Method for improving electrochemical performance of high-nickel ternary positive electrode material by magnesium fluoride/sodium synergic modification

Abstract

The invention discloses a method for improving electrochemical performance of a high-nickel ternary positive electrode material by magnesium fluoride / sodium synergic modification. The method comprisesthe steps of (1) fully grinding a precursor, a lithium source and a sodium source to obtain a mixture, performing two-segment high-temperature calcination on the mixture in a tubular furnace under anoxygen atmosphere, and cooling with the furnace to a room temperature, thereby obtaining Li<0.9>Na<0.1>Ni<0.8>Co<0.1>Mn<0.1>O2; and (2) adding Li<0.9>Na<0.1>Ni<0.8>Co<0.1>Mn<0.1>O2 after magnesium nitrate and ammonium fluoride are mixed in absolute ethyl alcohol, performing stirring and drying, adding a few amount of absolute ethyl alcohol, performing heat preservation in the tubular furnace under an argon atmosphere for a certain time after grinding, thereby obtaining a MgF2 / Li<0.9>Na<0.1>Ni<0.8>Co<0.1>Mn<0.1>O2 composite material. The method is simple in process and low in cost, and the sodium ion-doped and magnesium fluoride-coated MgF2 / Li<0.9>Na<0.1>Ni<0.8>Co<0.1>Mn<0.1>O2 composite material having favorable electrochemical performance such as large rate performance and cycle propertyis prepared.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a method for improving the electrochemical performance of high-nickel ternary positive electrode materials through magnesium fluoride / sodium synergistic modification. Background technique [0002] Energy and the environment have always been the main problems facing our country's modern development. One of the important means to solve this problem is to find sustainable new energy, gradually replace the existing traditional energy, and meet everyone's needs. The research and development of new energy sources has become a common topic of major research institutes and major enterprises in various countries. New energy sources should have the characteristics of high efficiency, easy portability, good safety performance, and environmental protection. Due to the advantages of small size, high specific energy, high working voltage, and long service life, lithium-ion batteries have b...

AI Technical Summary

Problems solved by technology

However, there are still many problems in high-nickel materials. (1) More Ni content will increase the pH value of the material, which is easy to absorb water and CO 2 , not easy to store; (2) Ni 2+ The amount is more, the cation mixing is more serious, and the first Coulombic efficiency decreases

(3) The reduction of Co content makes the structural stability of the material worse, and the cycle performance is not good; (4) LiNi 0.8 co 0.1 mn 0.1 o 2 The preparation is more difficult, because part of the Ni 2+ To be oxidized to Ni 3+ There is a large potential barrier and it is difficult to be completely oxidized, so in the high temperature sintering stage, it must be synthesized under an oxygen atmosphere

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