A cycle performance test chart (high current density: 30 mA/g) of the cathode material after 140 cycles;
FIG. 9 is KCa2Nb3O10Multiplying power performance test graphs of the negative electrode material under different current densities (the current densities are 5 mA/g, 10 mA/g, 20 mA/g, 50 mA/g, 100 mA/g and 200 mA/g);
FIG. 10 is KCa2Nb3O10A constant current intermittent titration (GITT) test chart (current density: 5 mA/g) of the negative electrode material;
FIG. 11 is KCa2Nb3O10Electrochemical alternating current impedance (EIS) test chart (impedance test frequency range: 105Hz-10-2Hz, scanning amplitude: 5 mV) after the cathode material is completely charged and discharged.
Detailed Description
The invention provides a baseSynthesis of KCa by hydrothermal method and solid phase method combined preparation process2Nb3O10The method comprises the following steps:
(1) 6.7332 g of potassium hydroxide (KOH) were accurately weighed and poured into a (25 ml) polytetrafluoroethylene hydrothermal kettle;
(2) accurately measuring 15 ml of deionized water by using a measuring cylinder, and slowly dropping the deionized water in the measuring cylinder into a hydrothermal kettle filled with potassium hydroxide by using a dropper;
(3) 299.8 mg of niobium pentoxide (Nb) were accurately weighed2O5) 111.4 mg of calcium hydroxide Ca (OH)2Pouring the mixture into the hydrothermal kettle, and magnetically stirring for 0.5 h;
(4) carrying out hydrothermal reaction at 200 ℃ for 72 h;
(5) then cooling to room temperature, opening the hydrothermal kettle to remove supernatant, washing with deionized water, centrifuging in a centrifuge at the rotating speed of 4000 rpm, placing the centrifugal product in a common oven, and drying at 80 ℃ for 12 hours;
(6) placing the centrifugally dried product in a (air atmosphere) tube furnace, carrying out heat treatment at 900 ℃ for 72 hours, and naturally cooling to room temperature to prepare KCa2Nb3O10。
The invention provides a perovskite niobate negative electrode material and a potassium ion battery assembled by the same.
The active substance is perovskite niobate, and the chemical formula of the active substance is KCa2Nb3O10。
KCa of the invention2Nb3O10The negative electrode material is prepared by combining a hydrothermal method and a solid-phase method.
The binder added in the preparation process of the negative pole piece is sodium carboxymethyl cellulose (CMC). Adding CMC into deionized water and stirring for a certain time to make it disperse uniformly to form a viscous liquid, and preparing into a 2 wt% CMC solution for use.
The preparation of the negative pole piece is to use balance to obtain 100 mg KCa2Nb3O10The mixture was placed in a clean mortar, and 20 mg of conductive acetylene black (Super P) was weighed into the mortar, followed by mixed grinding in the mortar for 30 min. After being uniformly mixed, the sample is transferred into a vacuum stirring container, and then a binder (2 wt% CMC solution) is dropwise added according to a certain proportion, so that the negative active material: conductive acetylene black: CMC binder = 7: 2: 1 (wt%: wt%), the container was then placed in a vacuum mixer and stirred for 1 hour, and the stirred slurry was coated on the surface of aluminum foil to maintain the active loading at about 1-2 mg/cm2. After the coating was completed, the aluminum foil was quickly transferred to a vacuum oven at 80 ℃ and continuously dried for 12 hours. Then, the prepared electrode plate is cut into small round pieces with the diameter of 10 mm by using a punching machine, and the small round pieces are quickly weighed so as to prevent the electrode plate from absorbing moisture in the air to cause the weighing error to be enlarged. And putting the weighed electrode plates into a vacuum oven at 100 ℃ again for 12 hours. Then cooled to room temperature and quickly transferred to a glove box for use.
