Modified lithium-rich manganese-based positive electrode material and preparation method thereof

Abstract

The invention discloses a modified lithium-rich manganese-based positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials for lithium-ion batteries. The preparation method comprises the steps of fully mixing a lithium-rich manganese-based precursor, a lithium salt and a doped metal compound, and then burning a mixture to prepare the modified lithium-rich manganese-based positive electrode material; and carrying out pretreatment of heat preservation on a lithium-rich manganese-based precursor at 300-650 DEG C for 2-6 hours before mixing. A pretreatment step of the precursor is added to an existing preparation technology of the lithium-rich manganese-based positive electrode material, a crystal structure of the precursor is more complete and an aluminum element is doped, so that the initial coulomb efficiency of the positive electrode material can be significantly improved and is improved by 15-20% in comparison with that of an un-pretreated material; and the rate capability is also greatly improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery cathode materials, in particular to a modified lithium-rich manganese-based cathode material and a preparation method thereof. Background technique [0002] The energy issue is a key issue for a country's sustainable development, and seeking and developing alternative secondary energy is an important national policy of our country at present. Lithium-ion battery is a high-energy battery that has developed rapidly in the past ten years. Due to its advantages of high voltage, high specific energy, good cycle performance, and low environmental pollution, it has become a key direction for the development of new energy industries in various countries. The lithium-ion cathode material is an important part of the lithium-ion battery and a key point in the performance of the lithium-ion battery. [0003] In recent years, low-cost, high-capacity lithium-rich manganese-based cathode materials h...

AI Technical Summary

Problems solved by technology

For example, the patent document whose publication number is CN 101562245 A discloses a method using MnO 2 A method of surface coating the lithium-rich cathode material, which reduces the first irreversible capacity loss of the material and improves the cycle performance of the material at high rates, but the discharge capacity of the modified material is low

The patent document with the publication number CN 102738458 A uses oxides or phosphates of Al, Ce, Mn, Ru, Y, Ni, Co and other elements as the coating layer of lithium-rich manganese-based positive electrode materials. This method improves the first Coulombic efficiency , improve the cycle performance and rate performance, but this modification method reduces the discharge voltage platform of the lithium-rich manganese-based cathode material, resulting in a decrease in the energy density of the lithium-rich cathode material

The patent document with the publication number CN 102694164 A discloses a lithium-rich manganese-based cathode material doped with nitrogen or carbon on the surface. Although this method improves the cycle performance of the lithium-rich manganese-based cathode material, this method does not solve the first Coulombic efficiency. lower question

Images