WO2020114034A1 - 一种二次离子电池层状正极材料及其制备方法和应用 - Google Patents

一种二次离子电池层状正极材料及其制备方法和应用 Download PDF

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Publication number
WO2020114034A1
WO2020114034A1 PCT/CN2019/105750 CN2019105750W WO2020114034A1 WO 2020114034 A1 WO2020114034 A1 WO 2020114034A1 CN 2019105750 W CN2019105750 W CN 2019105750W WO 2020114034 A1 WO2020114034 A1 WO 2020114034A1
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transition metal
ion battery
layer
layered
cathode material
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French (fr)
Inventor
潘锋
翁谋毅
黄伟源
李轶伟
刘嘉杰
陈哲峰
胡宗祥
刘同超
齐瑞
陈聪
林海
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Peking University Shenzhen Graduate School
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Peking University Shenzhen Graduate School
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Definitions

  • the present application relates to the field of secondary ion battery cathode materials, in particular to a secondary ion battery layered cathode material and its preparation method and application.
  • Secondary ion batteries such as lithium ion batteries and sodium ion batteries are energy storage devices that are currently in use and require further development due to their advantages of high operating voltage, high discharge specific capacity, high power, long cycle life, and environmental friendliness.
  • lithium-ion batteries are widely used in a variety of electronic products; but with the rise of new energy vehicles, the energy density and power density of lithium-ion batteries are increasingly demanding.
  • Sodium ion battery has the advantage of low cost and needs further research and development.
  • cathode materials have insufficient energy density and good cycle stability.
  • cathode materials with more applications include layered ternary materials of lithium cobalt oxide, nickel cobalt manganese, and nickel cobalt aluminum, spinel lithium manganate, and phosphoric acid Lithium iron, etc.
  • the discharge specific capacity of these materials is basically less than 250mAh. g-1, lower discharge specific capacity is still a major factor restricting its application in high-energy 3C and power batteries.
  • lithium-rich manganese-based layered material Enriched lithium manganese-based cathode material is reported in the current layer layered Li 2 MnO 3 solid solution with a layered material is formed by LiMO 2, M 2 LiMO in at least one of Ni, Co, Mn of. Both layered Li 2 MnO 3 and layered LiMO 2 have the same oxygen atom arrangement structure and interlayer spacing, and can achieve atomic-level recombination.
  • this traditional lithium-rich manganese-based cathode material is generally charged to a higher voltage in order to exert its high-capacity characteristics, such as greater than 4.6V, a large amount of lithium ions are extracted at high voltage, accompanied by the release of oxygen, thus A serious irreversible phase change is caused, which causes a series of problems such as abrupt voltage decay and capacity loss.
  • the purpose of this application is to provide a new layered cathode material for secondary ion batteries, as well as its preparation method and application.
  • the layered cathode material for a secondary ion battery is composed of a transition metal layer and a lithium layer, or a transition metal layer and a sodium layer; wherein, the transition metal
  • the layer contains at least one hexagonal structural element, the hexagonal structural element is centered on an AO 6 octahedron, six BO 6 octahedrons are arranged on the periphery, and six B ions are arranged as A Ion-centered hexagonal structure; where A is a vacancy or an ion without spin electrons, and B in the six BO 6 octahedrons is the same or different ion with spin electrons.
  • the transition metal layer contains hexagonal structural elements.
  • the layered cathode material of a lithium ion battery composed of a transition metal layer and a lithium layer, whose hexagonal structural element is the center of the AO 6 octahedron is mainly LiO 6 octahedron, forming a Li-6B structural element, or The structural element of the vacancy after Li deintercalation; of course, other metal elements can also be doped according to requirements, that is, other AO 6 octahedral centers, which are not specifically limited here; the Li-6B structure element stabilizes the transition metal layer to a certain extent
  • the layered structure of the material allows the material to be charged to a higher voltage and deintercalates more lithium ions, and the transition metal layer of the Li-6B structure element and the lithium layer are effectively combined, so that the layered cathode material of the lithium ion battery can simultaneously
  • the layered cathode material of the sodium ion battery formed by the transition metal layer and the sodium layer group has the hexagonal structure element AO 6 octahedron center, which is mainly NaO 6 octahedron, forming Na-6B structure element, Or it is the structural element of the vacancy after Na deintercalation; the Na-6B structure element can stabilize the transition metal layer, so that the material can be charged to a higher voltage, deintercalate more Na ions, and finally make the sodium ion battery layered
  • the cathode material has both high energy density and stable cycle performance.
  • the key to the present application is the stabilizing effect of the hexagonal structural elements on the transition metal layer.
  • the center of the AO 6 octahedron it can be LiO 6 octahedron, NaO 6 octahedron or other ions without spin electrons AO 6 octahedron formed.
  • the BO 6 octahedron is mainly arranged around the center of the AO 6 octahedron to form a hexagonal structure.
  • the hexagonal structure is a stable frame structure that allows the A in the AO 6 octahedron to de-embed to form a hexagon at the center of the vacancy Structural primitives, therefore, in principle, BO 6 octahedrons formed by ions with spin electrons are used for the hexagonal structural primitives of the present application.
  • six BO 6 octahedrons are arranged around the center of an AO 6 octahedron.
  • the six BO 6 octahedrons may be the same or different, that is, six BO 6 octahedrons B in the cuboid is a different ion.
  • the ions without spin electrons are selected from Li, Na, K, Mg, Al, As, Sb, Bi, Ti, V, Fe, Co, Cu , Zn, Zr, and Nb; at least one of ions with spin electrons is selected from at least one of Co, Ni, Mn, Fe, V, Ru, Cu, and Cr.
  • the layered ion secondary battery positive electrode material of the present application in order to ensure the function of the transition metal layer, the spin of the present application without AO 6 octahedra centric electronic ions, and with self-BO 6 octahedra
  • the electron-spinning ion is particularly limited.
  • the transition metal layer contains only one hexagonal structural element, that is, all structural elements in one transition metal layer have the same AO 6 octahedron, and the six BO 6 octahedrons in each structural element are the same.
  • transition metal layer in this application contains only one kind of hexagonal structure primitives, which means that all hexagonal structure primitives have the same AO 6 octahedral center and the same surrounding BO 6 octahedron , Not to say that the B in the six BO 6 octahedrons are the same.
  • all AO 6 octahedrons being the same means that A is the same element or part of it is vacant.
  • the transition metal layer contains multiple hexagonal structural elements, that is, one transition metal layer contains multiple AO 6 octahedral and/or multiple BO 6 octahedral hexagonal structural elements.
  • hexagonal structural primitives refer to the hexagonal structural primitives with different AO 6 octahedral centers, or different surrounding BO 6 octahedrons, or AO 6 octahedrons and surrounding BO 6 octahedrons The faces are different.
  • the transition metal layer is entirely formed of hexagonal structural elements, or other polygons formed of hexagonal structural elements doped with at least one of AO 6 octahedron, BO 6 octahedron, Ti and Zr
  • the structure elements are mixed and formed.
  • the transition metal layer contains hexagonal structural elements; in principle, the transition metal layer is entirely formed of hexagonal structural elements. It has better stability effect; however, it is not excluded that other polygonal structure elements can also be doped to form a transition metal layer of a mixed row structure, so that the transition metal layer formed by the mixed row also contains a hexagonal structural group To a certain extent, Yuan also has the effect of improving energy density and stabilizing cycle performance.
  • the layered cathode material of the secondary ion battery is composed of multiple transition metal layers and lithium layers alternately, wherein each transition metal layer is the same or different.
  • the transition metal layer and the lithium layer are stacked in the closest packing or staggered layer.
  • the different transition metal layers mean that the hexagonal structural elements are different, or the arrangement is different.
  • the structural primitives of hexagons are different, for example, one layer is a structural primitive of one or several elements, and the other layer is a structural primitive of another or several elements; the arrangement is different, for example one
  • the layers are all arranged by hexagonal structural elements, and the other layer is hexagonal structural elements and other polygonal structural elements are mixed, or the mixing method or ratio of each layer is different.
  • the layered cathode material of the secondary ion battery is composed of multiple transition metal layers and sodium layers alternately, wherein the transition metal layers of each layer are the same or different.
  • the transition metal layer and the sodium layer are packed in the most densely packed or staggered layer.
  • each transition metal layer in the cathode material of the sodium ion battery is similar to that of the cathode material of the lithium ion battery, and will not be described here.
  • the lithium layer is further doped with at least one of Ni, Mn, Fe, Na, Mg, Al, K, Ca, and Ti elements; the sodium layer It is also doped with at least one of Li, Ni, Mn, Fe, Mg, Al, K, Ca, and Ti elements.
  • the purpose is to stabilize the oxygen price by doping the other elements when the lithium layer is delithiated or the sodium layer is desodiumed, thereby achieving the effect of stabilizing the material structure.
  • all A in the AO 6 octahedron in the hexagonal structure element is Li or vacancy
  • all B in the six BO 6 octahedron is Mn.
  • the transition metal layer is entirely composed of Li-6Mn structural elements formed by LiO 6 octahedron and six MnO 6 , wherein part of the Li-6Mn structural elements may be in a delithiated state; or the transition metal layer is composed of Li-6Mn Structural elements doped with LiO 6 octahedral and/or MnO 6 octahedrons form other polygonal structural elements.
  • the transition metal layer and the lithium layer are stacked in the closest packing or staggered layer stacking, wherein the staggered layer stacking includes twin grain boundaries or O1, O2, O3 At least one of them.
  • Li-6Mn structural element is a more preferred lithium ion battery cathode material structure used in an implementation of the present application, and on the basis of this, other hexagonal structural elements can also be doped, or Replace Li-6Mn with other hexagonal structural elements.
  • the layered cathode material of the secondary ion battery is composed of multiple transition metal layers and lithium layers alternately, in which the A in the AO 6 octahedron of the hexagonal structure element of at least one transition metal layer is all Li, Mg or vacancy, the B in the six BO 6 octahedrons are all Mn, and the A in the AO 6 octahedral in the hexagonal structural element with at least one transition metal layer is Li, Mg, Al, At least one or part of vacancies in Sb, Bi, Ti, V, Fe, Cu, and Zn, and B in the six BO 6 octahedrons is at least one of Ni, Fe, Mn, Co, and V.
  • one transition metal layer is mainly used to provide capacity and obtain higher energy density; the other transition metal layer plays a role of stabilizing structure during charge and discharge. Therefore, by combining the two transition metal layers, a positive electrode material having both high energy density and stable cycle characteristics can be obtained.
  • the stacked transition layers of the multilayer transition metal layer and the lithium layer alternately are the closest packing or the staggered layering, wherein the staggered layering includes twin grain boundaries or O1, O2, Select at least one of the O3 stacking methods.