The assembly process of the button cell is completed in a vacuum glove box filled with argon, the oxygen content and the water content of the button cell are both less than 0.1 ppm, a potassium metal block is used as a counter electrode, electrolyte is 5M KFSI (potassium bis-fluorosulfonylimide), solvent is DEGDME (diethylene glycol dimethyl ether), and a cell diaphragm is made of glass fiber produced by Whatman company.
Before the electrochemical test of the button cell, the button cell needs to be kept stand for 12 hours to enable electrolyte to fully soak the pole piece.
The button cells are all placed in a constant temperature box of a low-temperature biochemical incubator for constant temperature test at 28 ℃, so that the influence of external temperature change on the performance of the cells is prevented.
The invention will be further illustrated with reference to the following specific examples. In order to further clarify the present invention, preferred embodiments of the present invention are described in connection with the examples which are intended to illustrate various features and advantages of the present invention, but not to limit the scope of the invention which is not defined by the claims. In addition, it should be understood that various changes or modifications can be made by those skilled in the art after reading the disclosure of the present invention, and such equivalents also fall within the scope of the invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
Example 1:
this example demonstrates a KCa2Nb3O10A method for synthesizing a negative electrode material.
(1) 6.7332 g of potassium hydroxide (KOH) were accurately weighed and poured into a (25 ml) polytetrafluoroethylene hydrothermal kettle;
(2) accurately measuring 15 ml of deionized water by using a measuring cylinder, and slowly dropping the deionized water in the measuring cylinder into a hydrothermal kettle filled with potassium hydroxide by using a dropper;
(3) 299.8 mg of niobium pentoxide (Nb) were accurately weighed2O5) 111.4 mg of calcium hydroxide Ca (OH)2Pouring the mixture into the hydrothermal kettle, and magnetically stirring for 0.5 h;
(4) carrying out hydrothermal reaction at 200 ℃ for 72 h;
(5) then cooling to room temperature, opening the hydrothermal kettle to remove supernatant, washing with deionized water, centrifuging in a centrifuge at the rotating speed of 4000 rpm, placing the centrifugal product in a common oven, and drying at 80 ℃ for 12 hours;
(6) placing the centrifugally dried product in a (air atmosphere) tube furnace, carrying out heat treatment at 900 ℃ for 72 hours, and naturally cooling to room temperature to prepare KCa2Nb3O10。
FIG. 1 is KCa prepared2Nb3O10And (5) apparent images. KCa obtained in this example2Nb3O10Phase identification and microscopic morphology and structure characterization of the negative electrode material are carried out: phase identification is carried out on the prepared cathode material by using a powder X-ray diffractometer and an X-ray photoelectron spectrometer, and microscopic morphology and structural characterization is carried out on the obtained cathode material by using a scanning electron microscope.
FIG. 2 (a) shows the single-phase KCa2Nb3O10The XRD pattern and the corresponding Rietveld refinement optimization result have the scanning interval of 5-80 degrees, the step length of 0.02 degrees and the scanning speed of 1.5 degrees/min. KCa2Nb3O10Belonging to a tetragonal space group and having lattice parameters of a = 7.72A, b = 7.72A and c = 29.46A, respectively. Results of the Experimental tests and KCa2Nb3O10The standard PDF card (PDF # 35-1294) is quite consistent, all Bragg diffraction reflections can be well indexed, which indicates that the purity of the sample is very high, no obvious impurity is generated, and the synthesized material has better crystallinity if the diffraction peak is sharper. Wherein KCa2Nb3O10The peak of the crystal plane of the sample (208) is strongest, which indicates KCa2Nb3O10The sample (208) plane is the dominant crystal plane. In addition, the theoretical value obtained by Rietveld refinement optimization calculation is well matched with the data obtained by experimental tests, wherein R iswp = 8.94, Rp =9.05, further refinement thereof identifies KCa2Nb3O10Purity of the sample. (b) in FIG. 2 is KCa2Nb3O10Crystal structure of (2), KCa2Nb3O10Nb and O form NbO, a typical layered structure material6Octahedral units, Ca2+And NbO6 octahedral make up the layered matrix, with alkali metal (potassium) present in the interlayer forming a layered structure with an interlayer spacing of 6.56 a.
