A method for preparing anion-occupied Prussian blue cathode material and its energy storage application.

CN117585685BActive Publication Date: 2026-03-13BEIJING INST OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2022-08-17
Publication Date
2026-03-13

AI Technical Summary

Technical Problem

The problem of bound water occupying lattice defect vacancies in existing Prussian blue materials leads to interruption of electron transport channels, obstruction of sodium ion migration pathways, reduced reactivity, and decreased cycle stability, making it difficult to meet the needs of large-scale commercial production.

Method used

Anionic occupied Prussian blue material (LI-PB) was prepared by using a co-precipitation method, in which the bound water content and defect structure stability were controlled by the strong polar anion BF4- occupying the bound water sites. The mixture consisted of an aqueous solution of sodium ferrocyanide, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIF) ionic liquid and sodium chloride. After co-precipitation, the mixture was centrifuged, washed with water, washed with alcohol, and freeze-dried.

Benefits of technology

The improved structural stability and sodium content of the material enhance the cycle stability and specific capacity of sodium-ion batteries, forming a stable SEI film and improving the safety performance and cycle life of the battery.

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Abstract

This invention provides a method for preparing anion-occupied Prussian blue cathode material and its energy storage application. The molecular formula of the PB cathode material is Na. x M n [Fe(CN)6] 1‑y γ 6y‑j F j □ y Where 0 < x ≤ 2, 0 < n ≤ 1, 0 < y < 1, 0 < j ≤ 6y; M is a divalent or trivalent transition metal; γ is bound water; □ is a vacancy; F is the anion BF4. ‑ A stable, low-defect Prussian blue (PB) material was constructed by inducing anion occupancy through co-precipitation. The anions partially or completely replaced bound water and coordinated with M, forming a stable crystal structure with low bound water content. A sodium-ion battery was assembled using this ion-occupied Prussian blue cathode material, achieving a performance of 50 mA g⁻¹. ‑1 At current density, the initial charging specific capacity is 126 mA hg ‑1 The cycle efficiency remained close to 100%, and the capacity retention rate was 61.54% after 400 cycles.
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Citation Information

Patent Citations

  • Prussian blue transition metal cyanide, preparation method thereof, and positive pole piece, secondary battery, battery pack and device related to prussian blue transition metal cyanide

    CN112259730A

  • Method of producing a sodium iron(II)-hexacyanoferrate(II) material

    US20190270649A1