Method for producing lithium battery anode material doped with multi-elements by secondary depositing method

Abstract

Production of lithium-battery positive material doped by multi-elements by secondary depositing method is carried out by doping and coating for at least two elements from Al, Mg, Ti and Cr in Li(CoxNiyMnz) by co-deposition, forming into intermediate A, forming intermediate B coated by Co(OH)2 on intermediate A by co-deposition, secondary sintering at a certain temperature to form into product Li(CoxNiyMnzAlaMgbTicCrd)02-kLiCo02. Its advantages include low cost, high charge capacity, excellent safety performance and stability.

Description

technical field [0001] The invention relates to a preparation method of a lithium battery positive electrode material, and further refers to a method for preparing a lithium battery positive electrode material doped with various elements by chemical deposition. Background technique [0002] At present, the commercial lithium-ion battery cathode material is mainly layered LiCoO 2 . But it has several problems: (1) The high price due to the lack of cobalt resources forces people to look for alternative materials with low price and good performance; (2) LiCoO 2 The development limitation of material energy density (there is no major breakthrough in several years after the development to 140mAh / g) makes it more and more difficult to meet the needs of the ever-changing electronic industry; (3) poor safety performance and high temperature performance, not suitable for manufacturing Make high-capacity batteries. [0003] Therefore, the development of some positive electrode mate...

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Problems solved by technology

But it has several problems: (1) The high price due to the lack of cobalt resources forces people to look for alternative materials with low price and good performance; (2) LiCoO 2 The development limitation of material energy density (there is no major breakthrough in several years after the development to 140mAh / g) makes it more and more difficult to meet the needs of the ever-changing electronic industry; (3) poor safety performance and high temperature performance, not suitable for manufacturing Make a large capacity battery

At present, the research at home and abroad mainly focuses on LiCoO 2 Alternative products Li(Co x Ni y mn z )O 2 , where: 02 , LiNiO 2 and LiMnO 2 It has the advantages of low cost, high charge and discharge capacity, and good safety performance. However, the compatibility of the material with the electrolyte is poor, which leads to the deterioration of the cycle performance of the battery. Under the C / 5 charge and discharge rate, the 200 cycle capacity drop by more than 20%. At the same time, the pH of this type of product is high, and contact with air can easily lead to the precipitation of lithium, and the material performance deteriorates sharply.

Although studies have shown that a single doped Ti, Al, Cr, Mg or TiO 2 , MgO 2 and LiCoO 2 Coating treatment can improve to a certain extent, but because of the physical coating between particles, and a single doping cannot produce a synergistic effect, it still cannot fundamentally solve the problem

In addition, the discharge platform of this type of product above 3.6V is low, accounting for only 40-50% of the total capacity

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