FIG. 3 is KCa2Nb3O10SEM images of sample powder under different electron microscope multiples. The KCa thus prepared is shown in FIGS. (a) and (b)2Nb3O10The nanoparticles all have sharp edges and plate-like morphology associated with the layered structure, and KCa2Nb3O10The sample powder is composed of particles with non-uniform size and irregular shape, the small particles are about 500 nm, and the large particles can reach 1 um. FIG. 3 (c) and (d) are SEM images of the center of the particle taken in FIG. 3 (b), which shows KCa in a further detailed view2Nb3O10Plate-like shape of nanoparticlesMorphology, and from the figure KCa can be seen2Nb3O10The dispersibility of the nanoparticles is not good at normal temperature, so that in the process of preparing the electrode slurry, we need to be careful about KCa2Nb3O10Fully grinding the mixture mixed with the conductive carbon black in a mortar to ensure that the mixture is uniformly dispersed, and further adding KCa2Nb3O10The particle size of the sample is reduced, which is potentially helpful for increasing the contact area between the electrode material and the electrolyte, and is beneficial to K when the electrode material undergoes redox reaction+Thereby improving the electrochemical performance of the battery.
FIG. 4 shows a conventional Transmission Electron Microscopy (TEM) test pattern and a High Resolution Transmission Electron Microscopy (HRTEM) test pattern. Compared with the XRD test method, the scattering of electrons in the material is much stronger than that of X-rays, so that the penetration capability of electron beams becomes very weak, and therefore, the sample is selected to be as thin as possible when being tested. In FIG. 4, (a), (b), and (c) are TEM images at different electron microscope magnifications, and it can be confirmed that KCa is further2Nb3O10Plate-like morphology of nanoparticles, and KCa2Nb3O10The nanoparticles are nanoparticles having a certain thickness. FIG. 4 (d) is a High Resolution Transmission Electron Microscopy (HRTEM) test pattern, in which KCa is shown2Nb3O10The lattice fringes of the nanoparticles are clearly visible, with a lattice spacing of 0.38 nm, corresponding to KCa2Nb3O10And (3) a diffraction surface (200) in an XRD spectrum of the nano-particles. Thus viewed, KCa2Nb3O10Lattice spacing of (2) to K+Is very helpful for storage and diffusion.
FIG. 5 shows KCa2Nb3O10The electrochemical reaction mechanism is further explored by the XPS energy spectrum diagram of the cathode material and the analysis of the valence state of the surface element of the XPS energy spectrum diagram, and the composition of the material components is also confirmed. FIG. 5 (a) is KCa2Nb3O10An XPS full spectrum analysis chart of the initial state of the electrode slice can confirm that the sample mainly contains four elements of K, O, Nb and Ca from the positions of main peaks in the full spectrum. In FIG. 5: (b) KCa for each of (c) and (d)2Nb3O10And the measured results of Nb spectrograms of the electrode plate in the initial state, when the electrode plate is discharged to 0.01V and when the electrode plate is charged to 2.5V all take the C element as the reference of the data measurement of all element binding energy. KCa2Nb3O10In the initial state of the electrode plate, peaks at 209.15 eV and 206.38 eV in the Nb spectrogram respectively correspond to Nb 3d3/2And Nb 3d5/2It shows that Nb is contained in the synthesized material5+Is present. When discharged to 0.01V, peaks at 208.23 eV and 205.41 eV in the Nb spectrogram respectively correspond to Nb 3d3/2And Nb 3d5/2We can find KCa2Nb3O10The binding energy of the Nb element of the negative electrode material is obviously reduced after the potassium is embedded, which shows that the reduction reaction of the negative electrode material is carried out during discharge, so that the valence of the Nb element is reduced, thereby leading to the reduction of the binding energy, and further proves that the material is active. When charged to 2.5V, the binding energy of the corresponding peak in the Nb spectrogram returns to the state before discharge, indicating that KCa2Nb3O10The negative electrode material has reversible redox reaction, and the area of the peak is not much different from that of the peak in the initial state, which indicates that most of Nb atoms are successfully oxidized during charging, which also laterally confirms the reason of good reversibility of the battery.
