A core-shell structure al/la co-doped high-nickel ternary precursor and its preparation method, and a positive electrode material

Abstract

The invention relates to the field of lithium-ion battery materials, and proposes a core-shell structure Al / La co-doped high-nickel ternary precursor and a preparation method thereof, as well as a positive electrode material prepared from the precursor. The preparation method is mainly divided into three steps. The first step is to synthesize a rod-shaped Al-doped high-nickel ternary precursor at a low pH; The precursor is the core to grow a needle-shaped La-doped high-nickel ternary precursor shell, and an Al / La co-doped high-nickel ternary precursor with a core-shell structure is synthesized; in the third step, the core-shell structure The Al / La co-doped high-nickel ternary precursor is mixed with lithium salt and calcined at high temperature in an oxygen atmosphere to obtain the core-shell structure Al / La co-doped ternary positive electrode material. This unique co-doped core-shell structure effectively enhances the stability of the internal structure, inhibits the generation of impurity phases such as cation mixing and rock-salt structure, reduces the fragmentation of grain boundaries, improves the average oxidation state of manganese ions, and effectively inhibits Jahn‑ The occurrence of the Teller effect reduces the rapid decay of the capacity during the cycle process, and significantly improves the cycle stability and cycle life of the material. The invention adopts the co-precipitation method to synthesize products with uniform components, good sphericity, good reproducibility, easy control of conditions, low preparation cost, high economic value and wide application prospect.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a core-shell structure Al / La co-doped high-nickel ternary precursor and a preparation method thereof, and a core-shell structure Al / La co-doped high-nickel ternary positive electrode Material. Background technique [0002] Lithium-ion batteries (LiBs) play an important role in clean energy due to their low cost, high energy density, and long lifetime. The cathode materials for the new generation of lithium-ion batteries require higher energy density, longer cycle life, and better safety for electric vehicles and energy storage. Nickel-rich (Ni content>60%) cathode material LiNi x co y mn 1-x-y o 2 (NCM) and LiNi x co y Al 1-x-y o 2 (NCA) can basically meet the requirements. However, nickel-rich materials face defects such as degradation of material structure and poor thermal stability under high voltage and high temperature. This is due to the low cont...

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Problems solved by technology

Using CO 3 2- To improve the crystallization of the precipitant, although the oxidation problem of Mn is avoided, the electrochemical performance of the material cannot be fundamentally improved by simply improving the precipitant.

Meanwhile, in Li + The problem that the transmission channel is blocked by the gap between the core and the shell during the deintercalation process is also not solved

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