  • the A in the AO 6 octahedron of the hexagonal structural element of at least one transition metal layer is Li, Na, Mg, Al, Zn, Ti And at least one of the vacancies, B in the six BO 6 octahedrons is at least one of Ni, Fe, Mn, Co, Cu, and V.
  • the formation of this structure in the layered cathode material of the ion battery is beneficial to stabilize the cycle process.
  • the layered cathode material of the secondary ion battery is composed of multiple layers of transition metal layers and sodium layers alternately, and its stacking method is the most densely packed or staggered layering, and the staggered layering includes twin grain boundaries or P1, P2, P3 , O1, O2, O3 at least one of the accumulation methods.
  • the molecular formula of the layered cathode material of the secondary ion battery is: Na a Li b Fe c Mn d Ti e O 2 , where 0.6 ⁇ a ⁇ 0.8, 0.05 ⁇ b ⁇ 0.2, 0.3 ⁇ c ⁇ 0.5, 0.3 ⁇ d ⁇ 0.5, 0.05 ⁇ e ⁇ 0.2.
  • the other side of the application discloses the preparation method of the layered ion battery cathode material of the application, including the use of co-precipitation method, solid phase method, sol-gel method, microwave hydrothermal method, hydrothermal method, ion exchange method and supercritical At least one of the synthesis methods prepares the layered ion battery cathode material; various methods include one or more sintering, and the sintering temperature is 300-1200 degrees Celsius.
  • the preparation method of the present application includes one or more sintering, the purpose of which is to use different temperatures to rearrange the elements to form the desired layered structure, different specific materials have different sintering temperatures, and, sintering The number of times will also affect the crystal structure and properties of the material.
  • Another aspect of the present application discloses a material formed by primary particle nanometerization, secondary particle preparation and modification, surface element doping or surface coating modification of the layered ion battery cathode material of the present application.
  • primary particle nanometerization is mainly to make the layered ion battery cathode material of this application into nanoparticles of a certain size, for example, nanomaterials with a particle diameter of 10nm-500nm, which is beneficial to lithium ion or sodium ion De-embedding speed.
  • the preparation and modification of secondary particles mainly refer to making the particles of the positive electrode material of the layered ion battery of the present application into secondary particles.
  • the secondary particles may be secondary particles formed by re-granulation of primary particles or other particles.
  • Modified secondary particles formed by mixing, for example, the positive electrode material of the layered ion battery of the present application is mixed with conductive particles, conductive nanotubes, conductive nano films or conductive polymers to form closely packed secondary particles.
  • the secondary particles are usually Spherical or quasi-spherical shapes or other shapes are prepared as required, which is beneficial to improve the conductivity of secondary particles and the density per unit volume when preparing electrode pole pieces, thereby improving the charge and discharge speed and energy density of the electrode.
  • Surface element doping refers to the doping of the positive electrode material of the layered ion battery of this application with other metallic or non-metallic elements, which can be determined according to requirements.
  • the shell layer material is used to coat the particles of the layered ion battery cathode material of the present application in the middle, or by adding molecules and/or ions to the electrolyte or solid electrolyte under electrochemical induction
  • the directional interface reaction performs in-situ interface protection; where the shell material can be determined according to requirements, such as oxide or carbon.
  • the metal element is selected from at least one of Ti, Zr and Nb, and the non-metal element is F and/or P.
  • the oxide includes at least one of alumina, lithium titanate, zirconia, titanium oxide, and lithium phosphate.
  • a secondary battery which is a lithium ion secondary battery or a sodium ion secondary battery using the layered positive electrode material of the secondary ion battery of the present application;
  • the layered positive electrode material of the secondary ion battery is mixed with a binder and a conductive agent to form a pole piece, which is used to prepare a lithium ion secondary battery or a sodium ion secondary battery.
  • the key to this application is the improvement of the layered cathode material of the secondary ion battery.
  • the use of the improved cathode material of this application can improve the energy density and cycle performance of the secondary battery.
  • the other components of the secondary battery according to the specific Depending on the type of battery, it is not specifically limited here.
  • specific battery types include, but are not limited to, conventional soft pack batteries, laminated batteries, or wound batteries.
  • the positive electrode material of the present application is generally prepared as a pole piece and applied to a secondary battery.
  • a binder and a conductive agent reference may be made to the prior art, which is not specifically limited herein.
  • the layered cathode material of the secondary ion battery of the present application mainly refers to the cathode material of the lithium ion battery formed by the transition metal layer and the lithium layer when applied to the lithium ion secondary battery; Refers to the anode material of the sodium ion battery formed by the transition metal layer and the sodium layer.
  • the adhesive is PVDF
  • the conductive agent is acetylene black and/or super P
  • the type in which the pole pieces are assembled into a secondary battery is a soft pack battery, a laminated battery, or a wound battery.
  • Another aspect of the present application discloses the application of the secondary battery of the present application in energy storage, 3C electronic products or new energy electric vehicles.
  • the secondary battery of the present application has better energy density and cycle performance due to the use of the positive electrode material of the layered ion battery of the present application, so it can replace the existing secondary battery for energy storage, 3C electronic products or New energy electric vehicles.
  • 3C electronic products are the abbreviations of the three types of electronic products that are conventionally defined as Computer, Communication, and Consumer Electronics.
  • 3C electronic products include but are not limited to mobile phones, notebook computers and tablet computers.
  • the layered cathode material of the secondary ion battery of the present application because the transition metal contains hexagonal structural elements, so that the cathode material can charge and discharge more lithium ions or sodium ions, and has a higher charge and discharge voltage and speed Achieving higher energy density and power density can maintain the stability of the material during charge and discharge cycles. Therefore, the layered cathode material of the secondary ion battery of the present application can have both high energy density and stable cycle performance, which lays the foundation for preparing a high-performance lithium battery or sodium battery.
  • FIG. 1 is a charging and discharging curve diagram of the first circle and the second circle of the lithium-ion battery in Example 1 of the present application;
  • Example 2 is a graph of the cycle performance test result of the lithium ion battery in Example 1 of the present application.
  • Example 3 is a graph of charge and discharge curves of the first lap and the second lap of the lithium-ion battery in Example 2 of the present application;
  • Example 4 is a charge-discharge curve diagram of a lithium ion battery in Example 4 of the present application.
  • Example 5 is a graph of the cycle performance test result of the lithium ion battery in Example 4 of the present application.
  • Example 6 is a graph showing the charging and discharging curves of the first and second laps of the lithium-ion battery in Example 5 of the present application;
  • Example 7 is a graph of the cycle performance test results of the lithium ion battery in Example 5 of the present application.
  • Example 9 is a graph of the cycle performance test results of the lithium ion battery in Example 6 of the present application.
  • Example 10 is a charging and discharging curve diagram of the lithium ion battery in Example 7 of the present application.
  • Example 11 is a graph of the cycle performance test result of the lithium ion battery in Example 7 of the present application.
  • Example 12 is a charge-discharge curve diagram of a lithium ion battery in Example 8 of the present application.
  • Example 13 is a graph of the cycle performance test result of the lithium ion battery in Example 8 of the present application.
  • Example 14 is a charging and discharging curve diagram of the lithium ion battery in Example 9 of the present application.
  • Example 15 is a graph of the cycle performance test result of the lithium ion battery in Example 9 of the present application.
  • Example 16 is a charge-discharge curve diagram of a sodium ion battery in Example 10 of the present application.
  • Example 17 is a graph showing the cycle performance test results of the sodium ion battery in Example 10 of the present application.
  • Example 18 is a charging and discharging curve diagram of the sodium ion battery in Example 11 of the present application.
  • Example 19 is a graph showing the cycle performance test results of the sodium ion battery in Example 11 of the present application.
  • the layered cathode material is a layered solid solution material formed by a transition metal layer and a lithium layer or a sodium layer; the transition metal layer contains At least one hexagonal structural element, the hexagonal structural element is centered on one AO 6 octahedron, six BO 6 octahedrons are arranged on the periphery, and six B ions are arranged to be centered on A ions Hexagonal structure; where A is a vacancy or an ion without spin electrons, and B in the six BO 6 octahedrons is the same or different ion with spin electrons.
  • the layered cathode material of the secondary ion battery of the present application allows more lithium ions or sodium ions to be charged and discharged and has a higher charge and discharge voltage and speed to achieve a higher energy density and power density, and, when delithiating or sodium
  • the hexagonal structural element plays a role of supporting and stabilizing the material structure, and avoids a large change in the phase structure of the material, thereby making the secondary ion battery layered cathode material of the present application have both high energy density and stable cycle performance.
  • the transition metal layer contains hexagonal structural elements.
  • lithium layer, or sodium layer reference may be made to the prior art, which is not specifically limited herein.
  • the composite method of sol-gel method and ion exchange method is used to synthesize the layered cathode material of lithium ion secondary battery.
  • the transition metal layer is composed of Li-6Mn structural elements formed by LiO 6 octahedron and six MnO 6 , There are a large number of staggered layers similar to O1, O2, O3 in the material.
  • the specific preparation method is as follows:
  • the charge and discharge performance test and cycle performance test of the layered cathode material prepared in this example are as follows:
  • the layered cathode material prepared in this example was mixed with acetylene black and a binder (PVDF) at a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) was used as a solvent to make a slurry
  • PVDF acetylene black
  • NMP N-methylpyrrolidone
  • the test voltage range is 1.5-4.8V, and the current density is 10mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces was subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range was 1.5-4.8V, and the current density was 10mA/g.
  • the charging and discharging test results of the first circle and the second circle are shown in Figure 1.
  • the solid line is the charging and discharging curve of the first circle
  • the dotted line is the charging and discharging curve of the second circle.
  • the results in Figure 1 show that the first discharge specific capacity of the material is 350mAh/g, the material has been activated in the first cycle, and the specific discharge capacity in the second cycle is as high as 380mAh/g.
  • the cycle performance test results are shown in Figure 2.
  • the results in Figure 2 show that the material circulates 20 cycles at a current density of 10mA/g within a voltage range of 1.5-4.8V, and the capacity retention rate exceeds 95%. stability.
  • the composite method of solid phase sintering method ie solid phase method
  • ion exchange method is used to synthesize the layered cathode material.
  • the transition metal layer is composed of Li-6Mn structural element doped LiO 6 octahedron and MnO 6 octahedron.
  • Polygon structure primitives are mixed and formed, the specific preparation method is as follows:
  • the charge and discharge performance of the layered positive electrode material of this example was tested in the same way as in Example 1.
  • the test voltage range was 1.3-4.9V.
  • the charging and discharging test results of the first and second laps are shown in Figure 3.
