High-nickel positive active material of surface-modified lithium ion battery and preparation method of positive active material

Abstract

The invention discloses a high-nickel positive active material of a surface-modified lithium ion battery. A matrix substance is the high-nickel positive active material LiNixCoyMzO2, the surface of the matrix substance is uniformly coated by a lithium-ion conductor compound which comprises at least one of LiAlO2, Li4Ti5O2 and Li2ZrO3; the content of the total impurity lithium in the positive active material is below 0.085%. The invention also discloses a preparation method of the positive active material. The preparation method comprises the following steps of: firstly mixing the matrix substance with an organic solution containing aluminum, an organic solution containing titanium or an organic suspension liquid containing aluminum / titanium / zirconium, drying, calcining the dried mixture, finally generating the lithium-ion conductor compound on the surface of the matrix substance, namely the high-nickel positive active material of the surface-modified lithium ion battery. The high-nickel positive active material disclosed by the invention has the advantages that the content of alkali substances is obviously reduced, the processing performance of the material is improved, and the electrochemical stability is improved.

Description

technical field [0001] The invention relates to a battery cathode material and a preparation method thereof, in particular to a lithium ion battery cathode active material and a preparation method thereof. Background technique [0002] At present, lithium-ion batteries have been widely used in various mobile electronic products, power tools and energy storage systems. In order to adapt to the development of these devices, there is an increasing demand for lithium-ion batteries with high energy density, high power, long life and low cost. Lithium-ion cathode materials are the key materials that affect battery performance and cost. However, the current commercial applications of lithium cobalt oxide, lithium manganese oxide, and lithium iron phosphate are difficult to make breakthroughs in specific capacity, while doped lithium nickel oxide cathode materials The material has attracted attention because of its high capacity and low cost, and is expected to become the market-le...

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Problems solved by technology

The coatings used, such as MgO (see Chinese Patent Document No. CN1770514A), AlF3 (see B.-C. Park, H.-B. Kim, H.J. Bang, J. Prakash, Y.-K. Sun, Industrial & Engineering Chemistry Research 47 (2008): 3876-3882), AlPO4 (see B. Kim, C. Kim, T.-G. Kim, D. Ahn, B. Park, Journal of The Electrochemical Society153(2006): A1773-A1777 and No. CN1416189A Chinese Patent Literature) and conductive glass (referring to CN1797822A and CN1773763A No. Chinese Patent Literature), etc., although the electrical conductivity of the material can be improved to a certain extent Chemical stability, but these coatings cannot react with the alkaline substance of the high-nickel positive electrode active material and cannot reduce its alkalinity

In addition, it is also reported that other aluminum, titanium and zirconium compounds are added to the positive electrode material (see CN1773763A, CN1731605A, CN1416189A), but the existing process operation is not designed for "reducing the alkalinity of high nickel positive electrode active materials", so Also fail to solve the above-mentioned problems that the high-nickel cathode material of lithium-ion battery exists

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