Example 2:
this example shows a catalyst prepared from a transition metal compound KCa2Nb3O10A potassium ion battery as a negative electrode.
The composition of the potassium ion battery negative electrode material (the mass fraction of the negative electrode material is 100%): so that the anode active material: conductive acetylene black: CMC binder = 7: 2: 1 (wt%: wt%), the container was then placed in a vacuum mixer and stirred for 1 hour, and the stirred slurry was coated on the surface of aluminum foil to maintain the active loading at about 1-2 mg/cm2. After the coating was completed, the aluminum foil was quickly transferred to a vacuum oven at 80 ℃ and continuously dried for 12 hours. Then, the prepared electrode plate is cut into small round pieces with the diameter of 10 mm by using a sheet punching machine and is quickly weighedAnd (4) measuring the quantity so as to prevent the electrode plate from absorbing moisture in the air to cause the weighing error to become large. And putting the weighed electrode plates into a vacuum oven at 100 ℃ again for 12 hours. Then cooled to room temperature and quickly transferred to a glove box for use.
The assembly process of the button cell is completed in a vacuum glove box filled with argon, the oxygen content and the water content of the button cell are both less than 0.1 ppm, a potassium metal block is used as a counter electrode, electrolyte is 5M KFSI (potassium bis-fluorosulfonylimide), solvent is DEGDME (diethylene glycol dimethyl ether), and a cell diaphragm is made of glass fiber produced by Whatman company.
Pressing potassium plate on the gasket, and then stacking the positive electrode shell, the gasket, the pole piece, the glass fiber, the electrolyte (50 μ L), the gasket covered by potassium block, the spring plate and the negative electrode shell in sequence. And sealing the button cell by using an electric packaging machine after the cell is assembled, wherein the packaging pressure is 10 Mpa. Before the electrochemical test of the button cell, the button cell needs to be kept stand for 12 hours to enable the electrolyte to fully soak the pole piece.
The cell obtained in this example was subjected to cyclic voltammetry and galvanostatic charge-discharge tests: the button cells are all placed in a constant temperature box of a low-temperature biochemical incubator for constant temperature test at 28 ℃ to prevent the external temperature change from influencing the performance of the cells, and an electrochemical workstation produced by Bio-Logic Science Instruments is used for carrying out cyclic voltammetry experiments, wherein the scanning range of the test voltage is 0.01-3.0V, and the scanning speed is 0.1 mV/s. Constant current charge and discharge measurement and multiplying power performance test are carried out by a Wuhan blue power LAND CT-2005A battery test system, and the test voltage range is 0.01-2.5V. The constant current intermittent titration method is commonly used for measuring the ion diffusion coefficient, the test is also finished on a charging-discharging tester of the Land CT-2005A model in Wuhan blue, when in test, 5 mA/g current density is adopted for charging-discharging activation for 5 circles, then the battery is allowed to stand for 3 hours, and then discharging (charging) is carried out for 30 minutes, and the steps are repeated until the discharging voltage reaches 0.01V and the charging voltage reaches 2.5V. The test method can obtain the potassium ion diffusion coefficients of the electrode materials under different potentials; the test current density was likewise 5 mA/g. The present study used the Bio-logic electrochemical workstation from Bio-logic Science Instruments for electrochemical AC impedance testing.Impedance test frequency range of 105Hz～10-2Hz。
