Coated lithium-rich manganese base material and preparation method thereof

Abstract

A coated lithium-rich manganese base material and a preparation method thereof relate to the field of lithium ion battery. A coated lithium-rich manganese base material for lithium ion battery anode material comprise chemical molecules of a coated layer Li (NiaMn2-a) O2 and a main phase Li[LixNiyCo1-x-y-z Mnz]O2. The preparation method comprises steps of: (a) preparing soluble nickel, cobalt and manganese salt into a mixed solution, and preparing soluble nickel and manganese salt into a mixed solution; (2) preparing an alkali solution; (3) adding the alkali solution and the mixed solution containing nickel, cobalt and manganese into a reaction kettle, stirring fiercely to obtain a coprecipitation, then pumping the mixed solution containing nickel and manganese salt and the alkali solution, and carrying out a co-precipitation reaction, aging, treatment by a centrifugal machine and drying to obtain a coated precursor M (OH)2 (M=Ni, Co, Mn); and (4) uniformly mixing the precursor with a lithium source, carrying out segment sintering, and then sieving to obtain the lithium-rich manganese base material. The invention provides a lithium ion battery anode material with good cycle performance, and the process has the advantages of simpleness, low production cost, short production cycle and stable product performance.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery cathode material and a preparation method thereof. Background technique [0002] Lithium-ion secondary batteries have been widely used in many fields such as portable electronic devices since their commercialization, and LiCoO 2 Due to the advantages of high voltage and stable electrochemical performance, it occupies an important position in the market, but cobalt resources are relatively scarce and expensive, which limits its application; LiNiO 2 The theoretical capacity is 275mAh / g, the actual capacity is 200mAh / g, and nickel is more abundant than cobalt, and the price is low, but its synthesis conditions are harsh, and non-stoichiometric products are easily generated during the preparation process, among which non-stoometric ratio LiNiO 2 It is mainly reflected in the dislocation of lithium ions and nickel ions and the state of lithium-deficiency and...

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Problems solved by technology

[0002] Lithium-ion secondary batteries have been widely used in many fields such as portable electronic devices since their commercialization, and LiCoO 2 Due to the advantages of high voltage and stable electrochemical performance, it occupies an important position in the market, but cobalt resources are relatively scarce and expensive, which limits its application; LiNiO 2 The theoretical capacity is 275mAh / g, the actual capacity is 200mAh / g, and nickel is more abundant than cobalt, and the price is low, but its synthesis conditions are harsh, and non-stoichiometric products are easily generated during the preparation process, among which non-stoometric ratio LiNiO 2 It is mainly reflected in the dislocation of lithium ions and nickel ions and the state of lithium-deficiency and nickel-rich; with α-NaFeO 2 layered LiMnO 2 The theoretical capacity is 286mAh / g, and the reversible capacity is about 200mAh / g, but the thermodynamic instability makes its preparation difficult, and the layered structure will be transformed into a spinel structure during the cycle, and the capacity decay is very serious; spinel Stone-structured LiMn 2 o 4 It has the characteristics of high working voltage (about 3.9V), low price, and environmental friendliness, but LiMn 2 o 4 The reversible cycle capacity is low (110.120mAh / g), and the rapid loss of capacity at high temperature (55°C) is one of the key factors hindering its commercial application; relatively cheap lithium iron phosphate ion conductivity is poor , the theoretical capacity is 170mAh / g, and the actual discharge specific capacity is only 140mAh / g, the low discharge specific capacity cannot meet the demand for high capacity of 3G electronic products

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