A novel high-potential multi-layer carbon-coated polyanion sodium-ion battery cathode material and preparation method thereof

Abstract

A high-potential polyanionic sodium-ion battery positive electrode material and a preparation method thereof. The preparation method is a high-energy sanding-freeze-drying method, which can construct a three-dimensional carbon coating network, and includes the steps of precursor powder preparation and drying, subsequent calcination, and freeze-drying. The technological process is simple, the equipment investment is low, the degree of continuity is high, the cost is controllable, and it is easy to industrially scale up, and the obtained product has uniform particles and high purity, and the carbon layer is uniform. High-potential polyanionic sodium-ion battery cathode material with excellent electrochemical performance, 0.1C discharge capacity as high as 107.9mAh g ‑1 , the energy density can reach 400Wh kg ‑1 And the cycle performance is good, the capacity retention rate of 300 cycles at 0.5C rate is more than 90%; the capacity retention rate of 800 cycles at 5C rate is close to 81%. In addition, the material has good thermal stability and low cost of raw materials, and is a very competitive cathode material for a new generation of sodium-ion batteries.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for sodium ion batteries. More specifically, the present invention relates to a novel high-potential multi-layer carbon-coated positive electrode material for polyanion type sodium ion batteries, and also relates to a preparation method of the material. Background technique [0002] In recent years, the global environmental problems have become increasingly serious, and the development of new renewable energy sources has become imminent. As the most promising sustainable energy source, lithium-ion batteries have been widely used in various fields such as portable mobile devices, electric vehicles, and energy storage due to their high safety, high energy density, and long service life. However, due to the extremely uneven distribution of global lithium resources and the current rapid and large consumption, its production and use costs will inevitably be greatly affected. Therefore, sod...

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Problems solved by technology

Among them, the sol-gel method is very complicated, and the organic solvent used is relatively expensive; the hydrothermal method consumes a lot of energy, the phase formation process is relatively complicated, and the intermediate process is uncontrollable; the high-temperature solid-phase method has a long calcination time, and raw materials are not mixed Uniformity, poor consistency, etc.

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