  • the solid line is the charging and discharging curve of the first lap
  • the dotted line is the charging and discharging curve of the second lap.
  • the results in Figure 3 show that the material has a specific discharge capacity of up to 325mAh/g for the first time in the 1.3-4.9V voltage range, and the discharge specific capacity for the second cycle is activated to more than 370mAh/g, which has a very high discharge specific capacity.
  • the composite method of coprecipitation method, solid phase method and ion exchange method is used to prepare the layered cathode material for lithium ion battery.
  • the transition metal layer is formed by Li-6Mn structure element doped LiO6 octahedron and other polygons formed by MnO6 octahedron
  • the structural elements are mixed and arranged.
  • the difference is that the main metal element doped in the lithium layer is Ti 4+ ions, and the doping amount of Ti 4+ ions is 5%.
  • the specific preparation method is as follows:
  • the charge and discharge test results are shown in Figure 4.
  • the results show that the material has a discharge specific capacity of up to 300mAh/g at a current density of 50mA/g in the 1.3-4.9V voltage range, and has a very high discharge specific capacity.
  • a composite method of hydrothermal method, solid phase method, and ion exchange method is used to prepare a layered cathode material for a lithium ion battery.
  • the transition metal layer contains a hexagonal structural element Li-6Mn structural element, and the amount of lithium doped is 25%, the difference is that the prepared ion battery layered cathode material has a primary particle size of 100nm-200nm nano material.
  • the charging and discharging test results of the first and second laps are shown in Figure 6.
  • the solid line is the charging and discharging curve of the first lap
  • the dotted line is the charging and discharging curve of the second lap.
  • the results in Figure 6 show that the material has a very high discharge specific capacity in the 1.3-4.9V voltage range, the first discharge specific capacity and the second cycle discharge specific capacity of 375mAh/g.
  • the cycle performance test is shown in Figure 7.
  • the test results show that the material circulates for 20 cycles at a current density of 10 mA/g, and the capacity decays from the initial 375 mAh/g to 250 mAh/g.
  • the composite method of the sol-gel method and the ion exchange method is used to prepare a layered cathode material for a lithium ion battery.
  • the difference is that the layered cathode material for a lithium ion battery is doped with a non-metallic element F.
  • the specific preparation method is as follows:
  • the charging and discharging test results are shown in Figure 8.
  • the results show that the material has a discharge specific capacity of up to 360mAh/g at a current density of 10mA/g in the 1.3-4.9V voltage range, and has a very high discharge specific capacity.
  • the cycle performance test is shown in Figure 9. The results show that the material has a certain capacity decay in the initial 20-cycle cycle test, and the capacity decays from 360mAh/g to 250mAh/g, while in the cycle test after 20 cycles, the material remains relatively High cycle stability, capacity has been maintained at 250mAh/g.
  • the sol-gel method is used to synthesize the layered cathode material for lithium ion batteries.
  • the transition metal layer has a two-layer structure, one layer is a lithium-doped transition metal Mn layer, and the other layer is a Ni-doped transition metal Sb layer.
  • the layers are most closely packed to form a transition metal layer; and, the Mn layer contains hexagonal structural elements Li-6Mn structural element, and the Sb layer contains hexagonal structural elements Sb-6Ni structural element, two structures The ratio of primitives is 1:1.
  • the specific preparation method is as follows:
  • the charge-discharge performance test and cycle performance test of the layered cathode material of the lithium ion battery prepared in this example are as follows:
  • the lithium ion battery layered cathode material prepared in this example was mixed with acetylene black and a binder (PVDF) at a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) was used as a solvent
  • PVDF acetylene black
  • NMP N-methylpyrrolidone
  • the CR2032 button cell was used to test the electrochemical performance of the material.
  • the Sunway test system is used, with a test voltage range of 1.5-4.6V and a current density of 20mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces is subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range is 1.5-4.6V, and the current density is 20mA/g.
  • the sol-gel method was used to synthesize the layered cathode material for lithium ion batteries.
  • the transition metal layer is a lithium-doped transition metal Mn layer and a Ni-doped transition metal Sb layer, which contain Li-6Mn structural elements and Sb-6Ni, respectively.
  • the structural element is different from Example 7 in that the ratio of the two structural elements is different. In this example, the ratio of the two structural elements is Li-6Mn structural element:Sb-6Ni structural element is 3:1.
  • the specific preparation method is as follows:
  • the charge-discharge performance test and cycle performance test of the layered cathode material of the lithium ion battery prepared in this example are as follows:
  • the lithium ion battery layered cathode material prepared in this example was mixed with acetylene black and a binder (PVDF) at a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) was used as a solvent
  • PVDF acetylene black
  • NMP N-methylpyrrolidone
  • the CR2032 button cell was used to test the electrochemical performance of the material.
  • the Sunway test system is used, with a test voltage range of 1-4.8V and a current density of 20mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces is subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range is 1-4.8V, and the current density is 20mA/g.
  • the charge and discharge test results of the first lap are shown in Figure 12.
  • the results in Fig. 12 show that the specific discharge capacity of the material for the first time is 333mAh/g.
  • the results of the cycle performance test are shown in Figure 13.
  • the results in Figure 13 show that the material circulates 50 cycles at a current density of 20mA/g within a voltage range of 1-4.8V, and the capacity retention rate exceeds 95%. stability.
  • the sol-gel method is used to synthesize the layered cathode material for lithium ion batteries.
  • the transition metal layer has a two-layer structure, one layer is a lithium-doped transition metal Mn layer, and the other layer is a Ni-doped transition metal Al layer.
  • the layers are most closely packed to form a transition metal layer; and, the Mn layer contains hexagonal structural elements Li-6Mn structure element, the Al layer contains hexagonal structural elements Al-6Ni structure element, two structures
  • the ratio of primitives is 3:1, the specific preparation method is as follows:
  • the charge-discharge performance test and cycle performance test of the layered cathode material of the lithium ion battery prepared in this example are as follows:
  • the lithium ion battery layered cathode material prepared in this example was mixed with acetylene black and a binder (PVDF) at a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) was used as a solvent
  • PVDF acetylene black
  • NMP N-methylpyrrolidone
  • the CR2032 button cell was used to test the electrochemical performance of the material.
  • the Sunway test system is used, with a test voltage range of 2-4.8V and a current density of 20mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces is subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range is 2-4.8V, and the current density is 20mA/g.
  • the results of the first round of charge and discharge tests are shown in Figure 14.
  • the results in Fig. 14 show that the specific discharge capacity of the material for the first time is 200mAh/g.
  • the cycle performance test results are shown in Figure 15.
  • the results in Figure 15 show that the material circulates 60 cycles at a current density of 20mA/g within a voltage range of 2-4.8V, and the capacity retention rate exceeds 98%. stability.
  • the solid-phase method was used to synthesize the layered cathode material of sodium ion battery.
  • a in the hexagonal structure element of the transition metal layer is A and Li in the AO 6 octahedron, and B in the six BO 6 octahedron is Mn, Fe, the specific preparation method is as follows:
  • the charge-discharge performance test and cycle performance test of the layered cathode material of the sodium ion battery prepared in this example are as follows:
  • the sodium ion battery layered cathode material prepared in this example was mixed with acetylene black and a binder (PVDF) at a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) was used as a solvent
  • PVDF acetylene black and a binder
  • NMP N-methylpyrrolidone
  • the slurry was prepared, coated on aluminum foil with a spatula, and then dried in a vacuum drying oven at 120 degrees Celsius for 24 hours to obtain pole pieces. Use the prepared pole piece as the positive electrode and the sodium piece as the negative electrode.
  • Whatman glass fiber filter paper GF/C 1822-047 is a separator, 1M NaPF6 was dissolved in a mixed solvent of EC+DEC (volume ratio 1:1) as an electrolyte, and assembled into a CR2032 button cell in a glove box in an argon atmosphere to test the electrochemical performance of the material.
  • the Xinwei test system is used.
  • the voltage range of the first charge and discharge test is 1.5-4.2V, and the current density is 20mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces was subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range was 2-4.2V, and the current density was 200mA/g.
  • the results of the first round of charge and discharge tests are shown in Figure 16.
  • the results show that the specific discharge capacity of the material for the first time is 227mAh/g.
  • the results of the cycle performance test are shown in Figure 17.
  • the results of Figure 17 show that the material circulates 100 cycles at a current density of 200mA/g in a voltage range of 2-4.2V, and the capacity retention rate exceeds 80%. stability.
  • a sol-gel method was used to synthesize a layered cathode material for sodium ion batteries.
  • the transition metal layer is composed of hexagonal Li-6Mn and Mg-6Mn structural elements.
  • the specific preparation method is as follows:
  • the sodium ion battery layered cathode material prepared in this example is mixed with acetylene black and a binder (PVDF) in a mass ratio of 7:2:1, and N-methylpyrrolidone (NMP) is used as a solvent
  • PVDF acetylene black and a binder
  • NMP N-methylpyrrolidone
  • the slurry was prepared, coated on aluminum foil with a spatula, and then dried in a vacuum drying oven at 120 degrees Celsius for 24 hours to obtain pole pieces. Use the prepared pole piece as the positive electrode and the sodium piece as the negative electrode.
  • Whatman glass fiber filter paper GF/C 1822-047 is a separator, 1M NaPF6 was dissolved in a mixed solvent of EC+DEC (volume ratio 1:1) as an electrolyte, and assembled into a CR2032 button cell in a glove box in an argon atmosphere to test the electrochemical performance of the material.
  • the Sunway test system is used, with a test voltage range of 1.5-4.4V and a current density of 15mA/g.
  • Cycling performance test The CR2032 button battery assembled with the above-mentioned pole pieces is subjected to a cyclic performance test on the Sunway test system.
  • the test voltage range is 1.5-4.5V, and the current density is 10mA/g.
  • the results of the first round of charge and discharge tests are shown in Figure 18.
  • the results show that the specific discharge capacity of the material for the first time is 222mAh/g.
  • the results of the cycle performance test are shown in Figure 19.
  • the results in Figure 19 show that the material circulates for 30 cycles at a current density of 10mA/g in the voltage range of 1.5-4.4V, and the capacity retention rate exceeds 70%. stability.
  • the first-principle calculation method is used to simulate the layered cathode material of the lithium ion battery prepared in Example 1.
  • the calculation model is that the transition metal layer is entirely composed of Li-6Mn structural elements, and the transition metal layer Li-Mn atoms When the ratio is 1:3, the lithium layer is completely filled with lithium, and the initial discharge voltage of the material drops due to the existence of stacking faults.
