Sodium ion secondary battery positive electrode material and preparation method and application thereof

Abstract

The invention discloses a sodium ion secondary battery positive electrode material and a preparation method and application thereof. The invention relates to the technical field of sodium-ion batteries. The sodium ion secondary battery positive electrode material comprises sodium ion battery positive electrode material particles and Prussian blue analogue nano-particles, the diameters of the sodium ion battery positive electrode material particles are greater than that of the Prussian blue analogue nano-particles, and the outer surfaces of the sodium ion battery positive electrode material particles are coated with Prussian blue analogue nano-particle layers. According to the invention, the positive electrode materials with different sizes are blended and surfaces of larger particles are coated with materials with smaller particles through a mechanical milling method; the preparation process is simple and practical, and the obtained positive electrode material of the sodium ion secondary battery can effectively improve the cycling stability of the battery, the contact between an electrolyte and the positive electrode material is reduced and the capacity retention ratio is improved.

Description

technical field [0001] The invention belongs to the technical field of sodium ion batteries, and in particular relates to a cathode material for a sodium ion secondary battery and a preparation method and application thereof. Background technique [0002] Sodium and lithium in sodium-ion batteries have similar physical and chemical properties, and the sodium element is widely distributed, and its content in the earth's crust is 350 times that of lithium, so it is considered to be a secondary energy storage system with great potential to replace lithium-ion batteries. Cathode materials, as an important part of Na-ion batteries, play a crucial role in their electrochemical performance. Among them, layered transition metal oxide cathode materials exhibit high energy density, simple structure, and easy preparation in sodium-ion batteries, and are considered to be a promising cathode material. However, transition metal oxides generally have a layered structure with high energy d...

AI Technical Summary

Problems solved by technology

[0004] 1. Oxide coating: the oxide used is electrochemically inert, does not contribute capacity during charge and discharge, and reduces the energy density of the battery;

[0005] 2. Sodium fast ion conductor coating: the positive electrode material and the coating material need to be fired after being mixed, and the operation is complicated; such as CN106684369 B;

[0007] In addition, in the positive electrode materials of sodium ion batteries, although the positive electrode materials of the O3 phase have high theoretical specific capacity, they have high surface activity and unstable structure, so the cycle stability is poor.

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