A kind of single crystal nickel cobalt lithium manganate cathode material and preparation method and application thereof

Abstract

The invention discloses a single-crystal nickel-cobalt-manganese lithium manganate positive electrode material and a preparation method and application thereof. The positive electrode material has a core-shell structure, and the material of the core layer is a high-nickel-nickel-cobalt-manganese ternary single crystal positive electrode material; Materials include Li r (Ni s Co t Mn 1‑s‑t )O 2 (II), metal oxides and metal metaphosphates, in formula (II), 0.9≤r≤1.05, 0.3≤s≤0.5, 0<t<0.4, 1‑s‑t>0; by mass percentage In total, in the material of the shell layer, formula (II) accounts for more than 50%, and the mass ratio of metal oxide to metal metaphosphate is 1:0.1-10; preparation: the precursor of formula (II) and metal oxide are mixed. It is mixed with metal metaphosphate to disperse and grind, mixed with lithium source and sintered to obtain shell layer material and mixed with core layer material to sinter to form the positive electrode material; the positive electrode material can work under 4.5V high voltage and has ideal Cyclic stability performance.

Description

technical field [0001] The invention belongs to the field of lithium ion battery electrode materials, in particular to a positive electrode material, in particular to a single crystal nickel cobalt lithium manganate positive electrode material and a preparation method and application thereof. Background technique [0002] Nowadays, with the continuous improvement of the capacity requirements of lithium-ion batteries for pure electric vehicles, hybrid electric vehicles and portable energy storage devices, people expect to develop lithium-ion batteries with higher energy density and power density to achieve long-term battery life and energy storage. Increasing the working voltage of the battery is one of the effective ways to improve the energy density of the lithium-ion battery. However, increasing the working voltage will cause a series of problems such as the degradation of the cycle performance of the lithium-ion battery. The precipitation of the battery increases the pola...

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Problems solved by technology

[0002] Nowadays, with the continuous improvement of lithium-ion battery capacity requirements for pure electric vehicles, hybrid vehicles and portable energy storage devices, people expect to develop lithium-ion batteries with higher energy density and power density to achieve long-term battery life and energy storage. Increasing the working voltage of the battery is one of the effective ways to increase the energy density of the lithium-ion battery. However, increasing the working voltage will cause a series of problems such as the degradation of the cycle performance of the lithium-ion battery, such as the increase of side reactions at the electrode / electrolyte interface and the increase of oxygen The precipitation increases the polarization and internal resistance of the battery, leading to the problem of poor cycle life

In order to improve the thermal stability and cycle performance of ternary materials under high voltage, common methods include coating and modifying ternary cathode materials. However, although the current ternary materials have been coated and modified, they still cannot perform well Coated on the surface of the positive electrode material, and cannot effectively reduce the reaction of the electrolyte / material interface under high voltage, the cycle stability is poor, and it is difficult to meet the actual needs

At the same time, the traditional secondary spherical particle structure is poor in firmness, and its skeleton structure is easily damaged under higher voltage, which leads to aggravated electrode / solution interface reaction, resulting in a decrease in battery performance.

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