Binary-doping single-crystal ternary positive electrode material and preparation method thereof

Abstract

The invention provides a binary-doping single-crystal ternary positive electrode material and a preparation method thereof. The chemical expression of the binary-doping single-crystal ternary positiveelectrode material is Li<1+y+z>NiCoMn<c>A<y>B<z>O<2>, wherein 1>a>b>=c>0, a >=0.5, (a+b+c) is equal to 1, 0.05>=y>=0.001, 0.005>=z>=0.001, A is a first doping element and is selected from at least one of Mg and Al, and B is a second doping element and is selected from at least one of Ti, V, B, Sb, La and T. In the single-crystal ternary positive electrode material, the single-crystal ternary positive electrode material with excellent comprehensive performance is obtained by adjusting types and proportions of doping substances, the discharging specific capacity and the cycle stability both are improved to a certain extent, oxygen relief temperature at 4.3V is relatively high, and the application safety of a lithium battery can be met; and meanwhile, the preparation method of the binary-doping single-crystal ternary positive electrode material is simple and available in raw material, and the binary-doping single-crystal ternary positive electrode material is a single-crystal ternary positive electrode material, suitable for large-scale commercial production, for a lithium ion battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a binary doped single crystal ternary positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been continuously developed since they were successfully commercialized by Sony in 1991. Lithium-ion batteries are considered to be the best choice for energy storage devices and power sources in the field of new energy because of their superior characteristics such as high energy density, long cycle life, and environmental protection; Due to the environmental pollution, electric vehicles driven by electricity came into being, which requires the battery in the power source to carry high-quality electric energy as much as possible within a limited space and within a controllable quality range. The current commercial lithium-ion battery cathode materials are mainly: lithium iron phosphate (LiFePO 4 ), lithium ma...

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Problems solved by technology

However, these dopings have certain defects: the inactive material elements introduced by doping will lead to a decrease in the capacity of the battery, and generally the doped ternary positive electrode materials are mostly spherical secondary particles, and the doping is also limited to the size of the secondary particles. Surface, while the primary particles do not effectively participate in the doping process, the cycle stability and safety of the battery under high voltage still need to be improved

However, in these doping methods, the doping elements are often not uniformly distributed in the positive electrode material, and its capacity and stability will also be affected, and it is impossible to form a single crystal ternary positive electrode material with large particle size after doping

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