Nano-modified polyanionic cathode active material, preparation method thereof, and lithium ion secondary battery

A cathode active material, polyanion technology, applied in the field of high-performance lithium-ion secondary batteries, can solve the problems affecting the physical and chemical properties of materials such as tap density, specific capacity, easy growth of polyanion materials, and poor discharge performance at high currents. , to achieve the effect of easy preparation and application, high cycle stability, and improved electrical conductivity

Active Publication Date: 2012-01-11
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the disadvantage of polyanionic positive electrode materials is that the electrical conductivity is relatively low, and the high-current discharge performance of the material is poor. Nanoparticles are an effective way to improve electrical conductivity.
However, during the preparation process, especially during high-temperature heat treatment, due to the high heat treatment temperature, the polyanion material is easy to grow, which in turn affects the conductivity of the material.
[0005] At present, the methods of nano-forming polyanion cathode materials include grinding and pulverizing, adding surfactants, and coating with carbon materials. These methods are either costly or affect the physical and chemical properties of materials such as tap density and specific capacity.

Method used

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  • Nano-modified polyanionic cathode active material, preparation method thereof, and lithium ion secondary battery
  • Nano-modified polyanionic cathode active material, preparation method thereof, and lithium ion secondary battery
  • Nano-modified polyanionic cathode active material, preparation method thereof, and lithium ion secondary battery

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preparation example Construction

[0045] The preparation method of the positive electrode is to blend the positive electrode active material, the conductive agent and the binder in the solvent, coat the current collector on the current collector after mixing evenly, and form the positive electrode sheet after drying. The positive active material used here is nano-modified polyanion and its composite material. The conductive agent can be conductive carbon material, such as conductive carbon black, Super P, and the current collector is aluminum foil.

[0046] The preparation method of the negative electrode is that the negative electrode active material and the binder are blended in a solvent, mixed evenly, coated on the current collector, and dried to form a negative electrode sheet. Negative electrode active material active material can be metal lithium; Carbon material, as graphite, pyrolytic carbon, coke, carbon fiber and high-temperature sintered organic polymer compound etc.; , Al, Ga, In, Si, Sn, Pb, Sb,...

Embodiment 1

[0049] The first step is to disperse ferrous oxalate, ferric oxide and lithium dihydrogen phosphate in a molar ratio of 0.9:0.1:1 in a certain amount of water, and add 20% sucrose of the above-mentioned solid mass, the solid content is 20%, and then Then ball milled in a ball mill at a speed of 500 rpm for 20 hours, and the mass ratio of solids to balls was 1:10. The mixture was spray-dried to obtain a composite electrode material precursor.

[0050] In the second step, the precursor powder is pretreated at 350°C for 1-4 hours under argon protection, then heat-treated at 400-450°C for 1-10 hours, and then heat-treated at 450-550°C for 1-10 hours, Finally, heat treatment at 550-900° C. for 1-10 hours to obtain nanometer lithium iron phosphate polyanion material.

[0051] The third step is to mix the nano-lithium iron phosphate polyanion positive electrode active material with the conductive agent Super P and the binder polyvinylidene fluoride in nitrogen methyl pyrrolidone in ...

Embodiment 2

[0053] The first step is to disperse ferrous oxalate, iron oxide and lithium dihydrogen phosphate in a molar ratio of 0.5:0.5:1.0 in a certain amount of water with a solid content of 20%, and then put them in a ball mill at a speed of 500 rpm After ball milling for 20 hours, the mass ratio of solids to balls was 1:10. The mixture was spray-dried to obtain a composite electrode material precursor.

[0054] The second step is the same as the second step of Example 1, and a doped nano polyanion lithium iron phosphate electrode material is prepared.

[0055] Subsequent steps are the same as the third step in Example 1.

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Abstract

The invention relates to a nano-modified polyanionic cathode active material, a preparation method and a cathode-active-material-based lithium ion secondary battery. The cathode active material is the polyanionic cathode active material with high nanocrystallization degree obtained by uniformly mixing various metal ion source-containing precursors, polyanion-containing precursors and a lithium-containing precursor in a certain ratio in a solid phase or liquid phase mode, drying the mixture, and controlling the crystal growth by means of heat treatment; the molecular formula of the polyanionic material is LimMnXpOq, wherein m, n, p and q are any positive integers less than 10; M is one or a plurality of metals; and X is one or more of P, Si, S, As, Mo, W and the like. The preparation method of the invention is simple and convenient to operate, and is easy for large-scale production. The cathode-active-material-based lithium ion secondary battery has the advantages of high volume, high multiplying performance, high cyclical stability and the like.

Description

technical field [0001] The invention belongs to the technical field of energy storage materials, and in particular relates to a positive electrode active material, a related preparation method and a high-performance lithium-ion secondary battery. Background technique [0002] One of the key technologies related to electric vehicles and electric tools is energy storage technology. At present, the energy storage technology with commercial value and excellent comprehensive performance is power lithium battery technology. Lithium-ion batteries have high working voltage, high specific energy, long cycle life, light weight, less self-discharge, no memory effect, and high performance-price ratio. Advantages, has become the main choice of rechargeable power supply in high-power electric vehicles, artificial satellites, aerospace and other fields. Therefore, lithium-ion batteries and related materials have become one of the research hotspots of researchers all over the world. Among...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/485H01M4/38H01M4/1397H01M4/131H01M4/136H01M10/0525H01M10/0566
CPCY02E60/122Y02E60/10
Inventor 刘兆平唐长林张建刚马池周旭峰
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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