Molten metal coated ternary precursor and preparation method thereof

Abstract

The invention discloses a molten metal coated ternary precursor and a preparation method thereof. The component of the coated ternary precursor is NiaCobMnc (OH) 2Med, a + b + c = 1, 0.6 < = a < 1, 0< b < 0.4, 0 < c < 0.4, 0.05% < = d < = 0.5%; and Me is one or more of low-melting-point metals such as Bi, Ga, Pb and Sn with melting points below 600 DEG C. According to the preparation method, thesurface of the precursor is uniformly coated with the coating agent through coating of the molten metal liquid, the effect of coating metal is brought into full play, and the ternary lithium ion positive electrode material prepared from the precursor improves the structural stability of the material and prolongs the cycle life of a battery.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and specifically relates to a molten metal-coated ternary precursor and a preparation method thereof. [0002] technical background [0003] As a high tap density, high gram capacity, and high voltage cathode material, lithium-ion ternary cathode materials are currently one of the best choices for the preparation of power batteries, but their high temperature stability and cycle performance are relatively lacking, which is the bottleneck restricting their wide application. As the market demand for energy density continues to increase, ternary cathode materials continue to develop in the direction of high nickel, but with the increase of nickel content, the defects of temperature stability and cycle performance of ternary materials become more and more obvious. [0004] Coating and doping ternary materials is one of the simple and effective methods to improve their high temperature stabili...

AI Technical Summary

Problems solved by technology

[0004] Coating and doping ternary materials is one of the simple and effective methods to improve their high temperature stability and cycle performance. The current mainstream process mainly focuses on mixing ternary precursors with nano-oxides and then sintering at high temperature. , although this mixing method is simple to operate, its essence is the mixing of solids and nanoparticles. First, the nanoparticles themselves are easy to agglomerate and difficult to disperse; -Solid coating is relatively more macroscopic than wet coating, and it is difficult to guarantee the uniformity of coating

[0005] Recently, there have been many reports on wet coating and doping of ternary elements, such as patent CN106654197A, which uses co-precipitation method to coat Al and Mg elements on the surface of ternary elements, and patent CN11012777A, which adopts wet method to dope nickel-cobalt-aluminum ternary element with zirconium concentration gradient Materials, these methods mentioned are all soluble inorganic compounds with the addition of required elements to form hydroxide precipitates at alkaline pH, but it should be pointed out that Ni(OH) 2 、Co(OH) 2 Mn(OH) 2 , Al(OH) 3 , Mg(OH) 2 , Zr(OH) 2 The KSPs were 6 x 10 -16 , 1.6×10 -15 , 4×10 -14 , 3.2×10 -34 , 1.8×10 -11 , 2×10 -48 It can be seen that Al, Mg, Zr hydroxide solubility constants are much different than Ni, Co, Mn solubility constants, and during co-precipitation, the precipitation sequence difference is relatively large, which easily leads to uneven coating; although patent CN106654197A introduces network complexing agent to slow down the difference in solubility constant, but a small amount of complexing agent is difficult to make up the difference between Al, Mg and Ni, Co, Mn, and too much complexing agent will easily lead to precipitation difficulties, affecting production and yield, and Increased wastewater treatment costs

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