  • the specific calculation method is as follows:
  • the first-principle calculation software Pwmat is used to perform PBE+U calculations on the materials of Example 1 with different phase structures, where the U value of Mn is taken to be 5.0V.
  • the initial lithium removal voltage is calculated to be 4.8V; for the material of the O2 phase, the initial lithium removal voltage is calculated to be 4.4V; for the material of the O1 phase, the initial lithium removal voltage is calculated to be 4.2V .
  • the first-principles calculation method is used to simulate the layered cathode material of the lithium ion battery prepared in Example 1.
  • the calculation model is that the transition metal layer is entirely composed of hexagonal structural elements.
  • the transition metal layer A element and The atomic ratio of element B is 1:2, and the lithium layer is completely filled with lithium.
  • element replacement and structure optimization a possible combination of element A and element B is found, so that A is an ion without spin electrons, and B is with Spin electron ions.
  • the specific calculation methods and results are as follows:
  • the structural element of the transition metal layer is A for Li and B is Mn, and the element replacement is used as the basis.
  • a part of the structure is stable and A does not contain spin electrons, and B contains spin electrons.
  • the calculation results show that the hexagonal structural element of the above structure, which is applied to the layered cathode material of the lithium ion battery, has the equivalent function and effect of the first embodiment.

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Abstract

一种二次离子电池层状正极材料及其制备方法和应用。该层状正极材料由过渡金属层和锂层组成,或由过渡金属层和钠层组成;过渡金属层中含有至少一种六边形结构基元,六边形结构基元以一个AO 6八面体为中心,周边排布六个BO 6八面体,六个B离子排布成以A离子为中心的六边形结构;A为空位或不带自旋电子的离子,六个BO 6八面体中B为相同或不相同的带自旋电子的离子。由于过渡金属中含有六边形的结构基元,使正极材料可充放更多的锂离子或钠离子,并且有更高的充放电电压和速度达到更高能量密度与功率密度,能保持材料在充放电循环时的稳定性。因此,该正极材料能兼具高能量密度和稳定循环性能。

Description

一种二次离子电池层状正极材料及其制备方法和应用 技术领域
本申请涉及二次离子电池正极材料领域,特别是涉及一种二次离子电池层状正极材料及其制备方法和应用。
背景技术
二次离子电池如锂离子电池和钠离子电池由于具有高工作电压、高放电比容量、高功率、长循环寿命和环境友好等优点,是目前正在应用和需要进一步发展的储能器件。目前,锂离子电池被大规模应用于各式各样的电子产品;但是伴随着新能源汽车的兴起,对锂离子电池的能量密度和功率密度提出了越来越高的要求。钠离子电池具有低成本的优势也需要进一步研究和发展。
锂离子电池和钠离子电池的电化学性能与活性材料的性能密不可分。现有的正极材料能量密度不够高和循环稳定性不够好,例如应用比较多的正极材料包括钴酸锂、镍钴锰和镍钴铝的层状三元材料、尖晶石锰酸锂以及磷酸铁锂等,这些材料放电比容量基本都小于250mAh. g-1,较低的放电比容量仍然是制约其在高能3C和动力电池上应用的一个主要因素。
近年来,越来越多的二次电池正极材料研究不仅是过渡金属变价,还有氧的变价材料,通过氧的氧化还原反应实现材料中更多的锂离子脱嵌,从而实现更高的放电比容量。一个典型的例子便是富锂锰基层状材料。目前报道的富锂锰基正极材料是以层状Li 2MnO 3与层状LiMO 2形成的层状固溶体材料,LiMO 2中的M为Ni、Co、Mn中的至少一种。层状Li 2MnO 3与层状LiMO 2两者具有相同的氧原子排布结构和层间距,可以实现原子级别的复合。但是,这种传统的富锂锰基正极材料为了发挥其高容量特性一般要充电到较高的电压,如大于4.6V,在高电压下大量的锂离子脱出,同时伴随有氧的释放,从而造成严重的不可逆相变,引发了急剧的电压衰减和容量损失等一系列问题。
技术问题
本申请的目的是提供一种新的二次离子电池层状正极材料及其制备方法和应用。
技术解决方案
本申请采用了以下技术方案:
本申请的一方面公开了一种二次离子电池层状正极材料,该二次离子电池层状正极材料由过渡金属层和锂层组成,或者由过渡金属层和钠层组成;其中,过渡金属层中含有至少一种六边形的结构基元,六边形的结构基元以一个AO 6八面体为中心,周边排布六个BO 6八面体,且六个B离子排布成以A离子为中心的六边形结构;其中,A为空位或不带自旋电子的离子,六个BO 6八面体中的B为相同或不相同的带自旋电子的离子。
需要说明的是,本申请的二次离子电池层状正极材料,其关键在于过渡金属层内含有六边形的结构基元。例如,过渡金属层和锂层组成的锂离子电池层状正极材料,其六边形的结构基元的AO 6八面体中心,主要为LiO 6八面体,形成Li-6B结构基元,或者为Li脱嵌后的空位的结构基元;当然根据需求还可以掺杂其它金属元素,即其它AO 6八面体中心,在此不作具体限定;Li-6B结构基元在一定程度上稳定过渡金属层的层状结构,使材料可以充电到更高的电压,脱嵌更多的锂离子,并且Li-6B结构基元的过渡金属层和锂层有效结合,使得锂离子电池层状正极材料能够兼具高能量密度和稳定循环性能。同样的,过渡金属层和钠层组的成钠离子电池层状正极材料,其六边形的结构基元的AO 6八面体中心,主要为NaO 6八面体,形成Na-6B结构基元,或者为Na脱嵌后的空位的结构基元;Na-6B结构基元可以稳定过渡金属层,使材料可以充电到更高的电压,脱嵌更多的Na离子,最终使得钠离子电池层状正极材料兼具高能量密度和稳定循环性能。
可以理解,本申请的关键在于六边形的结构基元对过渡金属层的稳定作用,至于AO 6八面体中心,可以是LiO 6八面体、NaO 6八面体或其它不带自旋电子的离子形成的AO 6八面体。BO 6八面体主要是排布在AO 6八面体中心周围形成六边形结构,该六边形结构为稳定的框架结构,允许AO 6八面体中的A脱嵌,形成空位中心的六边形结构基元,因此,原则上带自旋电子的离子形成的BO 6八面体都用于本申请的六边形结构基元。另外,本申请的六边形的结构基元中,一个AO 6八面体中心周围排布六个BO 6八面体,这六个BO 6八面体可以相同,也可以不同,即六个BO 6八面体中的B是不同的离子。
优选的,本申请的二次离子电池层状正极材料中,不带自旋电子的离子选自Li、Na、K、Mg、Al、As、Sb、Bi、Ti、V、Fe、Co、Cu、Zn、Zr和Nb的至少一种;带自旋电子的离子选自Co、Ni、Mn、Fe、V、Ru、Cu和Cr的至少一种。
需要说明的是,本申请的二次离子电池层状正极材料,为了确保过渡金属层的功能,本申请对AO 6八面体中心的不带自旋电子的离子,以及BO 6八面体的带自旋电子的离子进行了特别限定。
优选的,过渡金属层内只含有一种六边形的结构基元,即一个过渡金属层内所有结构基元的AO 6八面体相同,且各结构基元的六个BO 6八面体相同。
需要说明的是,本申请中过渡金属层内只含有一种六边形的结构基元是指,所有六边形的结构基元具有相同的AO 6八面体中心和相同的周围BO 6八面体,并不是说六个BO 6八面体中的B都相同。本申请中,所有AO 6八面体相同是指其A为同一种元素或者部分为空位。
优选的,过渡金属层内含有多种六边形的结构基元,即一个过渡金属层内含有多种AO 6八面体和/或多种BO 6八面体形成的六边形的结构基元。
需要说明的是,多种六边形的结构基元,是指六边形结构基元的AO 6八面体中心不同,或者周围BO 6八面体不同,又或者AO 6八面体和周围BO 6八面体都不同。
优选的,过渡金属层全部由六边形的结构基元形成,或者由六边形的结构基元掺杂AO 6八面体、BO 6八面体、Ti和Zr中的至少一种形成的其它多边形结构基元混排形成。
需要说明的是,本申请的二次离子电池层状正极材料,其关键在于过渡金属层中含有六边形的结构基元;原则上,过渡金属层全部由六边形的结构基元形成可以具有更好的稳定性效果;但是,不排除其中还可以掺杂其它多边形结构基元,形成混排结构的过渡金属层,这样混排形成的过渡金属层中由于也含有六边形的结构基元,在一定程度上也具有提高能量密度和稳定循环性能的作用。
优选的,二次离子电池层状正极材料由多层过渡金属层与锂层交替组成,其中,各层过渡金属层相同或不相同。优选的,过渡金属层与锂层的堆积方式为最密堆积或错层堆积。
