Preparation of oxidized inserting layer of laminated lithium manganate as lithium ion battery anode

Abstract

In the method, under protection of nitrogen gas, manganese salt and strong alkali are dissolved in boiled deionisation respectively to prepare forebody material of manganous hydroxide in laminate structure. According to certain proportion, adding intercalation object of lithium compound to suspending liquid of laminate forebody and carrying out intercalation prepares laminate lithium manganate under synergetic effect of oxidant. Chemical constitution formula of lithium manganate is LixMnO2 (0.8 is less than or equal to x is less than or equal to 1.0). Characters of produced lithium manganate are orthorhombic crystal system, Pmnm spatial symmetry, high purity, no impurity phases, and controllable even grain size. Laminate lithium manganate as material of positive pole provides high specific capacity and good cycle performance. Features of the invention are simple technique, cheap material and easy to realize commercial manufacture.

Description

technical field [0001] The invention relates to an oxidation-intercalation preparation method of layered lithium manganese oxide, which is a cathode material of lithium ion batteries, and belongs to the technical field of preparation of lithium ion battery materials. Background technique [0002] In lithium-ion batteries, electrode materials are an important part of them, especially the positive electrode materials are used in a large amount and are expensive, which is a key factor affecting the performance and production cost of lithium-ion batteries. [0003] At present, commercial lithium-ion batteries mostly use layered lithium cobalt oxide LiCoO 2 as anode material. Lithium cobalt oxide has excellent electrochemical performance. However, cobalt is expensive and pollutes the environment, which greatly restricts the popularization of lithium-ion batteries using lithium cobaltate as the positive electrode material, especially in the development of large-capacity electric...

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Problems solved by technology

The product prepared by the hydrothermal synthesis reaction method has excellent electrochemical properties, but this method requires expensive special equipment—high pressure reactor, and it is not easy to realize large-scale industrial production due to the limitation of the volume of the reaction vessel.

[0007] Ion exchange reaction method: in literature (4) Nature, 1996,381:499, people such as Robert Armstrong A will Na 2 CO 3 and Mn 2 o 3 Mix according to stoichiometric ratio, and react in solid state at 700-730°C for 18-72 hours under argon atmosphere to obtain α-NaMnO 2 , and then a certain amount of α-NaMnO 2 Add it to n-hexanol containing excess LiCl or LiBr, heat it under reflux at 145-150°C for 6-8 hours, cool to room temperature, filter, rinse with n-hexanol and ethanol, and dry to obtain monoclinic LiMnO 2 , in the voltage range of 3.4 ~ 4.3V (vs. Li), the current density of 10μA cm -2 Under the test conditions, the initial charging capacity is 270mAh·g -1 , when the current density is 0.5mA·cm -2 , the first charge capacity is close to 200mAh·g -1 , but the reversible capacity (i.e. discharge capacity) of the material is low. In addition, the layered precursor in the ion exchange reaction method generally needs to be prepared by a high-temperature solid-state reaction method. The ion exchange process requires some expensive raw materials, and the production process is complicated. Harsh reaction conditions are not conducive to large-scale production

[0008] Melt impregnation method: In the literature (5) Journal of Power Sources, 1995, 54: 483, YoshiioM et al. first made lithium salt (LiNO 3 or LiI) is heated to the melting point, so that the molten lithium salt is immersed in the MnO 2 In the hole, and then heated to the predetermined reaction temperature, layered Li belonging to the orthorhombic system can be obtained x MnO 2 , but the degree of lithiation of the product obtained by this method is not high (x<0.5), which is not conducive to obtaining high specific capacity electrode materials

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