High-capacity, high-magnification and high-tap-density sodium ion battery positive electrode material and preparation method thereof

Abstract

The invention discloses a high-capacity, high-magnification and high-tap-density sodium ion battery positive electrode material and a preparation method thereof. The preparation method comprises the following steps of preparing a manganese-nickel-cobalt carbonate spherical precursor by adopting a coprecipitation method, uniformly mixing the manganese-nickel-cobalt carbonate spherical precursor with a lithium source, and calcining to obtain a spherical lithium-rich manganese-based positive electrode material, and carrying out ion exchange post-treatment on the spherical lithium-rich manganese-based positive electrode material to obtain the sodium ion battery positive electrode material with high capacity, high rate and high tap density. Through the combined action of the crystal nucleation control agent and the complexing agent, the crystallization surface energy of a coprecipitation system is reduced, micron-sized compact spherical particles are constructed to improve the tap density of the material, and low-melting-point sodium salt and the lithium-rich material are subjected to an ion exchange reaction, so that part of lithium ions in the lithium-rich material are exchanged with sodium ions, meanwhile, part of transition metal ions are removed, sodium ion embedding and transition metal vacancy construction are jointly achieved, and the defect that a lithium-rich material cannot be directly used as a high-capacity sodium ion positive electrode material is overcome.

Description

technical field [0001] The invention belongs to the technical field of material synthesis, and in particular relates to a high-capacity, high-rate and high-tap-density sodium-ion battery cathode material and a preparation method thereof. Background technique [0002] Room temperature sodium-ion batteries have many advantages such as abundant resources, low cost, high energy conversion efficiency, strong constant power discharge capability, and low maintenance cost. Sodium-ion battery technology has long been considered an important technical link in the development of large-scale energy storage systems and smart grid applications. In recent years, research on sodium-ion batteries has continued to deepen, and the starting point is to develop high-energy, low-cost electrode materials for sodium-ion batteries. At present, the main bottleneck limiting the improvement of energy density and cost reduction of sodium-ion batteries lies in the cathode material. [0003] The current...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of high raw material cost, low tap density, poor rate performance and fast capacity decay of sodium ion positive electrode materials based on the redox reaction of anions, and provide a high capacity, high rate and high tap density sodium Ion battery positive electrode material and preparation method thereof, the positive electrode material is prepared through three steps of precursor preparation, lithium sintering and sodium ion exchange post-treatment

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