High-crystallinity submicron nickel-cobalt-manganese ternary positive electrode material and preparation method thereof

Abstract

The invention discloses a high-crystallinity submicron nickel-cobalt-manganese ternary positive electrode material and a preparation method thereof. An ethanol solution is used as a base solution, a mixed salt solution and a mixed alkali solution are added into the base solution to prepare the material. The method includes (1) adding the mixed salt solution of nickel, cobalt and manganese, and themixed alkali solution of sodium carbonate and ammonia water into alkali base solution, heating and stirring the mixture to form a suspension, filtering the suspension to obtain a solid, and washing and drying the solid to obtain a ternary precursor; and (2) mixing a lithium salt and the ternary precursor according to a molar ratio that Li:(Ni + Co + Mn) = (1-1.2):1, grinding the mixture, carryingout low-temperature presintering, carrying out heat preservation sintering, and cooling to obtain the high-crystallinity submicron nickel-cobalt-manganese ternary positive electrode material. The preparation method disclosed by the invention has the beneficial effects that an additive or an auxiliary agent is not required to be used, the high-crystalline submicron nickel-cobalt-manganese ternarypositive electrode material with uniformly dispersed particles is obtained, and the cycling stability of the battery is favorably improved.

Description

technical field [0001] The invention relates to a nickel-cobalt-manganese ternary positive electrode material, in particular to a highly crystalline submicron nickel-cobalt-manganese ternary positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high energy density, long cycle life, low self-discharge rate and low environmental pollution, and have been widely used in various portable electronic digital products. In recent years, the rapid rise of the new energy vehicle industry has put forward higher requirements for the performance of lithium-ion batteries. While meeting safety and cycle performance, they must also have high energy density. Among them, the characteristics of cathode materials are the key factors that determine the performance of lithium-ion batteries. Among the developed cathode materials, ternary nickel-cobalt-manganese materials are favored by research...

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Problems solved by technology

However, most of the prepared ternary positive electrode materials are secondary spherical particles formed by the agglomeration of primary particles. The secondary particles are easily broken during the process, which reduces the cycle stability

[0003] In response to the above problems, the researchers prepared a micron-scale single crystal ternary cathode material. In CN106410182A, a method for preparing a high compacted density micron-scale single crystal ternary cathode material published in 2017, by adding additives and in the presence of oxygen and nitrogen The micron-sized single crystal ternary cathode material with high compaction density can be obtained by calcining in the mixed gas of high compaction density, but this process requires the addition of additives and the mixed gas of oxygen and nitrogen, and the obtained material has a large particle size, with a maximum particle size of about 7 μm The size increases the transport distance of lithium ions and electrons in the material to a certain extent, thus affecting the performance

There are also researchers (Kim Y. Lithium nickel cobalt manganese oxide synthesized using alkalichloride flux: morphology and performance as a cathode material for lithiumion batteries[J]. ACS applied materials & interfaces, 2012, 4(5): 2329-2333.) adopted Fluxes such as KCl or NaCl synthesize primary particle ternary cathode materials at high temperatures, but this process requires a flux and sintering at a high temperature of 800-1000°C, which increases the cost

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