Method for preparing modified lithium nickel manganese oxide which is anode material of lithium ion battery

Abstract

The invention discloses a method for preparing modified lithium nickel manganese oxide which is the anode material of a lithium ion battery. The method comprises the following steps: mixing a manganese salt material and a nickel salt material, and preparing a nickel manganese precursor through a sol-gel method; mixing the nickel manganese precursor and the nickel salt by using a three-dimensional oblique type mixing machine; presintering and high temperature sintering, and doping F- or F- and metal cations, then adding a metallic oxide and performing wet coating; and finally, acquiring a lithium nickel manganese oxide finished product by low temperature sintering, fluid energy milling and grading. The method provided by the invention uses an ion doping modification technology to improve the cycle performance and high temperature stability of the lithium nickel manganese oxide, and uses a wet coating technology to improve the high pressure cycle performance and high temperature stability of the lithium nickel manganese oxide.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a preparation method of modified lithium nickel manganese oxide. Background technique [0002] Lithium-ion power battery is currently recognized as the most potential vehicle battery at home and abroad. It is mainly composed of positive electrode materials, negative electrode materials, separators, electrolytes, etc. Among them, positive electrode materials are an important part of lithium-ion batteries and also determine the quality of lithium-ion batteries. Therefore, in terms of resources, environmental protection and safety performance, finding the ideal electrode active material for lithium-ion batteries is still the primary problem to be solved by international energy materials workers. [0003] Lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 o 4 ) and lithium iron phosphate (LiFePO 4 ); Lithium cobaltate is currently widely used as a positive elect...

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Problems solved by technology

[0003] Lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 o 4 ) and lithium iron phosphate (LiFePO 4 ); Lithium cobaltate is currently widely used as a positive electrode material for small lithium-ion batteries, but because cobalt is toxic, resource reserves are limited and expensive, and batteries assembled with lithium cobaltate materials as positive electrode materials have poor safety and thermal stability. Oxygen will be generated at high temperature, which cannot meet the technical requirements of power batteries; although lithium manganate is cheap, environmentally friendly, safe, and has good rate performance and safety performance, its theoretical capacity is not high, and its cycle performance, thermal stability and high temperature performance are relatively low. Poor, the biggest problem in application is poor cycle performance, especially at high temperature, the trivalent manganese ions in the material and the divalent manganese ions formed on the particle surface during high-rate discharge make the material dissolve significantly in the electrolyte , eventually destroying the structure of lithium manganate and reducing the cycle performance of the material; the lithium manganate materials that can be used in the market are all obtained through modification measures. On the one hand, such modification measures require high-standard Synthetic equipment, on the other hand, also needs to be at the cost of reducing the reversible capacity of the material, so these materials have been difficult to replace lithium cobalt oxide; lithium iron phosphate is a new lithium-ion battery cathode material that has attracted widespread attention in recent years. It has superior safety performance and good recycling performance, and has a good application prospect, but the material has a small tap density and a low voltage platform, so the specific energy after being made into a battery is low, making it unsuitable for high-voltage applications. Where energy density is required

[0004] As far as the current technology is concerned, the voltage of these commercially available cathode materials relative to the graphite anode is below 4V, which limits the power of the battery. Therefore, the development of high voltage, high capacity, safety and good cycle performance Ni-doped Miscellaneous LiMn 2 o 4 with 5V grade LiNi 0.5 mn 1.5 o 4 , which has important practical significance for the development of high-power lithium-ion power batteries for electric vehicles

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