Method for preparing lithium-rich positive electrode material through adjustable low temperature combustion method

Abstract

The invention belongs to the technical field of the preparation of positive materials for lithium-ion batteries, and specifically provides a method for preparing a lithium-rich positive electrode material 2x / 3Li2MnO3*(1-x)LiMO2 through an adjustable low temperature combustion method, wherein x is greater than 0 and smaller than 1, and M is Ni, Co and Mn. The method comprises the following steps: dissolving an Ni-Co-Mn metal salt into a solvent according to a stoichiometric proportion, adding a certain amount of a reducing agent and a certain amount of an additive, stirring uniformly, dropwiseadding an appropriate amount of ammonia water to adjust PH so as to obtain a solution A; After heating and evaporating the solution A for a certain period of time, putting the solution A in a heatingfurnace so that the heating furnace is combusted at the temperature of 300 to 700 DEG C to obtain powder B, collecting and grinding the B, putting the powder B in a muffle furnace for combustion for 5to 24 h at the high temperature of 700 to 1100 DEG C, and carrying out ball-milling sieving after cooling to obtain the lithium-rich positive electrode material. The preparation method is simple andquick, various elements in the solution can be mixed in a molecular level, the ultrafine nanoscale material can be prepared, the energy consumption is low, the reaction can be adjusted through parameters, the synthesizing cost of the lithium-rich positive electrode material is greatly reduced, and the rate capability and cycle performance of the lithium-rich positive electrode material are also obviously improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of positive electrode materials for lithium ion batteries, and specifically provides a method for preparing lithium-rich positive electrode materials by an adjustable low-temperature combustion method. Background technique [0002] With the world's energy crisis and environmental protection issues becoming more and more prominent, the background of seeking new energy is the increasing importance of national energy security. In recent years, the market demand for new energy materials such as lithium carbonate has surged, and the new energy revolution will break out in an all-round way and the momentum has already emerged. At present, my country urgently needs to develop lithium-ion batteries with high energy density, high power, long cycle life and high safety. The positive electrode material is the material with the highest cost of lithium-ion batteries, accounting for about 1 / 3 of the cost o...

AI Technical Summary

Problems solved by technology

The positive electrode materials currently used and researched are mainly lithium-containing materials with crystal structures such as layered, spinel, and olivine, mainly LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 o 4 、LiFePO 4 、LiCo 1 / 3 Ni 1 / 3 mn 1 / 3 o 2 And some other series of cathode materials, but each has disadvantages such as poor safety, high price, low energy density, poor cycle performance, etc., which limit its development

With the national requirement for the energy density of lithium-ion batteries to reach 300Wh / Kg, none of the current commercial cathode materials can meet the demand

The new lithium-rich cathode material x Li 2 MnO 3 ·(1- x )LiMO 2 (M=Co, Ni, Mn) The theoretical specific capacity is as high as 350mAh / g, and commercialization is expected to obtain a specific energy of 300Wh / Kg. However, the irreversible capacity loss of the material produced by the traditional co-precipitation method reaches 40~100mAh / g for the first charge and discharge. , due to the erosion of the electrolyte, the poor cycle performance of the material, and the poor discharge performance of the rate, etc.

The current improvement methods mainly include ion doping and surface coating, which undoubtedly increases the cost of battery production

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