Lithium-rich manganese-based material coated with lithium aluminum titanium phosphate and preparation method of lithium-rich manganese-based material

Abstract

The invention discloses a lithium-rich manganese-based material coated with lithium aluminum titanium phosphate and a preparation method of the lithium-rich manganese-based material. The preparation method comprises the following steps: under the stirring condition, dropwise adding a mixed solution of ammonia water and sodium hydroxide into a mixed solution containing manganese salt, cobalt salt and nickel salt to obtain a hydroxyl precursor; then reacting the hydroxyl precursor with a proper amount of a lithium source to obtain a manganese-based lamellar lithium-rich oxide; adding one or moreof B2O3, BaCl2, PbCl2, CaCl2, KF, LiCl, Na2B4O7, Li2B4O7, LiBO2, Na2BO3, NaCl and KCl as fluxing agents in the sintering process; and finally, crushing the prepared manganese-based lamellar lithium-rich oxide. The lithium-rich manganese-based material coated with the titanium-aluminum phosphate, prepared by the prepared method disclosed by the invention, has the advantages of high specific capacity and excellent cyclic performance, in particular to the magnification performance and the charge-discharge coulomb efficiency of the lithium-rich manganese-based material; and in addition, the morphology of materials can be controlled by adjusting the sintering process and the use amount of the fluxing agents.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium-rich manganese-based material coated with lithium titanium aluminum phosphate and a preparation method thereof. Background technique [0002] With the increasing energy crisis and environmental pollution, new words such as new energy, green, recyclable, and energy storage have increasingly become hot spots in social development; although lead-acid batteries and nickel-metal hydride batteries can alleviate this to a certain extent However, due to its unfriendly environment, low voltage platform, and energy density, it is always difficult to play a constructive role in the issue of green development; solar energy, wind energy, tidal energy and other energy sources are important to human beings. A rich and truly green energy source, but due to its indirect unsustainability and other issues, it is difficult to solve the energy problems faced by mankind at this...

AI Technical Summary

Problems solved by technology

[0005] However, the discharge capacity of common commercial cathode materials is generally lower than 200mAh / g, such as lithium cobaltate, lithium iron phosphate, various nickel-cobalt-manganese ternary materials, etc., which are difficult to meet the development requirements of electric vehicles or hybrid electric vehicles; Lithium-rich layered cathode materials have a high specific capacity, with a discharge specific capacity of 240mAh / g at a discharge platform of 2.0V-4.8V; therefore, lithium-rich materials are considered to be one of the most promising cathode materials; however, Lithium-rich layered materials still have three major defects to be overcome in the process of commercialization: 1. The Coulombic efficiency of the first charge and discharge is relatively low; this is mainly because when the discharge voltage exceeds 4.5V, Li 2 MnO 3 Decomposition occurs to generate Li 2 O, resulting in Li 2 O loss and electrode oxidation increase the irreversible capacity of the first charge and discharge; and, due to the low Coulomb efficiency, a large amount of lithium metal is deposited on the carbon negative electrode, which will also cause serious safety problems; 2. Poor cycle stability, voltage platform and discharge The capacity decay is serious; this is mainly due to the instability of the interface between the electrode and the electrolyte under high voltage, especially during the first cycle, the release of oxygen from the lattice will lead to the generation of microcracks on the surface of the positive electrode material, And it is accompanied by lattice distortion; moreover, in the long-term cycle process, cation mixing occurs in the transition metal layer, resulting in the gradual transformation of salt rock phase to spinel phase; recent studies have found that its voltage platform decays and transitions Metal atoms are bound in the tetrahedral gap has a great relationship; using element doping found that when the radius of the doped element is larger, the voltage plateau attenuation is significantly improved; this is because the transition metal atoms with a larger radius enter the tetrahedral The energy barrier that needs to be overcome in the bulk gap is relatively high, so that there are fewer transition metal atoms bound in the tetrahedral gap; 3. Li in lithium-rich materials 2 MnO 3 The electronic conductivity of the component is poor, so the rate capability of the material is poor

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