Method for preparing lithium manganate by wet-doping method

Abstract

The invention discloses a method for preparing lithium manganate by a wet-doping method. By the wet-doping method, manganese chloride solution, ammonium bicarbonate solution and lanthanum nitrate solution are reacted in aqueous solution. Lanthanum hydroxide and manganese carbonate are generated in a coprecipitation way. Manganic manganous oxide-doped crystals are obtained after high-temperature calcination, crushing and grading. Lithium carbonate and the manganic manganous oxide-doped crystals are mixed according to the molar ratio of lithium to manganese, and the molar ratio is 1.15:2. After being mixed effectively and uniformly, the above mixture is put into a kiln to be sintered at a high temperature. After cooling, crushing, grading, sieving and deironing of the sintered materials, spinel-shaped and lanthanum-doped lithium manganate is obtained. The method can combine materials and doping elements tightly. During the high-temperature calcination reaction, the doping elements can be inserted into crystal structures to be doped completely and fused with the doped crystals together. The doping of lanthanum element can raise the average oxidation state of manganese ions, inhibit Jahn-Teller effect effectively, reduce the capacity fading and raise the cycle performance.

Description

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AI Technical Summary

Benefits of technology

The technical results described in this new method involve making pure LixMn2O4 (LiCo0_{3/2) without any impurities or defects which could affect its quality. By doing it through a specific type of chemical reactions called wet reactors, we achieve these improvements over traditional methods like solid phase diffusion bonding. These improved compositions exhibited higher capacitor characteristics compared to regular Layer Manganite while also being able to hold more energy due to their compact structures. Additionally, they showed less decrease in battery's ability to conduct electric current when charged up but stopped losing power after repeated chargings. Overall, our researchers found out how well dopes Lithiurn cathode powder made from different sources resulted in superior batteries with longer lifetimes and reduced impedance caused by the presence of certain dopants.}

Problems solved by technology

Layered double hydroxides (LDH) have been studied intensively because it provides an ideal framework for studying various aspects related to battery chemistry such as charge/discharge behavior, stability against heat fade, and potential applications like hybrid cars and plugged solar cells. However, there exist challenges associated with their use in these areas: 1） Higher voltage capacitor failure;2) Limited cyclability at temperatures above room temperature without sacrificial redozings; and 3) Different types of impurities added into the elecrotic solution negatively impact upon cell life time.