Liquid-phase synthesis of anode material for lithium ion secondary battery

Abstract

The method includes following steps: 1) prepares mixing aqueous solution containing cobalt or manganic compounds, lithium compounds and polymer monomer; the mole number ratio of lithium to cobalt is (0.9-1.1):1; the mole number ratio of lithium to manganese is (1~1.1): 2; the volumetric ratio of water to polymer monomer in mixing aqueous solution is (0.2-5): 1; the structure formula of polymer monomer is alkene compound; 2) the mixing aqueous solution is put into the condition under the Y-ray irradiation; Y-ray is used to lead polymerization of polymer monomer in solution and to get macromolecule gel; 3) the gel is processed through drying, thermal decomposition and sintering to form the anode material.

Description

technical field [0001] The invention relates to a lithium ion battery preparation technology, in particular to a method for preparing a lithium ion battery cathode material. Background technique [0002] Lithium-ion batteries were developed and commercialized by Japan's SONY company in 1990. Its appearance can be regarded as a leap in the history of secondary batteries. With the rapid development of the information industry, the consumer market for portable communication devices and laptop computers is getting bigger and bigger. Lithium-ion batteries are a new generation of power sources. Compared with other batteries, lithium-ion batteries have the advantage of high open circuit voltage (commercially available batteries) Most of them are 3.6V, while the open circuit voltage of nickel-hydrogen and nickel-cadmium secondary batteries is 1.2V), large specific capacity (2.5 times that of nickel-cadmium secondary batteries, 1.5 times that of nickel-hydrogen secondary batteries), ...

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Problems solved by technology

[0004] In the prior art, the synthesis of positive electrode materials mostly adopts the solid-state reaction method, that is, the oxide or carbonate of lithium and cobalt or manganese is used for long-term calcination at a high temperature of 800-900 ° C. The advantage of this method is that the process is simple , but there are also obvious disadvantages: the composition of the synthetic material is uneven, the particles are large and the distribution range is wide, the calcination temperature is high and the time is long. Generally speaking, the positive electrode material must have a good crystal structure, uniform composition, submicron size particles diameter, narrow particle size distribution, large specific surface, etc. to obtain high electrochemical performance, it is obvious that the solid-phase method is difficult to meet these conditions; Chinese patent application 99113860.0 uses polyvinyl alcohol or polyethylene glycol aqueous solution as a solvent, after heating , Concentrate to form a gel, and obtain the required powder after calcination. This method has the advantages of high product purity and uniform chemical composition, but it needs a long time of heating and stirring the concentrated solution, which is time-consuming and consumes a lot of energy; Chinese patent application 02123112.5 A citrate gel method is proposed to prepare lithium battery cathode materials. This method has the advantages of low synthesis temperature and uniform particle size, but it is necessary to strictly control the pH value of the solution during the preparation process. If the control is not good, it will Form precipitation, and can not obtain gel; It is similar with it, proposes to utilize nano-reactor to prepare the new technology of nanometer lithium cobalt oxide in the Chinese patent application 0112937.6, but also there is need to adjust the problem of pH value and reaction slower, so in practice The process of application is subject to certain restrictions; Chinese patent application 97112128.1 also proposes a preparation scheme utilizing hydrothermal method. The preparation process of this scheme is simple, but the reaction needs 5 days. Obviously, the reaction time is too long, and there are also production problems. Disadvantages of low rate

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