Preparation method of sodium ion battery negative electrode material

By modifying biomass-based hard carbon materials through reactive melt extrusion and restricted foaming processes, a disordered layer graphite structure co-doped with nitrogen and boron heteroatoms is formed. This solves the problem of balancing volumetric energy density and specific capacity in the preparation of biomass-based hard carbon anode materials, thereby improving the electrochemical performance and cycle stability of the battery.

CN122102097APending Publication Date: 2026-05-29GUANGDONG DONGDAO NEW ENERGY +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
GUANGDONG DONGDAO NEW ENERGY
Filing Date
2026-01-27
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing biomass-based hard carbon anode materials are difficult to balance with high volumetric energy density and high specific capacity during preparation. Furthermore, their large specific surface area and uncontrollable pore structure result in low coulombic efficiency and poor cycle stability in the first cycle.

Method used

By employing reactive melt extrusion and confined foaming processes, urea, boric acid, and polyethylene glycol are used to form a eutectic fluid that is in-situ permeates and modifies biomass raw materials. Combined with physical confining pressure to control the microstructure, a random layer graphite structure co-doped with nitrogen and boron heteroatoms is formed, which suppresses excessive expansion and surface opening and constructs a closed-cell structure.

Benefits of technology

A hard carbon material with high specific capacity, low specific surface area and high tap density was achieved, which improved the first-cycle coulombic efficiency and volumetric energy density of sodium-ion batteries, and improved the electrochemical performance and cycle stability of the material.

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Abstract

The application discloses a preparation method of a sodium ion battery negative electrode material. The method mixes biomass raw materials, urea, boric acid and polyethylene glycol, forms a low eutectic fluid through a reactive melt extrusion process, and penetrates into the biomass in situ; then, oxidation foaming and cross-linking curing are carried out under a physical limiting pressure, and finally, high-temperature carbonization is carried out to obtain a hard carbon material. The application utilizes the synergistic effect of extrusion shearing and physical limiting to realize nitrogen and boron co-doping and precise control of the micro-pore structure, and the prepared negative electrode material has an expanded interlayer spacing, rich closed pore structure and high tap density. The method does not require a solvent, the process is continuous, effectively solves the problem that the volume energy density and specific capacity of the hard carbon material are difficult to be considered, and significantly improves the sodium storage capacity, rate performance and first cycle coulombic efficiency of the battery.
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