需要说明的是,本申请中,各层过渡金属层不相同是指其六边形的结构基元不同,或排布方式不同。其中,六边形的结构基元不同,例如一层为一种或几种元素的结构基元,另一层为另一种或另外几种元素的结构基元;排布方式不同,例如一层为全部由六边形的结构基元排布而成,另一层为六边形的结构基元与其它多边形结构基元混排,或者各层的混排方式或比例不同。
优选的,二次离子电池层状正极材料由多层过渡金属层与钠层交替组成,其中,各层过渡金属层相同或不相同。优选的,钠离子电池正极材料中,过渡金属层与钠层的堆积方式为最密堆积或错层堆积。
需要说明的是,钠离子电池正极材料中各过渡金属层的情况与锂离子电池正极材料类似,在此不累述。
优选的,本申请的二次离子电池层状正极材料中,锂层中还掺杂有Ni、Mn、Fe、Na、Mg、Al、K、Ca和Ti元素中的至少一种;钠层中还掺杂有Li、Ni、Mn、Fe、Mg、Al、K、Ca和Ti元素中的至少一种。
需要说明的是,锂层或钠层中掺杂其它元素,其目的是在锂层脱锂或者钠层脱钠时,通过掺杂的其它元素稳定氧变价,从而达到稳定材料结构的效果,进一步的提高本申请层状离子电池正极材料的能量密度和稳定循环性能。
优选的,二次离子电池层状正极材料中,六边形的结构基元中AO 6八面体中的A全为Li或空位,六个BO 6八面体中的B全为Mn。
优选的,过渡金属层全部由LiO 6八面体与六个MnO 6形成的Li-6Mn结构基元组成,其中,部分Li-6Mn结构基元可以呈脱锂状态;或者过渡金属层由Li-6Mn结构基元掺杂LiO 6八面体和/或MnO 6八面体形成的其它多边形结构基元混排形成。
优选的,二次离子电池层状正极材料中,过渡金属层与锂层的堆积方式为最密堆积或错层堆积,其中,错层堆积包含孪晶晶界或为O1、O2、O3 堆积方式中的至少一种。
需要说明的是,Li-6Mn结构基元是本申请的一种实现方式中采用的较优选的锂离子电池正极材料结构,在此基础上还可以掺杂其它六边形的结构基元,或者采用其它六边形的结构基元替换Li-6Mn。
优选的,二次离子电池层状正极材料由多层过渡金属层与锂层交替组成,其中至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A全为Li、Mg或空位,六个BO 6八面体中的B全为Mn,并且,还有至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A为Li、Mg、Al、Sb、Bi、Ti、V、Fe、Cu和Zn中的至少一种或部分空位,六个BO 6八面体中的B为Ni、Fe、Mn、Co和V中的至少一种。在两种过渡金属层中,其中一种过渡金属层主要用来提供容量,获得更高的能量密度;另一种过渡金属层在充放电过程中起稳定结构的作用。因此,通过两种过渡金属层的相互配合,能够获得兼备高能量密度及稳定循环特性的正极材料。
优选的,二次离子电池层状正极材料中,多层过渡金属层与锂层交替的堆积方式为最密堆积或错层堆积,其中,错层堆积包含孪晶晶界或以O1、O2、O3 堆积方式中选取至少一种的堆积方式。
优选的,本申请的二次离子电池层状正极材料中,至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A为Li、Na、Mg、Al、Zn、Ti和空位中的至少一种,六个BO 6八面体中的B为Ni、Fe、Mn、Co、Cu和V中的至少一种。在离子电池层状正极材料中形成该结构,有利于稳定循环过程。
优选的,二次离子电池层状正极材料由多层过渡金属层与钠层交替组成,其堆积方式为最密堆积或错层堆积,错层堆积包含孪晶晶界或为P1、P2、P3、O1、O2、O3堆积方式中的至少一种。
优选的,二次离子电池层状正极材料的分子式为:Na aLi bFe cMn dTi eO 2,其中0.6≤a≤0.8,0.05≤b≤0.2,0.3≤c≤0.5,0.3≤d≤0.5,0.05≤e≤0.2。该类型的离子电池层状正极材料,过渡金属层的六边形结构基元中AO 6八面体中的A为Li、Ti和Fe,六个BO 6八面体中的B为Mn和/或Fe,有利于材料兼备高能量密度与稳定循环特性。
本申请的另一面公开了本申请的层状离子电池正极材料的制备方法,包括采用共沉淀法、固相法、溶胶凝胶法、微波水热法、水热法、离子交换法和超临界合成法中的至少一种制备层状离子电池正极材料;各种方法中,包括一次或多次烧结,烧结的温度为300-1200摄氏度。
需要说明的是,本申请的制备方法中,包括一次或多次烧结,其目的是利用不同的温度让元素进行重新排列形成所需的层状结构,不同的具体材料烧结温度不同,并且,烧结的次数对材料的晶体结构和性能也会产生影响。
本申请的再一面公开了一种对本申请的层状离子电池正极材料进行一次颗粒纳米化、二次颗粒制备与改性、表面元素掺杂或表面包覆改性形成的材料。
本申请中,一次颗粒纳米化主要是将本申请的层状离子电池正极材料制成一定大小的纳米颗粒,例如制成颗粒粒径为10nm-500nm的纳米材料,有利与锂离子或钠离子的脱嵌速度。二次颗粒制备与改性主要是指将本申请的层状离子电池正极材料的颗粒制成二次颗粒,二次颗粒可以是一次颗粒再造粒形成的二次颗粒,也可以是与其它颗粒混合形成的改性的二次颗粒,例如将本申请的层状离子电池正极材料与导电颗粒、导电纳米管、导电纳米薄膜或导电高分子混合成为紧密堆积的二次颗粒,二次颗粒通常为球形或类球形或者根据需要制备成其它形状,这样有利于提高二次颗粒得到导电性和制备电极极片时的单位体积的密度,从而提高电极的充放电速度及能量密度。表面元素掺杂是指在本申请的层状离子电池正极材料表面掺杂其它金属或非金属元素,具体的可以根据需求而定。表面包覆改性是指,采用壳层材料将本申请的层状离子电池正极材料的颗粒包覆在中间,或者通过在电解液或固态电解质中添加分子和/或离子在电化学诱导下实现定向的界面反应进行原位界面保护;其中壳层材料可以根据需求而定,例如氧化物或碳。
优选的,表面元素掺杂中,金属元素选自Ti、Zr和Nb中的至少一种,非金属元素为F和/或P。
优选的,表面包覆改性中,氧化物包括氧化铝、钛酸锂、氧化锆、氧化钛和磷酸锂中的至少一种。
本申请的再一面公开了一种二次电池,该二次电池为采用本申请的二次离子电池层状正极材料的锂离子二次电池或钠离子二次电池;具体的,将本申请的二次离子电池层状正极材料与粘接剂和导电剂混合,制成极片,用于制备锂离子二次电池或钠离子二次电池。
需要说明的是,本申请的关键在于二次离子电池层状正极材料的改进,采用本申请改进的正极材料能够提高二次电池的能量密度和循环性能,至于二次电池的其它组件根据具体的电池类型而定,在此不作具体限定。例如,具体的电池类型包括但不仅限于常规的软包电池、叠层电池或卷绕电池。另外,本申请的正极材料通常是制备成极片应用于二次电池,极片中的其它组分,例如粘接剂和导电剂都可以参考现有技术,在此不作具体限定。可以理解,本申请的二次离子电池层状正极材料,应用于锂离子二次电池时主要是指过渡金属层和锂层形成的锂离子电池正极材料;应用于钠离子二次电池时主要是指过渡金属层和钠层形成的钠离子电池正极材料。
优选的,粘接剂为PVDF,导电剂为乙炔黑和/或super P;
优选的,极片组装成二次电池的类型为软包电池、叠层电池或卷绕电池。
本申请的再一面公开了本申请的二次电池在储能、3C电子产品或新能源电动汽车中的应用。
可以理解,本申请的二次电池由于采用了本申请的层状离子电池正极材料,具有更好的能量密度和循环性能,因此可以替换现有的二次电池应用于储能、3C电子产品或新能源电动汽车中。其中,3C电子产品是常规定义的计算机(Computer)、通讯(Communication)和消费电子产品(ConsumerElectronic)三类电子产品的简称。
优选的,3C电子产品包括但不仅限于手机、笔记本电脑和平板电脑。
有益效果
本申请的有益效果在于:
本申请的二次离子电池层状正极材料,由于过渡金属中含有六边形的结构基元,使得正极材料可以充放更多的锂离子或钠离子,并且有更高的充放电电压和速度达到更高的能量密度与功率密度,能够保持材料在充放电循环时的稳定性。因此,本申请的二次离子电池层状正极材料能够兼具高能量密度和稳定循环性能,为制备高性能的锂电池或钠电池奠定了基础。
附图说明
图1是本申请实施例一中锂离子电池的首圈和第二圈充放电曲线图;
图2是本申请实施例一中锂离子电池的循环性能测试结果图;
图3是本申请实施例二中锂离子电池的首圈和第二圈充放电曲线图;
图4是本申请实施例四中锂离子电池的充放电曲线图;
图5是本申请实施例四中锂离子电池的循环性能测试结果图;
图6是本申请实施例五中锂离子电池的首圈和第二圈充放电曲线图;
图7是本申请实施例五中锂离子电池的循环性能测试结果图;
图8是本申请实施例六中锂离子电池的充放电曲线图;
图9是本申请实施例六中锂离子电池的循环性能测试结果图;
图10是本申请实施例七中锂离子电池的充放电曲线图;
图11是本申请实施例七中锂离子电池的循环性能测试结果图;
图12是本申请实施例八中锂离子电池的充放电曲线图;
图13是本申请实施例八中锂离子电池的循环性能测试结果图;
图14是本申请实施例九中锂离子电池的充放电曲线图;
图15是本申请实施例九中锂离子电池的循环性能测试结果图;
图16是本申请实施例十中钠离子电池的充放电曲线图;
图17是本申请实施例十中钠离子电池的循环性能测试结果图;
图18是本申请实施例十一中钠离子电池的充放电曲线图;
图19是本申请实施例十一中钠离子电池的循环性能测试结果图。
本发明的实施方式
现有的锂离子电池正极材料或钠离子电池正极材料,为了发挥其高容量特性一般要充电到较高的电压,在高电压下进行大量的锂离子或钠离子脱出时,会因为锂离子或钠离子的大量脱出而产生不可逆的相结构变化,从而引发一系列的问题,影响循环性能。
基于以上问题,本申请创造性的提出了一种新的二次离子电池层状正极材料,该层状正极材料为过渡金属层与锂层或钠层形成的层状固溶体材料;过渡金属层内含有至少一种六边形的结构基元,六边形的结构基元以一个AO 6八面体为中心,周边排布六个BO 6八面体,且六个B离子排布成以A离子为中心的六边形结构;其中,A为空位或不带自旋电子的离子,六个BO 6八面体中的B为相同或不相同的带自旋电子的离子。
本申请的二次离子电池层状正极材料允许充放更多的锂离子或钠离子并且有更高的充放电电压和速度达到更高的能量密度与功率密度,并且,在脱锂或钠时六边形的结构基元起到支撑和稳定材料结构的作用,避免了材料相结构发生较大变化,从而使得本申请的二次离子电池层状正极材料兼具高能量密度和稳定循环性能。
可以理解,本申请的关键在于过渡金属层内含有六边形的结构基元,至于具体的过渡金属层、锂层或钠层的基材可以参考现有技术,在此不作具体限定。
下面通过具体实施例对本申请作进一步详细说明。以下实施例仅对本申请进行进一步说明,不应理解为对本申请的限制。
实施例一