FIG. 6 is KCa2Nb3O10Initial 3-turn cyclic voltammetry characteristic curve graph (test voltage scanning range: 0.01-3.0V, scanning speed: 0.1 mV/s) of the cathode material, and in the first test period, KCa2Nb3O10Two pairs of reduction peaks with peak potentials of 0.83V and 0.52V, respectively, are present as the anode material, and two pairs of oxidation peaks with peak potentials of 0.52V and 1.37V, respectively, are present when the oxidation reaction occurs, which is in accordance with KCa2Nb3O10In the negative electrode material K+The expulsion is related. In the subsequent two cycles, the reduction peak becomes very weak, while the oxidation peak shifts to a lower pressure and the peak area is reduced, the main cause of this phenomenon being KCa2Nb3O10The nano particle sample is a material with a plate-shaped appearance, potassium ions are quickly embedded and removed, and a part of K is consumed by the formation of an SEI (solid electrolyte interphase) film on the surface of a negative electrode material in the first charge-discharge process of the battery+And K+In KCa2Nb3O10Irreversible intercalation in the lattice, thus leading to insignificant redox peaks in the sample. It can be seen that KCa2Nb3O10The electrochemical reversibility and the cycling stability of the material as the negative electrode material of the potassium ion battery are good.
FIG. 7 shows KCa2Nb3O10Constant current charge-discharge cycle curve of the negative electrode material at a current density of 5 mA/g. The test voltage range is 0.01-2.5V. As shown in FIG. 7 (a), the first cycle of the battery provides 143.8 mAh/g and 80.2 mAh/g of charge-discharge capacity, respectively, and 1.6K is reversibly embedded+The first turn coulombic efficiency was 55.7% due to the Solid Electrolyte Interphase (SEI) generation of the negative electrode material during the first turn of charging, resulting in partial K+Irreversible extraction, which is also a common problem in negative electrode materials for rechargeable batteries. FIG. 7 (b) is a constant current deep charge-discharge cycle graph showing the voltage-specific capacity curves of the 2 nd cycle, the 10 th cycle, the 30 th cycle, the 70 th cycle and the 100 th cycle, respectively, from which it can be seen thatThe specific discharge capacity curves of the batteries from the 2 nd cycle start almost coincide, which indicates that the solid interface material surface film is mainly generated during the first cycle discharge. KCa2Nb3O10When the negative electrode material is deeply charged and discharged in a voltage platform of 0.01-2.5V, the battery has a good voltage platform. In the subsequent circulation, as the circulation times are increased, the reversible potassium specific storage capacity of the battery is in a descending trend in the beginning circulation processes, the reversible potassium specific storage capacity in the 10 th circulation is attenuated to 74.9 mAh/g, the specific capacity is then slightly improved, the reversible potassium specific storage capacity in the 30 th circulation reaches 76.4 mAh/g, the reversible potassium specific storage capacity in the 30 th circulation is in a stable state after the 30 th circulation, the reversible potassium specific storage capacity in the 70 th circulation reaches 76.1 mAh/g, which is almost the same as the reversible potassium storage capacity in the 30 th circulation, except for the inevitable loss of partial capacity due to the formation of an SEI film, the capacity is hardly attenuated between 30 circles and 70 circles, the specific capacity retention rate is still high, the voltage platform is still stable, and the reversible potassium specific storage capacity in the 100 th circle can still reach 75.7 mAh/g, this indicates that KCa2Nb3O10The intercalation compound is applied to the negative electrode material of the potassium ion battery and also shows excellent and stable electrochemical performance.
