Preparation method of sharpened monocrystal high-voltage spinel lithium nickel manganese oxide cathode material

Abstract

The invention discloses a preparation method of a sharpened monocrystal high-voltage spinel lithium nickel manganese oxide cathode material. The preparation method comprises the steps that (1) a lithium source, a nickel source, a manganese source, dopants, a fluxing agent and organic acid are mixed evenly; (2) a heating furnace is heated up to 80-300 DEG C and subjected to heat preservation, thena mixed material obtained in the step (1) is put into the heating furnace to be subjected to heat preservation for 0.5-30 h at the temperature, and a low-temperature eutectic mixture is formed; and (3) the low-temperature eutectic mixture obtained in the step (2) is placed into the heating furnace at the preset temperature of 300-700 DEG C to be heated and ignited, then sintered and naturally cooled with the furnace, and thus the sharpened monocrystal high-voltage spinel lithium nickel manganese oxide cathode material is obtained. The preparation method is simple in process, high in efficiencyand low in equipment requirement, the raw material mixing level of a liquid phase combustion method can be reached, raw material splashing in the liquid phase combustion method ignition process is further avoided, and large-scale production is easy to realize.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials, and in particular relates to a preparation method of a sharpened single crystal high-voltage spinel lithium nickel manganese oxide positive electrode material. Background technique [0002] As an energy storage technology that can be repeatedly charged and discharged, lithium-ion batteries have achieved very important and successful applications in the past 20 years, especially as a power source for various mobile electronic devices, which has promoted the development of communication, electronics and other industries. Flourish. However, the energy density and power density of existing lithium-ion batteries are low, and their safety and cycle life have not yet met the requirements of future electric vehicles and energy storage system applications. The energy density and safety of lithium-ion batteries need to be continuously improved. Increasing the output voltage of a single cell is...

AI Technical Summary

Problems solved by technology

The existence of this layer of film hinders the normal deintercalation of lithium ions. As the number of cycles increases, the amount of reversible lithium intercalation will become less and less, resulting in serious capacity fading.

At the same time, the problem of rapid capacity fading during the high-voltage spinel lithium nickel manganese oxide cycle is also due to the electrochemical side reactions between the material and the electrolyte caused by the high voltage, and the breakage, pulverization and detachment of the aggregate particles during the cycle. The exposed fresh internal surface continues to react with the electrolyte, resulting in the formation of other phases, resulting in deterioration of electrical properties

This is mainly because the shape of the current high-voltage spinel lithium nickel manganese oxide is micron secondary spherical particles formed by the agglomeration of primary particles of hundreds of nanometers. The material with the shape of secondary spherical particles has a structure Low mechanical strength and poor firmness. Under high compaction, these secondary spherical particles are easily squeezed and broken, resulting in the exposing of particles inside the material, increasing side reactions and metal ion dissolution, and the electrochemical performance declines; at the same time The primary particle size is too small and there are many structural defects, and the structure is prone to collapse under high-voltage charging and discharging, and it is difficult for the secondary particles to cover these too small particles, so the interface side reaction is difficult to suppress during high-voltage charging and discharging , causing damage to the material structure. In addition, the secondary ball particles are also likely to cause safety problems such as flatulence

[0006] At present, when the industry prepares high-voltage spinel lithium nickel manganese oxide, it is necessary to strictly control the content of fine powder (particles with irregular shape and particle size less than 0.5 micron) in the finished product, because the existence of such fine powder particles will give The use of cathode materials leaves a great potential safety hazard

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