本例采用溶胶凝胶法以及离子交换法的复合方法合成锂离子二次电池的层状正极材料,过渡金属层全部由LiO 6八面体与六个MnO 6形成的Li-6Mn结构基元组成,材料中存在大量的类似O1、O2、O3的错层堆积,具体制备方法如下:
称取1.9g NaAc·3H 2O,0.63g LiAc·2H 2O,3.3gMn(Ac) 2·4H 2O溶解在50mL去离子水中,然后再加入7.6g 聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再于800摄氏度条件下煅烧10h得到前驱体。将上述前驱体与硝酸锂、氯化锂混合均匀,在300摄氏度条件下保温5h,将上述混合物取出后用去离子水反复洗涤,120摄氏度真空干燥12h得到本例的层状锂离子电池正极材料。
对本例制备的层状正极材料进行充放电性能测试和循环性能测试,具体如下:
充放电性能测试:将本实施例所制备层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,锂片做负极,Celgard2400为隔膜,1M LiPF 6溶解在EC+DMC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用新威测试系统,测试电压区间1.5-4.8V,电流密度为10mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间为1.5-4.8V,电流密度为10mA/g。
首圈和第二圈充放电测试结果如图1所示,图1中,实线为首圈的充放电曲线,虚线为第二圈的充放电曲线。图1的结果显示,该材料的首次放电比容量为350mAh/g,材料经过了首圈的活化,第二圈的放电比容量高达380mAh/g。
循环性能测试结果如图2所示,图2的结果显示,该材料在1.5-4.8V电压区间内,在10mA/g电流密度下循环20圈,容量保持率超过95%,具有非常优异的循环稳定性。
实施例二
本例采用固相烧结法(即固相法)以及离子交换法的复合方法合成层状正极材料,过渡金属层由Li-6Mn结构基元掺杂LiO 6八面体和MnO 6八面体形成的其它多边形结构基元混排形成,具体制备方法如下:
称取2g Mn(Ac) 2·4H 2O,0.37g LiAc·2H 2O,0.9g Na 2CO 3,研磨1h将原料混合均匀,在500摄氏度下煅烧3小时,取出样品研细再转入800摄氏度马弗炉中煅烧6h得到前驱。将上述前驱体与硝酸锂、氯化锂混合均匀,在350摄氏度条件下保温4h,将上述混合物取出后用去离子水反复洗涤,120摄氏度真空干燥12h得到本例的锂离子电池层状正极材料。
采用实施例一相同的方法对本例的层状正极材料进行充放电性能测试,测试电压区间为1.3-4.9V。
首圈和第二圈充放电测试结果如图3所示,图3中,实线为首圈的充放电曲线,虚线为第二圈的充放电曲线。图3的结果显示,该材料在1.3-4.9V电压区间内,首次放电比容量高达325mAh/g,第二圈的放电比容量活化到370mAh/g以上,具有非常高的放电比容量。
同样的,按照实施例一相同的方法进行循环性能测试,结果显示,本例的锂离子电池层状正极材料在1.5-4.8V电压区间内,在10mA/g电流密度下循环20圈,容量保持率超过96%,具有非常优异的循环稳定性。
实施例三
本例采用共沉淀法法、固相法以及离子交换法的复合方法制备锂离子电池层状正极材料,过渡金属层由Li-6Mn结构基元掺杂LiO6八面体和MnO6八面体形成的其它多边形结构基元混排形成,所不同的是,锂层中掺杂的主族金属元素为Ti 4+离子,Ti 4+离子掺杂量为5%,具体制备方法如下:
称取3.02g MnSO 4、0.8g钛酸四丁酯溶解在50mL去离子水中,称取1.6g碳酸钠溶于20ml去离子水中,在60摄氏度磁力搅拌状态下,把Na 2CO 3水溶液逐渐滴入MnSO 4和钛酸四丁酯的混合溶液中,连续搅拌8h得到Ti掺杂的碳酸锰前驱。称取1.15g 上述制备的前驱体,0.17g LiAc,0.47g Na 2CO 3,研磨1h将原料混合均匀,在500摄氏度下煅烧3小时,取出样品研细再转入900摄氏度马弗炉中煅烧6h得到前驱。将上述前驱体与硝酸锂、氯化锂混合均匀,在290摄氏度条件下保温4h,将上述混合物取出后用去离子水反复洗涤,120摄氏度真空干燥12h得到本例的锂离子电池层状正极材料。
采用实施例一相同方法测试本例锂离子电池层状正极材料的充放电性能和循环性能。
充放电测试结果如图4所示,结果显示该材料在1.3-4.9V电压区间内,在50mA/g的电流密度下放电比容量高达300mAh/g,具有非常高的放电比容量。
循环性能测试结果如图5所示,结果显示该材料在1.3-4.9V电压区间内,在50mA/g电流密度下循环50圈,容量仍然保持在260mAh/g以上,容量保持率高达85%,具有非常优异的循环稳定性。
实施例四
本例采用水热法、固相法、离子交换法的复合方法制备锂离子电池层状正极材料,过渡金属层含有六边形的结构基元Li-6Mn结构基元,锂的掺杂量为25%,所不同的是,制备的离子电池层状正极材料的一次颗粒粒径为100nm-200nm的纳米材料。
称取0.8g商业化的γ-MnO2粉末加入50ml的内衬聚四氟乙烯的不锈钢水热反应釜中,再往反应釜中加入40ml去离子水,室温下磁力搅拌30min,转入鼓风干燥箱中180摄氏度保温24h,自然冷却,过滤,洗涤,真空干燥12h得到黑色样品前驱。取0.5g 上述前驱、0.09g Li 2CO 3、0.31g Na 2CO 3研磨1h将原料混合均匀,在500摄氏度下煅烧3小时,取出样品研细再转入800摄氏度马弗炉中煅烧12h得到前驱。将上述前驱体与硝酸锂、氯化锂混合均匀,在280摄氏度条件下保温8h,将上述混合物取出后用去离子水反复洗涤,120摄氏度真空干燥12h得到本例的锂离子电池层状正极材料。
采用实施例一相同方法测试本例锂离子电池层状正极材料的充放电性能和循环性能。
首圈和第二圈充放电测试结果如图6所示,图6中,实线为首圈的充放电曲线,虚线为第二圈的充放电曲线。图6的结果显示,该材料在1.3-4.9V电压区间内,首次放电比容量和第二圈的放电比容量375mAh/g,具有非常高的放电比容量。
循环性能测试如图7所示,测试结果显示,该材料在10mA/g 电流密度下循环20圈,容量从最初的375mAh/g衰减到250mAh/g。
实施例五
本例采用溶胶凝胶法以及离子交换法的复合方法制备锂离子电池层状正极材料,所不同的是,制备的锂离子电池层状正极材料掺杂有非金属元素F,具体制备方法如下:
称取1.9g NaAc·3H 2O,0.56g LiAc·2H 2O,0.016g LiF,3.3gMn(Ac) 2·4H 2O溶解在60mL去离子水中,然后再加入6g聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉400摄氏度条件下煅烧3h,取出样品研磨均匀后再在780摄氏度条件下煅烧10h得到前驱体。将上述前驱体与硝酸锂、氯化锂混合均匀,在280摄氏度条件下保温4h,将上述混合物取出后用去离子水反复洗涤,120摄氏度真空干燥12h得到该层状锂离子电池正极材料。
采用实施例一相同方法测试本例锂离子电池层状正极材料的充放电性能和循环性能。
充放电测试结果如图8所示,结果显示该材料在1.3-4.9V电压区间内,在10mA/g的电流密度下放电比容量高达360mAh/g,具有非常高的放电比容量。
循环性能测试如图9所示,结果显示材料在初始的20圈循环测试中存在一定的容量衰减,容量从360mAh/g衰减到250mAh/g,而在20圈以后的循环测试中,材料保持较高的循环稳定性,容量一直保持在250mAh/g。
实施例六
本例采用溶胶凝胶法合成锂离子电池层状正极材料,过渡金属层为两层结构,一层为锂掺杂的过渡金属Mn层,另一层为Ni掺杂的过渡金属Sb层,两层最密堆积形成过渡金属层;并且,Mn层中含有六边形的结构基元Li-6Mn结构基元,Sb层中含有六边形的结构基元Sb-6Ni结构基元,两种结构基元的比例为1:1。具体制备方法如下:
称取2.4045g LiAc·2H 2O,1.6421g Mn(Ac) 2·4H 2O,1.6672g Ni(Ac) 2·4H 2O,1.0271g C 6H 9O 6Sb溶解在50mL去离子水中,然后再加入8.4056g 一水合柠檬酸以及4.4456g 聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再在1100摄氏度条件下煅烧10h得到目标材料。
对本例制备的锂离子电池层状正极材料进行充放电性能测试和循环性能测试,具体如下:
充放电性能测试:将本实施例所制备锂离子电池层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,锂片做负极,Celgard2400为隔膜,1M LiPF6溶解在EC+DMC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用的是新威测试系统,测试电压区间在1.5-4.6V,电流密度为20mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间在1.5-4.6V,电流密度为20mA/g。
首圈的充放电测试结果如图10所示,结果显示,该材料的首次放电比容量为180mAh/g。
循环性能测试结果如图11所示,图11的结果显示,该材料在1.5-4.6V电压区间内,在20mA/g电流密度下循环20圈,容量保持率超过85%,具有非常优异的循环稳定性。
实施例七
本例采用溶胶凝胶法合成锂离子电池层状正极材料,过渡金属层为锂掺杂的过渡金属Mn层以及Ni掺杂的过渡金属Sb层,分别含有Li-6Mn结构基元以及Sb-6Ni结构基元,与实施例七不同之处在于两种结构基元的比例不同,本例中两种结构基元的比例Li-6Mn结构基元:Sb-6Ni结构基元的比例为3:1,具体制备方法如下:
称取2.5763g LiAc·2H 2O,2.4509g Mn(Ac) 2·4H 2O,0.8295g Ni(Ac) 2·4H 2O,0.5136g C 6H 9O 6Sb溶解在50mL去离子水中,然后再加入8.4056g 一水合柠檬酸以及4.4456g聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再在1150摄氏度条件下煅烧10h得到目标材料。
对本例制备的锂离子电池层状正极材料进行充放电性能测试和循环性能测试,具体如下:
充放电性能测试:将本实施例所制备锂离子电池层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,锂片做负极,Celgard2400为隔膜,1M LiPF6溶解在EC+DMC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用的是新威测试系统,测试电压区间在1-4.8V,电流密度为20mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间为1-4.8V,电流密度为20mA/g。
