Preparation method of nickel-cobalt-aluminum ternary positive electrode material

Abstract

The invention discloses a preparation method of a nickel-cobalt-aluminum ternary positive electrode material. The preparation method comprises the steps as follows: adding a nickel salt solution, a cobalt salt solution, an aluminum salt solution and ammonia water into a sealed container respectively, pressurizing the container, adjusting the pressure to 0.2-0.5MPa, reacting at normal temperature until no precipitation is formed, and treating to obtain a nickel-cobalt-aluminum precursor; mixing the obtained nickel-cobalt-aluminum precursor with lithium carbonate to obtain a mixture, adding ethyl alcohol and glucose into the mixture, sintering after mixing uniformly to obtain the nickel-cobalt-aluminum ternary positive electrode material. According to the invention, the pressure of the reaction system is controlled to be 0.2-0.5 MPa, so that the reaction time is shortened, the preparation of the nickel-cobalt-aluminum ternary material precursor at normal temperature is realized, the energy consumption is reduced, the rate at which aluminum ions precipitate within the pressure range is enabled to be consistent with the rate at which nickel-cobalt ions co-precipitate, nickel-cobalt-aluminum co-precipitation is achieved, and the nickel-cobalt-aluminum ternary positive electrode material with uniform distribution of elements is obtained.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery preparation, and in particular relates to a preparation method of a nickel-cobalt-aluminum ternary positive electrode material. Background technique [0002] Due to the advantages of large specific energy, high working voltage, high safety, and low environmental pollution, lithium-ion batteries have broad application prospects in various portable electronic devices, electric vehicles, and new energy storage. The cathode material is the core component of lithium-ion battery products, which directly affects the final use performance of the battery, and the ratio of cathode materials to battery costs reaches about 40%, so lithium-ion battery cathode materials have always been a research hotspot. [0003] The ternary battery material is one of the new materials for making power lithium batteries. Due to its advantages in resource occupation, cost performance, and safety, it has been regard...

AI Technical Summary

Problems solved by technology

Among them, the nickel-cobalt-aluminum ternary material has the highest capacity. The nickel-cobalt-aluminum ternary system has the best effect due to the doping of aluminum elements and has a long cycle life, but there is a problem: aluminum is an amphoteric substance, and hydrogen is generated when the alkalinity is weak. Alumina, but when the alkalinity is strong, it will form aluminate, which is difficult to control; therefore, most domestic battery manufacturers are still using nickel-cobalt-manganese ternary system materials

This method usually has the following defects: the ternary precursor is mixed unevenly with the lithium source, and it is easy to sinter into agglomerates during high-temperature calcination, and the purity of the obtained ternary positive electrode material is low, which affects the performance and life of the lithium-ion battery.

This patent reacts nickel source, cobalt source, aluminum source compound with precipitant and complexing agent under normal pressure. In order to increase the speed of co-precipitation, the reaction pH value is controlled at 8-12, but the alkalinity is strong and easy to generate aluminate Salt, aluminum is difficult to form a uniform single layered structure with nickel and cobalt precipitation, and it is also difficult to form spherical large particle precipitation; and the nickel-cobalt-aluminum ternary material precursor obtained in this patent is directly mixed with a lithium compound and then calcined, the ternary precursor The mixture of the body and the lithium source is uneven, and it is easy to sinter into a block when calcined at a high temperature. The purity of the obtained ternary cathode material is low, which affects the performance and life of the lithium-ion battery.

Images