Doped monocrystal multi-component material for lithium ion batteries and preparation method of such doped monocrystal multi-component material

Abstract

The invention belongs to the technical field of anode materials for lithium ion batteries and particularly discloses a doped monocrystal multi-component material for lithium ion batteries and a preparation method of such doped monocrystal multi-component material. The doped monocrystal multi-component material and the preparation method thereof have the advantages that nickel-cobalt-manganese ternary materials are modified, and M-source metals are doped when a precursor is prepared to decrease the material sintering temperature and improve material tapping density, so that the mixed arrangement degree of Ni<2+> in a Li<+> layer is weakened obviously; through high-temperature sintering and tempering processes, the precursor of the multi-composite material, prepared through a coprecipitation method, is more stable in crystal structure, metal ions in the material are inhibited from dissolving through surface coating, side reaction between the metal ions and electrolyte is inhibited, and stability and electrochemical performance of an active material are further enhanced; a doped monocrystal multi-component material finished product is stable in crystal structure, high in safety and compaction density and excellent in rate capability and cycle performance, so that specific capacity and charge-discharge voltage of the material are further enhanced; the preparation method is small in doping quantity, simple to operate, easy to control, widely applicable and suitable for large-scale production.

Description

technical field [0001] The invention belongs to the technical field of positive electrode materials for lithium ion batteries, and in particular relates to a kind of single crystal multi-component positive electrode material and a preparation method thereof. Background technique [0002] With the increasing global energy shortage and environmental protection requirements, the development and promotion of electric vehicles has attracted more and more attention from governments around the world, and lithium-ion power batteries, as the core components of power systems, have also received more and more attention. The composition of lithium-ion batteries mainly includes positive electrodes, separators, electrolytes, negative electrodes, and shells. At present, the negative electrode materials mainly use graphite materials with relatively low potential and high capacity, and the price is relatively low. Therefore, the research on cathode materials is one of the key technologies fo...

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Problems solved by technology

Patent CN 105161714 A discloses "a calcium-doped lithium-ion battery ternary cathode material and its preparation method", which uses a solid-phase method and a high-temperature solid-phase sintering method to prepare a calcium-doped lithium-ion battery ternary cathode material; Patent CN 104201371 A discloses "a preparation method of nickel-cobalt-lithium manganese oxide composite positive electrode material", which strengthens the melting reaction between particles and improves the bulk density of the product through the addition of a binder; after high-temperature fusion, The binder remaining on the surface of the nickel-cobalt-lithium manganese oxide composite positive electrode material is used to block the side reaction between the material and the electrolyte; patent CN 104282901 A discloses "a nickel-cobalt-manganese ternary positive electrode material for high conductivity power battery Manufacturing method", the patent uses M metal doping to increase the migration speed of Li+ in the ternary lattice, and TCO gel coating improves the electron migration rate of the ternary cathode material and improves the surface characteristics of the ternary material; however, due to Ni 2+ with Li + The ionic radii are relatively close, and the cation mixing phenomenon is prone to occur, which makes the material prone to lithium precipitation in the air, resulting in poor electrochemical performance of the material.

There are certain defects in the current doping technology: on the one hand, the doping of inactive material elements will lead to the loss of battery capacity; During the process, the surface of the secondary particle is in contact with the electrolyte, and the surface of the active particle of the positive electrode material is eroded by fluoride and dissolved by transition metal ions, resulting in the collapse of the surface structure and deterioration of cycle performance.

Moreover, in the existing process, doping elements will also cause defects such as low initial discharge efficiency of the positive electrode material, low specific capacity and poor cycle performance of the lithium ion battery, and the lithium ion diffusion coefficient, electrical conductivity, and compaction of the material Density, rate performance and safety performance need to be further improved

Therefore, there is no effective solution in the prior art

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