首圈的充放电测试结果如图12所示。图12的结果显示,该材料的首次放电比容量为333mAh/g。循环性能测试结果如图13所示,图13的结果显示,该材料在1-4.8V电压区间内,在20mA/g电流密度下循环50圈,容量保持率超过95%,具有非常优异的循环稳定性。
实施例八
本例采用溶胶凝胶法合成锂离子电池层状正极材料,过渡金属层为两层结构,一层为锂掺杂的过渡金属Mn层,另一层为Ni掺杂的过渡金属Al层,两层最密堆积形成过渡金属层;并且,Mn层中含有六边形的结构基元Li-6Mn结构基元,Al层中含有六边形的结构基元Al-6Ni结构基元,两种结构基元的比例为3:1,具体制备方法如下:
称取2.6534g LiAc·2H 2O,2.4756 Mn(Ac) 2·4H 2O,0.8378 Ni(Ac) 2·4H 2O,0.6314g Al(NO 3) 3溶解在50mL去离子水中,然后再加入8.4056g 一水合柠檬酸以及4.4456g 聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再在800摄氏度条件下煅烧10h得到目标材料。
对本例制备的锂离子电池层状正极材料进行充放电性能测试和循环性能测试,具体如下:
充放电性能测试:将本实施例所制备锂离子电池层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,锂片做负极,Celgard2400为隔膜,1M LiPF6溶解在EC+DMC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用的是新威测试系统,测试电压区间在2-4.8V,电流密度为20mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间在2-4.8V,电流密度为20mA/g。
首圈的充放电测试结果如图14所示。图14的结果显示,该材料的首次放电比容量为200mAh/g。循环性能测试结果如图15所示,图15的结果显示,该材料在2-4.8V电压区间内,在20mA/g电流密度下循环60圈,容量保持率超过98%,具有非常优异的循环稳定性。
实施例九
本例采用固相法合成钠离子电池层状正极材料,过渡金属层的六边形结构基元中AO 6八面体中的A为Li、Ti,六个BO 6八面体中的B为Mn、Fe,具体制备方法如下:
称取3.1797g Na 2CO 3,0.3695g Li 2CO 3,2.3954g Fe 2O 3,3.9468Mn 2O 3,0.799TiO 2,充分研磨1h,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再在900摄氏度条件下煅烧10h得到目标材料。
对本例制备的钠离子电池层状正极材料进行充放电性能测试和循环性能测试,具体如下:
充放电性能测试:将本实施例所制备钠离子电池层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,钠片做负极,whatman玻璃纤维滤纸GF/C 1822-047为隔膜,1M NaPF6溶解在EC+DEC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用的是新威测试系统,首圈充放电测试电压区间在1.5-4.2V,电流密度为20mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间在2-4.2V,电流密度为200mA/g。
首圈的充放电测试结果如图16所示,结果显示,该材料的首次放电比容量为227mAh/g。循环性能测试结果如图17所示,图17的结果显示,该材料在2-4.2V电压区间内,在200mA/g电流密度下循环100圈,容量保持率超过80%,具有非常优异的循环稳定性。
实施例十
本例采用溶胶凝胶法合成钠离子电池层状正极材料,过渡金属层为含有六边形的Li-6Mn与Mg-6Mn结构基元,具体制备方法如下:
称取2.0432g NaAc·3H 2O,0.2267LiAc·2H 2O ,3.8125g Mn(Ac) 2·4H 2O,0.5199gMg(Ac) 2·4H 2O溶解在50mL去离子水中,然后再加入7.4093g聚乙烯吡咯烷酮K30,在90摄氏度下磁力搅拌至溶液呈粘稠的溶胶状,再转移至马弗炉500摄氏度条件下煅烧3h,取出样品研磨均匀后再在850摄氏度条件下煅烧10h得到目标材料。
充放电性能测试:将本实施例所制备钠离子电池层状正极材料与乙炔黑、粘接剂(PVDF)按质量比7:2:1混合均匀,以N-甲基吡咯烷酮(NMP)为溶剂制成浆料,用刮刀涂覆在铝箔上,再在120摄氏度真空干燥箱中干燥24h得到极片。将上述制备好的极片做正极,钠片做负极,whatman玻璃纤维滤纸GF/C 1822-047为隔膜,1M NaPF6溶解在EC+DEC(体积比1:1)的混合溶剂中做电解液,在氩气气氛的手套箱中组装成CR2032扣式电池对材料的电化学性能进行测试。使用的是新威测试系统,测试电压区间在1.5-4.4V,电流密度为15mA/g。
循环性能测试:将用上述极片组装的CR2032扣式电池在新威测试系统上进行循环性能测试,测试电压区间在1.5-4.5V,电流密度为10mA/g。
首圈的充放电测试结果如图18所示,结果显示,该材料的首次放电比容量为222mAh/g。循环性能测试结果如图19所示,图19的结果显示,该材料在1.5-4.4V电压区间内,在10mA/g电流密度下循环30圈,容量保持率超过70%,具有较优异的循环稳定性。
实施例十一
本例采用第一性原理计算方法对实施例一制备得到的锂离子电池层状正极材料进行模拟计算,计算模型为过渡金属层全部由Li-6Mn结构基元组成,过渡金属层Li-Mn原子比为1:3,锂层中全部排满锂,其中,存在层错导致材料的初始放电电压下降。具体计算方法如下:
使用第一性原理计算软件Pwmat对不同相结构的实施例一材料进行PBE+U计算,其中Mn的U值取为5.0V。对于O3相的该材料,计算得到初始脱锂电压为4.8V;对于O2相的该材料,计算得到初始脱锂电压为4.4V;对于O1相的该材料,计算得到初始脱锂电压为4.2V。
计算结果显示,该材料存在的多相复合结构降低初始放电电压。
实施例十二
本例采用第一性原理计算方法对实施例一制备得到的锂离子电池层状正极材料进行模拟计算,计算模型为过渡金属层全部由六边形的结构基元组成,过渡金属层A元素与B元素的原子比为1:2,锂层中全部排满锂,通过元素替换与结构优化,寻找A元素与B元素的可能组合,使得A为不带自旋电子的离子,B为带有自旋电子的离子。具体计算方法与结果如下:
使用第一性原理计算软件PWmat对以Li 2MnO 3 结构,即过渡金属层为A为Li,B为Mn的结构基元,为基础进行元素替换的结构进行结构弛豫与自旋电子计算,得到部分结构稳定且A不含自旋电子,B含有自旋电子的结构共13种分别为:(A,B)=(Al,Cr),(Al,Mn),(As,Mn),(As,Ni),(Bi,Mn),(Bi,Ni),(Co,Cr),(Ga,Cr),(Ga,Mn),(Sb,Mn),(Sb,Ni),(Sc,Cr),(Sc,Mn);通过使用两种元素替换B 得到两种B1元素和B2元素,使得A离子没有自旋电子,B1和B2离子都有自旋电子的组合共264种,分别为:(A,B1,B2)=(Ag,Cr,Mo),(Ag,Cr,V),(Ag,Mn,Mo),(Ag,Mo,Mn),(Ag,Nb,Mo),(Ag,Pd,Mo),(Ag,Pd,Mo),(Ag,Ru,Mn),(Ag,Ru,V),(Ag,Ti,Mo),(Ag,Ti,Nb),(Ag,Ti,Nb),(Ag,V,Cr),(Ag,V,Mn),(Ag,V,Mo),(Be,Co,Cr),(Be,Co,Mo),(Be,Cr,Co),(Be,Cr,Mn),(Be,Cr,Mo),(Be,Cr,Nb),(Be,Cr,Rh),(Be,Cr,Ru),(Be,Cr,V),(Be,Fe,Cr),(Be,Fe,Mn),(Be,Fe,Mo),(Be,Fe,Nb),(Be,Fe,V),(Be,Mn,V),(Be,Rh,Cr),(Be,Sb,Nb),(Be,Ti,Mo),(Be,Ti,Nb),(Be,Ti,V),(Be,Ti,Zr),(Be,Zr,Mo),(Be,Zr,Nb),(Be,Zr,Ti),(Ca,Co,Cr),(Ca,Cr,Co),(Ca,Cr,Mn),(Ca,Cr,Mo),(Ca,Cr,Nb),(Ca,Cr,Rh),(Ca,Cr,Ru),(Ca,Cr,V),(Ca,Fe,Cr),(Ca,Fe,Mn),(Ca,Fe,Mo),(Ca,Fe,Nb),(Ca,Fe,V),(Ca,Mn,V),(Ca,Ni,V),(Ca,Rh,Cr),(Ca,Ti,Mo),(Ca,Ti,Nb),(Ca,Ti,Zr),(Ca,Zr,Mo),(Cd,Co,Cr),(Cd,Co,Mn),(Cd,Co,Mo),(Cd,Cr,Co),(Cd,Cr,Mn),(Cd,Cr,Mo),(Cd,Cr,Nb),(Cd,Cr,Rh),(Cd,Cr,Ru),(Cd,Cr,V),(Cd,Fe,Cr),(Cd,Fe,Mn),(Cd,Fe,Mo),(Cd,Fe,Nb),(Cd,Fe,V),(Cd,Mn,V),(Cd,Ni,V),(Cd,Rh,Cr),(Cd,Ti,Mo),(Cd,Ti,Nb),(Cd,Zr,Nb),(Co,Cr,Ni),(Cu,Ti,Nb),(Cu,Ti,Nb),(K,Co,Cr),(K,Co,Cr),(K,Co,Mn),(K,Co,Mo),(K,Co,Mo),(K,Cr,Mn),(K,Cr,Mo),(K,Cr,V),(K,Mn,Cr),(K,Mn,Mo),(K,Mo,Mn),(K,Nb,Mo),(K,Pd,Mo),(K,Pd,Mo),(K,Rh,Cr),(K,Rh,Mn),(K,Ru,Cr),(K,Ru,Mn),(K,Ru,V),(K,Ti,Nb),(K,Ti,Nb),(K,V,Cr),(K,V,Mn),(K,V,Mo),(Mg,Co,Cr),(Mg,Co,Mo),(Mg,Cr,Co),(Mg,Cr,Mn),(Mg,Cr,Mo),(Mg,Cr,Nb),(Mg,Cr,Rh),(Mg,Cr,Ru),(Mg,Cr,V),(Mg,Fe,Cr),(Mg,Fe,Mn),(Mg,Fe,Mo),(Mg,Fe,Nb),(Mg,Fe,V),(Mg,Mn,V),(Mg,Ni,V),(Mg,Rh,Cr),(Mg,Ti,Mo),(Mg,Ti,Nb),(