A kind of preparation method of manganese lithium silicate composite cathode material doped with praseodymium cobalt phosphorus

Abstract

The invention relates to a preparation method of a praseodymium cobalt phosphorous-doped lithium manganese silicate composite positive material. The chemical formula of the praseodymium cobalt phosphorous-doped lithium manganese silicate is as follows: LiMn<1-x-y>CoxPrySi<1-z>PzO4, wherein x is 0.2 to 0.25, y is 0.01 to 0.02, and z is 0.22 to 0.34. The method comprises the following steps of (1) preparing a praseodymium cobalt phosphorous-doped lithium manganese silicate precursor; (2) thermally treating the praseodymium cobalt phosphorous-doped lithium manganese silicate precursor and crushing the praseodymium cobalt phosphorous-doped lithium manganese silicate precursor to obtain the precursor powder, dispersing carbon black and active carbon into acetone to form conductive carbon dispersion liquid, mixing the precursor powder and the conductive carbon dispersion liquid, and ball milling the mixture; and (3) drying, placing the mixture with 1:1 (mol)CO / CO2 into a purging intermittent converter, sintering the mixture, and grinding and filtering the mixture to obtain a product. According to the prepared praseodymium cobalt phosphorous-doped lithium manganese silicate composite positive material, the rare earth element Pr and the metal element Co are doped in the lithium manganese silicate so as to modify Mn, and partial Si elements are substituted by the P element, so that the electron conductivity and substance activity can be improved.

Description

Technical field [0001] The invention relates to a preparation method of a praseodymium cobalt phosphorus doped manganese lithium silicate composite cathode material. Background technique [0002] With the rapid development of the battery industry, various types of batteries have emerged in order to solve many problems such as battery life, energy density, self-discharge, or quality. At present, due to the advantages of high energy density, long service life, light weight, and small self-discharge, lithium batteries have become the preferred power source for portable devices such as communication equipment and notebook computers, and have also begun to be applied to electric vehicles, national defense, etc. In large-scale equipment. [0003] As a new generation of lithium-ion battery cathode materials, polyanionic cathode materials have attracted widespread attention, especially the silicate cathode materials that are considered the most promising have many advantages: ①In theory, ...

AI Technical Summary

Problems solved by technology

In a lithium ion secondary battery using such a polyanionic compound with low electron conductivity as a positive electrode active material, a sufficient capacity cannot be obtained with respect to the theoretical capacity. Compared with the case, there is a problem that the rate characteristic becomes lower

Even in the case of compounding polyanionic compounds and carbon, since the particle size of carbon is larger than that of particles composed of polyanionic compounds, the particles composed of polyanionic compounds cannot be sufficiently covered by carbon, and cannot Sufficiently secure the contact area between particles made of polyanionic compounds and carbon

Therefore, there is a problem that the electron conductivity of the polyanion compound cannot be sufficiently improved, and then sufficient capacity and rate characteristics cannot be obtained in a lithium ion secondary battery using the polyanion compound as a positive electrode active material.