In FIG. 8, (a) is KCa2Nb3O10The performance test chart of the negative electrode material after 100 cycles under the current density of 5 mA/g shows that KCa2Nb3O10The first charge-discharge specific capacities of the electrode are 143.8 mAh/g and 80.2 mAh/g respectively, and the first-turn coulombic efficiency is 55.7%. During the process from the immediately 2 nd cycle to the 100 th cycle, the overall attenuation of the reversible potassium specific capacity of the battery is not obvious and hardly attenuated, the reversible potassium specific capacity during the 100 th cycle can still reach 75.7 mAh/g, the capacity retention rate is 94.38%, the irreversible loss of the specific capacity is only 0.045 mAh/g/circle, the coulombic efficiency is rapidly increased to about 99.98%, and the specific capacity is always kept in the stable state, and (b) in fig. 8 is KCa2Nb3O10The negative electrode material is cycled for 140 times under the high current density of 30 mA/gAccording to the subsequent cycle performance test chart, the reversible potassium storage specific capacity of the battery is continuously increased in the 140-time cycle process, which shows that the battery is in the continuous activation process under high current density, potassium ions are not completely extracted, the reversible specific capacity in the 140-time cycle is as high as 41.8 mAh/g, and the capacity retention rate is over 100%. Thus, KCa is shown2Nb3O10The negative electrode material also has good cycle stability in the charge-discharge process, which reflects the advantages of the structure of the layered niobate material again.
FIG. 9 shows KCa2Nb3O10The multiplying power performance test chart of the cathode material under different current densities is that the current densities set during the multiplying power performance test are respectively 5 mA/g, 10 mA/g, 20 mA/g, 50 mA/g, 100 mA/g and 200 mA/g. The performance test is carried out under the set current density, and each current density is cycled for 10 times to respectively obtain high reversible potassium storage specific capacities of 69.4, 62.5, 54.95, 42.6, 30.8 and 21.7 mAh/g. At the same time, for KCa2Nb3O10The performance test of current density alternation is carried out for 2-3 times on the cathode material. First, a rate capability test was performed for a small change in current density (5 mA/g → 10 mA/g → 20 mA/g → 50 mA/g → 100 mA/g → 200 mA/g), and the test results were as shown above, and then a rate capability test was performed for a large change in current density (200 mA/g → 5 mA/g → 10 mA/g → 20 mA/g → 50 mA/g → 100 mA/g → 200 mA/g → 5 mA/g), to obtain reversible specific potassium storage capacities of 21.7, 74.2, 67.2, 60.3, 48.5, 39.4, 28.6 and 73.1 mAh/g, respectively. The comparison of the measured reversible potassium storage specific capacity shows that the conversion of the current density only affects the magnitude of the charging specific capacity value, and the influence on the cycling stability of the electrode is not great. It is also surprising that when the current density is changed from 200 mA/g to 5 mA/g, the charge specific capacity of the electrode material in the second cycle can be recovered to 74.2 mAh/g in time and rapidly, and compared with the charge specific capacity (69.4 mAh/g) of the electrode material adjusted by the same current density in the previous cycle, the current density is changed rapidly without affecting the charge reversible specific capacity of the electrode material, and the overall electrochemical performance is better than that of the electrode material adjusted by the same current density in the previous cycleThe electrochemical performance is also improved, even when the current density is alternated for the 3 rd time, the reversible potassium storage specific capacity under the current density of 5 mA/g is hardly attenuated relative to the reversible potassium storage specific capacity under the same current density for the previous time, and the superstrong rate performance is shown. Such good rate performance benefits mainly from two aspects: (1) KCa2Nb3O10The cathode material has a unique layered structure of K+The de-intercalation of (1) provides a powerful environment, (2) the high theoretical specific capacity of the transition metal niobium element and the high reversible redox reaction enable K+Can be more rapidly and reversibly de-intercalated. The two materials ensure that the specific capacity of the electrode material does not generate hysteresis in the rapid current density conversion process, so the material shows excellent rate performance.
