Pure cation valence-variable P2-phase layered oxide material with high sodium content, preparation method and application

An oxide and cation technology, applied in the field of materials, can solve the problems of unstable P2 phase material, poor electrochemical cycle performance, low first-week charging capacity, etc., and achieve great practical value, improve cycle stability, and improve charging capacity. Effect

Inactive Publication Date: 2020-05-15
INST OF PHYSICS - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Layered cathode materials are also a hot topic of research in recent years. Na in the P2 phase x TMO 2 NaTMO with O3 phase 2 It is currently the most researched material [Physical B&C, 1980, 99, 81-85]. The O3 phase has a high sodium content and a high charge capacity in the first week, but its electrochemical cycle performance is poor, and it is sensitive to air and water, so it is difficult to apply. A certain degree of difficulty; P2 phase has good stability in the electrochemical cycle process due to the large space where the sodium ions are located, and the deintercalation of sodium ions is relatively fast, but most P2 phase materials are unstable in the air and due to the relatively low sodium content Its first week charging capacity is generally low
In 2001, Lu et al prepared the P2 phase Na 2 / 3 Ni 1 / 3 mn 2 / 3 o 2 material, and its electrochemical performance was characterized, it has a capacity of 160mAh / g between 2.0-4.5V [Z.H.Lu and J.R.Dahn, J.Electrochem.Soc., 2001, 148, A1225-A1229], but Its electrochemical curve shows multiple platforms, and the cycle stability is extremely poor

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  • Pure cation valence-variable P2-phase layered oxide material with high sodium content, preparation method and application
  • Pure cation valence-variable P2-phase layered oxide material with high sodium content, preparation method and application
  • Pure cation valence-variable P2-phase layered oxide material with high sodium content, preparation method and application

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Embodiment 1

[0059] This embodiment provides a high-sodium content P2 phase layered oxide material with pure cations changed in valence, the general chemical formula is: Na x [Li i Ni j mn k m y ]O 2+β ;

[0060] Among them, Li, Ni, Mn, and M jointly occupy the transition metal ion position in the crystal structure; M is an element for doping and replacing the transition metal position, and M is specifically Cu 2+ , Mg 2+ , Mn 2+ ,Zn 2+ , Al 3+ , B 3+ , Zr 4+ , Ti 4+ One or more of them; x, y, i, j, k, and β are the molar percentages of the corresponding elements; the relationship between x, y, i, j, k, and β satisfies y+i+j +k=1, and x+my+i+2j+4k=2(2+β); where 0.8≤x≤0.85; 0

[0061] The space group of P2-phase layered oxide materials with high sodium content is P6 3 / mmc or P6 3 / mcm, the corresponding structure is P2 phase structure. The XRD collection of illustrative plates in several concrete example...

Embodiment 2

[0066] This example provides a method for preparing a high-sodium-content P2 phase layered oxide material with pure cations changed in price, specifically a solid-phase method, such as figure 2 shown, including:

[0067] Step 201, mixing sodium carbonate with a required stoichiometric amount of 100wt% to 110wt% of sodium, oxides of nickel, manganese, and lithium, and oxides or carbonates with a required stoichiometric amount M to form a precursor;

[0068] M is as described in the above examples, specifically Cu 2+ , Mg 2+ , Mn 2+ ,Zn 2+ , Al 3+ , B 3+ , Zr 4+ , Ti 4+ One or more of them; they are the same in the following embodiments and will not be repeated here.

[0069] Step 202, using a ball milling method to uniformly mix the precursor to obtain a precursor powder;

[0070] Step 203, placing the precursor powder in a muffle furnace, and heat-treating it in an air atmosphere at 800° C. to 1100° C. for 6 to 48 hours;

[0071] Step 204, grinding the heat-treated ...

Embodiment 3

[0074] This example provides a method for preparing a high-sodium content P2 phase layered oxide material with pure cations changed in price, specifically a combustion method, such as image 3 shown, including:

[0075] Step 301, mixing sodium nitrate with a required stoichiometric amount of 100wt% to 110wt% of sodium, nitrates of nickel, manganese, and lithium, and a required stoichiometric M nitrate in proportion to form a precursor;

[0076]Step 302, stirring the precursor with acetylacetone to form a slurry evenly, drying the slurry at 80°C to obtain a precursor powder;

[0077] Step 303, placing the precursor powder in a muffle furnace, and heat-treating it in an air atmosphere at 800° C. to 1100° C. for 6 to 48 hours;

[0078] Step 304, grinding the heat-treated precursor powder to obtain the layered oxide material.

[0079] The preparation method of a high-sodium-content P2-phase layered oxide material provided in this embodiment can be used to prepare the high-sodium...

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Abstract

The invention discloses a pure cation valence-variable P2-phase layered oxide material with high sodium content as well as a preparation method and application thereof. The chemical general formula ofthe material is Nax [LiiNijMnkMy] O2 + beta, and li, Ni, Mn and M jointly occupy the position of transition metal ions in the crystal structure, wherein M is an element for doping and substituting atransition metal site and is one or more of Cu <2+>, Mg <2+>, Mn <2+>, Zn <2+>, Al <3+>, B <3+>, Zr <4+> and Ti <4+>, and x, y, i, j, k and beta are mole percentages of the corresponding elements respectively; the relationship among x, y, i, j, k and beta satisfies y+i+j+k=1, and x +my+i+2j+4k=2 (2 + beta); 0.8<= x<= 0.85; 0<i<= 0.1; 0<j<= 0.4; 0<k <=0.65; -0.05<= beta<=0.05; m is a valence stateof M, and the space group of the layered oxide material is P63 / mmc or P63 / mcm. The material is used as a positive electrode active material of a sodium ion secondary battery, and the charge compensation is completely realized by obtaining and losing electrons by transition metal cations in the charging and discharging process, so that the structural change caused by the participation of anions invalence change is effectively inhibited, and the cycling stability of the material is greatly improved.

Description

technical field [0001] The invention relates to the technical field of materials, in particular to a high-sodium-content P2 phase layered oxide material whose pure cations have changed valence, a preparation method and an application. Background technique [0002] With the development and progress of society, human beings have an increasing demand for energy. However, due to the depletion of traditional fossil energy such as coal, oil, and natural gas, coupled with the increasingly severe problems of urban environmental pollution and greenhouse effect, Its application is gradually restricted in many ways, so the development of sustainable clean energy has always been the direction of attention of all countries. However, in the process of converting wind energy, solar energy, and tidal energy into electrical energy, these renewable energy sources are greatly restricted by natural conditions, and have the characteristics of obvious time discontinuity and spatial distribution, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/505H01M4/525H01M10/054H01M4/131
CPCH01M4/131H01M4/364H01M4/485H01M4/505H01M4/525H01M10/054Y02E60/10
Inventor 胡勇胜赵成龙陈立泉
Owner INST OF PHYSICS - CHINESE ACAD OF SCI
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