Preparation method and application of high-capacity high-temperature-resistant lithium manganate

Abstract

The invention discloses a preparation method and application of high-capacity high-temperature-resistant lithium manganate. The preparation method comprises a first step of enabling manganese sulfate, ammonium persulfate and aluminum sulfate to undergo a hydrothermal reaction and then be heated in air, and obtaining aluminum-doped nanometer gamma-manganese dioxide; a second step of enabling products in the first step and lithium carbonate to be dispersed in an organic solvent and undergo ball-milling crushing and drying, performing primary sintering in the presence of oxygen, and obtaining an aluminum-doped lithium manganate precursor; a third step of mixing aluminum nitrate, the aluminum-doped lithium manganate precursor and water to obtain suspension liquid, adding phosphate and polymeric dispersants in the suspension liquid, evaporating the solvent after mixing, performing secondary sintering in the presence of oxygen, and obtaining the product. The invention further discloses application of the high-capacity high-temperature-resistant lithium manganate in batteries. The product has the advantages of high charge-discharge capacity and small in circulation attenuation. The initial charge gram volume is 137.7mAh / g, and the charge gram volume is kept at 121.1 mAh / g after circulation for 30 circles. The preparation process is free of pollution, and the preparation method is high in yield and suitable for industrialized production.

Description

technical field [0001] The invention belongs to the field of nanometer materials, and the invention relates to a preparation method and application of high-capacity and high-temperature-resistant lithium manganate. Background technique [0002] As the current main driving force, chemical petroleum fuels have brought serious problems such as exhaustion of energy resources and increasing environmental pollution. The use of power sources for new energy vehicles (EV, HEV, PHEV) is becoming a power source that may replace petroleum resources. Lithium-ion batteries have high energy density and are receiving more and more attention. There are many kinds of cathode materials for lithium-ion batteries. As a cathode material, lithium manganate has the advantages of simple preparation, low cost, high voltage, high compaction density, and high volume capacity. It has great application potential in power batteries and energy storage batteries. and advantages, but the high-temperature c...

AI Technical Summary

Problems solved by technology

[0009] Divalent manganese will precipitate on the negative electrode, which will reduce the content of trivalent manganese in the positive electrode and reduce its capacity, and on the other hand manganese oxides will deposit on the negative electrode Cause the negative electrode active material to fall off, greatly reducing the cycle performance of the battery (Numerical Simulation of the Effect of the Dissolution of LiMn2O4 Particles on Li-Ion Battery Performance, Jonghyun Park, Jeong Hun Seo, Gregory Plett, Wei Lu and Ann Marie Sastry, Electrochemical and Solid-State Letters, 2011, 14(2), A14 - A18)

[0011](3) Oxygen deficiency: Oxygen deficiency in the spinel structure will also weaken the bond energy between metal atoms and oxygen atoms, resulting in increased dissolution of manganese

Doping modification such as cation doping Li, Mg, Ni, Al, Co, Cr, Cu, La, Fe, Ce, V, Ti, Sn, Zn and other elements to replace Mn3+ Improve the stability of lithium manganese oxide structure, improve the cycle performance of the material, but at the same time reduce its specific capacity

For example, the aluminum-manganese oxide used by Qingdao Xinzheng Lithium Industry; and the introduction of doping elements such as Bi, Cr, etc. will also cause environmental pollution

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