Preparation method of lithium ion battery positive material nickel cobalt aluminum

Abstract

The invention discloses a preparation method of lithium ion battery positive material nickel cobalt aluminum. The preparation method comprises the following steps: mixing nickel, cobalt and aluminum salt solutions, mixing a precipitator, a complexing agent and the mixed solution of the nickel cobalt aluminum to obtain a mixed solution, adding the mixed solution into a reaction kettle to carry out co-precipitation reaction, adjusting the pH value of the system to 10 to 11 at the temperature of 40 to 60 DEG C, stirring at the speed of 500 to 1500 turns / minute, carrying out reaction for 10 to 30 hours, filtering, washing and drying to obtain a hydroxide precursor; pre-sintering the precursor at high temperature to obtain a nickel cobalt aluminum oxide, mixing the nickel cobalt aluminum oxide with a lithium source to obtain a mixture, sintering the mixture at high temperature under an oxygen atmosphere, and crushing and sieving to obtain the nickel cobalt aluminum powder. By calculating the pre-sintering loss rate of the precursor, the content of Ni<2+> and the content of Ni<3+> in the nickel cobalt aluminum oxide at different temperatures are analyzed by utilizing XPS, so that the nickel cobalt aluminum oxide with the highest content of Ni<3+> can be obtained, more nickel ions in the secondary sintering process can be promoted to be converted into Ni<3+>, the mixed arrangement of the Li<+> and the Ni<2+> can be reduced, and the electrochemical performance of the material can be improved.

Description

technical field [0001] The invention relates to the fields of energy storage materials and electrochemistry, in particular to a preparation method of nickel-cobalt-aluminum cathode material for lithium ion batteries. Background technique [0002] Since the Japanese SONY company first successfully developed and commercialized lithium-ion batteries in 1991, lithium-ion batteries have attracted more and more attention because of their light weight, small size, high specific energy, small self-discharge, and good cycle performance. With the characteristics of low pollution and no memory effect, it has become one of the most promising green secondary batteries in the 21st century. With the development of electrode materials, battery cathode materials with their own characteristics have emerged one after another, such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, and nickel-cobalt-manganese ternary materials. At present, lithium-i...

AI Technical Summary

Problems solved by technology

Nickel-cobalt-aluminum hydroxide, mainly nickel hydroxide, decomposes above 230°C to form NiO. When the temperature reaches 400°C, part of NiO absorbs air and oxidizes into Ni 2 o 3 , and finally when the temperature is higher than 600℃, the Ni 2 o 3 Reduced NiO with low activity; in addition, if the content of divalent nickel in nickel-cobalt-aluminum oxide is too high, the subsequent sintering process cannot be completely oxidized to trivalent nickel, and the radius of divalent nickel is very close to that of lithium ions, which is prone to mixing. , affecting the electrochemical performance of the material

Therefore, pre-sintering at different temperatures results in different Ni 2+ and Ni 3+ content of the precursor, the electrochemical performance of the final material is different

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