FIG. 10 shows KCa2Nb3O10And (3) a constant current intermittent titration (GITT) test chart of the cathode material, wherein during test, 5 mA/g current density charge-discharge activation cycles are adopted, then the battery is allowed to stand for 3 hours, then discharge (charge) is carried out for 30 min, the test current density is also 5 mA/g, and the steps are repeated until the discharge voltage reaches 0.01V and the charge voltage reaches 2.5V. The potassium ion diffusion coefficient of the electrode material under different potentials can be calculated according to Fick's second law from data obtained by the testing method. As shown, the GITT test study gave 10-13-10-12 cm2K of/s+Diffusion coefficient, KCa2Nb3O10The difference between the quasi-equilibrium voltage and the charge-discharge cutoff voltage of the electrode during charge and discharge is large relative to the difference in the low voltage region. During discharge, the diffusion coefficient of potassium ions first drops rapidly to 0.8V with decreasing voltage, after which K+The diffusion coefficient is stable and reaches a maximum value around 0.4V. During charging, the diffusion coefficient of potassium ions rapidly decreases from the beginning of charging, reaches a minimum value at 0.48V, then rapidly increases back up to a maximum value at 0.7V, similar to the results obtained from 4.4.1 Cyclic Voltammetry (CV) analysis. Notably, with KCa2Nb3O10Proceeding of potassium intercalation reaction of cathode material, new phase K1+XCa2Nb3O10Gradually forms, gradually reduces the diffusion coefficient of potassium ions as a whole, and then increases from K1+XCa2Nb3O10To KCa2Nb3O10A similar trend was observed during the reverse phase transition, indicating that potassium ions are becoming more difficult to diffuse during the phase transition. We speculate that this is due to KCa2Nb3O10Middle K+The change of the amount causes K+—K+And K+—KCa2Nb3O10Change of interaction, thereby causing K+A change in diffusion coefficient.
FIG. 11 shows KCa2Nb3O10Electrochemical alternating current impedance (EIS) test chart after the cathode material is completely charged and discharged, wherein the impedance test frequency range is 105Hz-10-2Hz, scanning amplitude 5 mV. Through Electrochemical Impedance Spectroscopy (EIS) analysis, we can further understand K+Intercalation chemical characteristics. The number of test turns is 1 st turn, 3 rd turn and 5 th turn respectively. As can be seen from the graph, the shapes of the impedance test curves are similar, and as the number of cycles increases, the radius of the semicircular area of the battery is gradually reduced during the discharging process, which indicates that the charge transfer resistance value (Rct) is gradually reduced during the discharging process of the battery; during charging, the radius of the front end arch curve is gradually increased due to the increase of the voltage, which indicates that the charge transfer resistance value (Rct) is gradually increased during the charging process of the battery. After a complete charge and discharge, the impedance returns to the state before charge and discharge, which directly indicates that the internal impedance of the battery has a stable and reversible change process in the charge and discharge process. The impedance curve of the 5 th turn was fitted with ZView, and the equivalent circuit diagram is shown in the inset. Wherein Rs, RfRct, CPE and Zw represent electrolyte resistance, contact resistance, charge transfer resistance, constant phase element and Warburg ion diffusion resistance, respectively. Based on the fitting data, we can initially read out the magnitude of the relevant impedance value, contact resistance (R)f) The value of diffusion resistance on the SEI layer was 18.67 Ω. This indicates K+Relatively fast penetration through the SEI layer will be very fastThe electrochemical performance of the battery is greatly improved, and the charge transfer resistance (Rct) is 2143 omega, which is superior to that of graphite (4358). Lower contact resistance (R)f) The synergy with the smaller charge transfer resistance (Rct) may be KCa2Nb3O10The main reasons for the excellent rate capability and the stable cycle performance.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (10)
1. KCa for potassium ion battery2Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: mixing a potassium source, a niobium source and a calcium source precursor, carrying out hydrothermal reaction, then carrying out centrifugal treatment, drying and carrying out heat treatment to obtain KCa2Nb3O10And (3) a negative electrode material.
