Monocrystalline nickel-cobalt-lithium manganate cathode material and preparation method and applications thereof

Abstract

The invention provides a monocrystalline nickel-cobalt-lithium manganate cathode material. The chemical formula of the cathode material is Li<z>Ni<x>Co<y>Mn<1-x-y>MO2, wherein 1<=z<=1.05, 0<x<0.8,0<y<0.4, 0<x+y<1, 0<=a<0.1, and M represents a doping element and is one or more of magnesium, aluminum, zinc, titanium, zirconium, niobium, chromium, and rare earth elements. The size of the monocrystalline nickel-cobalt-lithium manganate cathode material is uniform and is in a micrometer level. The compaction density can reach 3.8-3.9 g / cm3. The circulation stability is improved, when the cathode material is used in a battery. The invention also provides a preparation method of the monocrystalline nickel-cobalt-lithium manganate cathode material. The cathode material is prepared by spray drying and a one-time sintering technology, the internal gaps of the cathode material are reduced, the structural defect is avoided, and the service life and safety of the cathode material are both improved.

Description

technical field [0001] The invention relates to the field of battery materials, in particular to a single crystal nickel cobalt lithium manganese oxide positive electrode material and a preparation method and application thereof. Background technique [0002] With the rapid development of the economy and the gradual improvement of people's awareness of environmental protection, people urgently need to find a new energy source to replace the traditional fossil energy. Discharge level, no memory effect, no pollution of heavy metal elements such as lead and cadmium, long cycle life and other advantages, become an ideal choice. Currently commercially available cathode materials for lithium-ion batteries include lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, and lithium nickel cobalt manganese oxide (NCM), etc. NCM is favored by the market due to its higher gram capacity and better safety. [0003] At present, the preparation method of NCM is mostly secon...

AI Technical Summary

Problems solved by technology

[0003] At present, the preparation method of NCM is mostly secondary spherical particles formed by primary grains, that is, nickel source, cobalt source, and manganese source are co-precipitated to prepare the precursor, and then mixed with lithium source, which will be prepared through multiple steps of sintering process in the later stage. There are many internal gaps and obvious structural defects, and the unit pole piece is prone to breakage during the rolling process, resulting in attenuation of battery capacity in the later stage, and the compaction density is greatly limited. At the same time, it also increases the difficulty of processing and limits the improvement of energy density; secondly, The theoretical cycle life of the battery prepared by NCM can reach 1500-2000 times, but due to the large internal pores, it is difficult to cover, and the active material material is in contact with the electrolyte, and will be corroded by HF under high temperature conditions, destroying the interface structure, and causing transition metal The dissolution of Ni, Co, and Mn in the electrolyte, the contact with the electrolyte will lead to an increase in side reactions, a large amount of gas will be generated, the air pressure of the cell will increase, and the battery will expand, causing serious safety hazards

Therefore, there is an urgent need for a new NCM preparation method to overcome the existing shortcomings of NCM, thereby eliminating the safety hazards of NCM in battery applications

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