Mg,Zr,Mo),(Mg,Zr,Nb),(Na,Co,Cr),(Na,Co,Cr),(Na,Co,Mn),(Na,Cr,Mn),(Na,Cr,Mo),(Na,Cr,V),(Na,Mn,Cr),(Na,Mn,Mo),(Na,Mo,Mn),(Na,Nb,Mo),(Na,Pd,Mo),(Na,Pd,Mo),(Na,Rh,Cr),(Na,Rh,Mn),(Na,Ru,Cr),(Na,Ru,Mn),(Na,Ru,V),(Na,Ti,Mo),(Na,Ti,Nb),(Na,Ti,Nb),(Na,V,Cr),(Na,V,Mn),(Na,V,Mo),(Pd,Cr,Ni),(Pd,Fe,Ni),(Sc,Cr,Fe),(Sc,Ti,Cr),(Sc,Ti,Fe),(Sc,Ti,Zr),(Sn,Co,Cr),(Sn,Co,Mo),(Sn,Co,Nb),(Sn,Co,Nb),(Sn,Co,Pd),(Sn,Co,Ti),(Sn,Co,V),(Sn,Co,V),(Sn,Cr,Co),(Sn,Cr,Mn),(Sn,Cr,Mo),(Sn,Cr,Nb),(Sn,Cr,Ni),(Sn,Cr,Pd),(Sn,Cr,Rh),(Sn,Cr,Ti),(Sn,Cr,V),(Sn,Cr,Zr),(Sn,Fe,Co),(Sn,Fe,Cr),(Sn,Fe,Mn),(Sn,Fe,Mo),(Sn,Fe,Nb),(Sn,Fe,Ni),(Sn,Fe,Pd),(Sn,Fe,Ru),(Sn,Fe,S),(Sn,Fe,Se),(Sn,Fe,Ti),(Sn,Fe,V),(Sn,Fe,V),(Sn,Fe,Zr),(Sn,Mn,Nb),(Sn,Mn,V),(Sn,Ni,Nb),(Sn,Ni,V),(Sn,Pd,V),(Sn,Rh,Cr),(Sn,Rh,Mo),(Sn,Rh,Nb),(Sn,Sb,Nb),(Sn,Sc,Nb),(Sn,Sc,Zr),(Sn,Ti,Co),(Sn,Ti,Cr),(Sn,Ti,Mn),(Sn,Ti,Mo),(Sn,Ti,Nb),(Sn,Ti,Ni),(Sn,Ti,Te),(Sn,Ti,V),(Sn,Ti,Zr),(Sn,Y,Nb),(Sn,Zr,Co),(Sn,Zr,Cr),(Sn,Zr,Mn),(Sn,Zr,Nb),(Sn,Zr,Ti),(Sn,Zr,V),(Sr,Co,Cr),(Sr,Co,Mn),(Sr,Co,Mo),(Sr,Co,Nb),(Sr,Co,V),(Sr,Cr,Co),(Sr,Cr,Mn),(Sr,Cr,Mo),(Sr,Cr,Nb),(Sr,Cr,Rh),(Sr,Cr,Ru),(Sr,Cr,V),(Sr,Fe,Cr),(Sr,Fe,Mn),(Sr,Fe,Mo),(Sr,Fe,Nb),(Sr,Fe,V),(Sr,Mn,V),(Sr,Rh,Cr),(Sr,Ti,Mo),(Ti,Cr,Co),(Ti,Fe,Co),(Y,Cr,Fe),(Y,Ti,Cr),(Y,Ti,Fe),(Zn,Co,Cr),(Zn,Cr,Co),(Zn,Cr,Mn),(Zn,Cr,Mo),(Zn,Cr,Nb),(Zn,Cr,Rh),(Zn,Cr,Ru),(Zn,Cr,V),(Zn,Fe,Cr),(Zn,Fe,Mn),(Zn,Fe,Mo),(Zn,Fe,Nb),(Zn,Fe,V),(Zn,Mn,V),(Zn,Ni,V),(Zn,Rh,Cr),(Zn,Ti,Mo),(Zn,Ti,Nb),(Zn,Zr,Mo),(Zn,Zr,Nb),(Zr,Cr,Co),(Zr,Cr,Rh),(Zr,Fe,Co)。
计算结果显示,以上结构的六边形的结构基元,应用于锂离子电池层状正极材料都具有实施例一相当的功能和效果。
以上内容是结合具体的实施方式对本申请所作的进一步详细说明,不能认定本申请的具体实施只局限于这些说明。对于本申请所属技术领域的普通技术人员来说,在不脱离本申请构思的前提下,还可以做出若干简单推演或替换。

Claims (10)

  1. 一种二次离子电池层状正极材料,其特征在于:所述二次离子电池层状正极材料由过渡金属层和锂层组成,或者由过渡金属层和钠层组成;
    所述过渡金属层中含有至少一种六边形的结构基元,所述六边形的结构基元是以一个AO 6八面体为中心,周边排布六个BO 6八面体,且六个B离子排布成以A离子为中心的六边形结构;
    其中,A为空位或不带自旋电子的离子,六个BO 6八面体中的B为相同或不相同的带自旋电子的离子。
  2. 根据权利要求1所述的二次离子电池层状正极材料,其特征在于:所述不带自旋电子的离子选自Li、Na、K、Mg、Al、As、Sb、Bi、Ti、V、Fe、Co、Cu、Zn、Zr和Nb的至少一种;
    所述带自旋电子的离子选自Co、Ni、Mn、Fe、V、Ru、Cu和Cr的至少一种;
    优选的,所述过渡金属层内只含有一种六边形的结构基元,即一个过渡金属层内所有结构基元的AO 6八面体相同,且各结构基元的六个BO 6八面体相同;
    优选的,所述过渡金属层内含有多种六边形的结构基元,即一个过渡金属层内含有多种AO 6八面体和/或多种BO 6八面体形成的六边形的结构基元;
    优选的,所述过渡金属层全部由六边形的结构基元形成,或者由六边形的结构基元掺杂AO 6八面体、BO 6八面体、Ti和Zr中的至少一种形成的其它多边形结构基元混排形成;
    优选的,所述二次离子电池层状正极材料由多层过渡金属层与锂层交替组成,其中,各层过渡金属层相同或不相同;优选的,过渡金属层与锂层的堆积方式为最密堆积或错层堆积;
    优选的,所述二次离子电池层状正极材料由多层过渡金属层与钠层交替组成,其中,各层过渡金属层相同或不相同;优选的,过渡金属层与钠层的堆积方式为最密堆积或错层堆积。
  3. 根据权利要求1所述的二次离子电池层状正极材料,其特征在于:所述锂层中还掺杂有Ni、Mn、Fe、Na、Mg、Al、K、Ca和Ti元素中的至少一种;所述钠层中还掺杂有Li、Ni、Mn、Fe、Mg、Al、K、Ca和Ti元素中的至少一种。
  4. 根据权利要求1-3任一项所述的二次离子电池层状正极材料,其特征在于:所述二次离子电池层状正极材料中,六边形的结构基元中AO 6八面体中的A全为Li或全为空位,六个BO 6八面体中的B全为Mn;
    优选的,所述过渡金属层全部由LiO 6八面体与六个MnO 6形成的Li-6Mn结构基元组成,其中,部分Li-6Mn结构基元可以呈脱锂状态;或者过渡金属层由Li-6Mn结构基元掺杂LiO 6八面体和/或MnO 6八面体形成的其它多边形结构基元混排形成;
    优选的,所述二次离子电池层状正极材料中,过渡金属层与锂层的堆积方式为最密堆积或错层堆积;
    优选的,所述错层堆积包含孪晶晶界或为O1、O2、O3 堆积方式中的至少一种。
  5. 根据权利要求1-3任一项所述的二次离子电池层状正极材料,其特征在于:所述二次离子电池层状正极材料由多层过渡金属层与锂层交替组成,其中至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A全为Li、Mg或空位,六个BO 6八面体中的B全为Mn;并且,还有至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A为Li、Mg、Al、Sb、Bi、Ti、V、Fe、Cu和Zn中的至少一种或部分空位,六个BO 6八面体中的B为Ni、Fe、Mn、Co和V中的至少一种;
    优选的,所述二次离子电池层状正极材料中,多层过渡金属层与锂层交替的堆积方式为最密堆积或错层堆积;
    优选的,所述错层堆积包含孪晶晶界或以O1、O2、O3 堆积方式中选取至少一种的堆积方式。
  6. 根据权利要求1-3任一项所述的二次离子电池层状正极材料,其特征在于:所述二次离子电池层状正极材料中,至少一层过渡金属层的六边形的结构基元中AO 6八面体中的A为Li、Na、Mg、Al、Zn、Ti和空位中的至少一种,六个BO 6八面体中的B为Ni、Fe、Mn、Co、Cu和V中的至少一种;
    优选的,所述二次离子电池层状正极材料由多层过渡金属层与钠层交替组成,其堆积方式为最密堆积或错层堆积,所述错层堆积包含孪晶晶界或为P2、P3、O1、O2、O3堆积方式中的至少一种;
    优选的,所述二次离子电池层状正极材料的分子式为:Na aLi bFe cMn dTi eO 2,其中0.6≤a≤0.8,0.05≤b≤0.2,0.3≤c≤0.5,0.3≤d≤0.5,0.05≤e≤0.2。
  7. 根据权利要求1-6任一项所述的二次离子电池层状正极材料的制备方法,其特征在于:包括采用共沉淀法、固相法、溶胶凝胶法、微波水热法、水热法、离子交换法和超临界合成法中的至少一种制备层状正极材料;各种方法中,包括一次或多次烧结,烧结的温度为300-1200摄氏度。
  8. 一种对权利要求1-6任一项所述的二次离子电池层状正极材料进行一次颗粒纳米化、二次颗粒制备与改性、表面元素掺杂或表面包覆改性形成的材料;
    优选的,所述一次颗粒纳米化,包括将所述层状离子电池正极材料制备成颗粒粒径为10nm-500nm的纳米材料;
    优选的,所述二次颗粒制备与改性,包括将所述层状离子电池正极材料与导电颗粒、导电纳米管、导电纳米薄膜或导电高分子混合成为紧密堆积的二次颗粒;优选的,所述二次颗粒为球形或类球形;
    优选的,所述表面元素掺杂,包括将金属元素和/或非金属元素掺杂在所述层状离子电池正极材料的颗粒表面,所述金属元素选自Ti、Zr和Nb中的至少一种,所述非金属元素为F和/或P;
    优选的,所述表面包覆改性,包括将氧化物或碳包覆在所述层状离子电池正极材料的颗粒表面,或通过在电解液或固态电解质中添加分子和/或离子在电化学诱导下实现定向的界面反应进行原位界面保护;优选的,所述氧化物包括氧化铝、钛酸锂、氧化锆、氧化钛和磷酸锂中的至少一种。
  9. 一种二次电池,其特征在于:所述二次电池为采用权利要求1-6任一项所述的二次离子电池层状正极材料的锂离子二次电池或钠离子二次电池;具体的,将权利要求1-6任一项所述的二次离子电池层状正极材料与粘接剂和导电剂混合,制成极片,用于制备锂离子二次电池或钠离子二次电池;
    优选的,所述粘接剂为PVDF,所述导电剂为乙炔黑和/或super P;
    优选的,极片组装成二次电池的类型为软包电池、叠层电池或卷绕电池。
  10. 根据权利要求9所述的二次电池在储能、3C电子产品或新能源电动汽车中的应用;
    优选的,所述3C电子产品包括手机、笔记本电脑和平板电脑。
PCT/CN2019/105750 2018-12-07 2019-09-12 一种二次离子电池层状正极材料及其制备方法和应用 Ceased WO2020114034A1 (zh)

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