2. A KCa for potassium ion battery according to claim 12Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: the method comprises the following steps:
(1) weighing potassium hydroxide (KOH), and pouring the potassium hydroxide (KOH) into a 25 ml polytetrafluoroethylene hydrothermal kettle;
(2) accurately measuring 15 ml of deionized water by using a measuring cylinder, and slowly dropping the deionized water in the measuring cylinder into a hydrothermal kettle filled with potassium hydroxide by using a dropper;
(3) accurately weighing niobium pentoxide Nb2O5Calcium hydroxide Ca (OH)2Pouring the mixture into the hydrothermal kettle, and magnetically stirring;
(4) carrying out hydrothermal reaction;
(5) then cooling to room temperature, opening the hydrothermal kettle to remove supernatant, washing with deionized water, centrifuging in a centrifuge at the rotating speed of 4000 rpm, placing the centrifugal product in a common oven, and drying;
(6) and (3) placing the centrifugally dried product in an air atmosphere tubular furnace for heat treatment, and naturally cooling to room temperature.
3. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: wherein potassium hydroxide KOH and niobium pentoxide Nb2O5Calcium hydroxide Ca (OH)2The dosage relationship is 600: 27: 10 by mass.
4. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: and (4) the magnetic stirring time in the step (3) is 0.5 h.
5. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: the temperature of the hydrothermal reaction in the step (4) is 200 ℃, and the reaction time is 72 h.
6. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: and (5) drying at 80 ℃ for 12 h.
7. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: the heat treatment temperature in the step (6) is 900 ℃, and the reaction time is 72 h.
8. A KCa for potassium ion battery according to claim 22Nb3O10The preparation method of the cathode material is characterized by comprising the following steps: and (4) controlling the heating rate of the heat treatment in the step (6) to be 1-5 ℃/min.
9. A KCa prepared by the method of claims 1-82Nb3O10And (3) a negative electrode material.
10. A potassium ion battery comprising KCa prepared by the method of any one of claims 1 to 82Nb3O10And (3) a negative electrode material.
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| CN113666357A (en) * | 2021-08-19 | 2021-11-19 | 中国矿业大学 | Method for preparing carbon cathode of potassium ion battery through multi-step densification and application |
| CN114655984A (en) * | 2022-04-19 | 2022-06-24 | 江苏大学 | Indium-niobium oxide cathode material of lithium ion battery and preparation method thereof |
| CN115558484A (en) * | 2022-10-25 | 2023-01-03 | 扬州大学 | Photochromic material with low molybdenum content and synthesis method thereof |
| CN115612482A (en) * | 2022-10-25 | 2023-01-17 | 扬州大学 | Light-gas synergic color-changing material and synthesis method and application thereof |
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| CN107262085A (en) * | 2017-07-21 | 2017-10-20 | 江苏大学 | A kind of preparation method of bismuth/calcium niobate potassium plasma nano composite |
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2020
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| CN107262085A (en) * | 2017-07-21 | 2017-10-20 | 江苏大学 | A kind of preparation method of bismuth/calcium niobate potassium plasma nano composite |
| JP2019220294A (en) * | 2018-06-18 | 2019-12-26 | トヨタ自動車株式会社 | Aqueous electrolyte solution and aqueous potassium ion battery |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113666357A (en) * | 2021-08-19 | 2021-11-19 | 中国矿业大学 | Method for preparing carbon cathode of potassium ion battery through multi-step densification and application |
| CN114655984A (en) * | 2022-04-19 | 2022-06-24 | 江苏大学 | Indium-niobium oxide cathode material of lithium ion battery and preparation method thereof |
| CN114655984B (en) * | 2022-04-19 | 2024-01-05 | 江苏大学 | Lithium ion battery indium niobium oxide negative electrode material and preparation method thereof |
| CN115558484A (en) * | 2022-10-25 | 2023-01-03 | 扬州大学 | Photochromic material with low molybdenum content and synthesis method thereof |
| CN115612482A (en) * | 2022-10-25 | 2023-01-17 | 扬州大学 | Light-gas synergic color-changing material and synthesis method and application thereof |
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