Method for manufacturing lithium iron phosphate (li2fepo4) cathode material having a high initial charge

The C-LiFePO4-Si composite with Fe-site and Li-site co-doping addresses LiFePO4's cycling limitations by creating additional storage sites and reducing defects, enhancing capacity and stability while eliminating the need for excess lithium, thus lowering production costs.

WO2026155639A1PCT designated stage Publication Date: 2026-07-23OCP SA
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
OCP SA
Filing Date
2026-01-13
Publication Date
2026-07-23

AI Technical Summary

Technical Problem

Lithium iron phosphate (LiFePO4) cathode materials suffer from limited cycling performance due to the formation of a solid electrolyte interphase film (SEI) that consumes Li ions, leading to high production costs when excess lithium is used to compensate for this loss, and existing methods for improving conductivity and capacity are costly and time-consuming.

Method used

A process involving the formation of a C-LiFePO4-Si composite by coating Si particles with carbon-coated LiFePO4 particles, creating additional lithium storage sites, and employing Fe-site and Li-site co-doping to reduce defects, using a high-purity LiFePO4 precursor with a specific Fe/P ratio.

Benefits of technology

Enhances the initial specific charge capacity and reduces the need for costly excess lithium by forming additional lithium storage sites and suppressing defects, resulting in higher capacity and improved cycling stability.

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Abstract

The present invention relates to a preparation method for a batch of the lithium iron phosphate (LiFePO4) cathode material. The method consists in coating the surface of the silicon (Si) particles with lithium iron phosphate (LiFePO4) particles to form a C-LiFePO4-Si composite. A large number of LiFePO4-Si interfaces are formed at the contact points between the LiFePO4 and Si particles, where the Si-O oxygen-containing particles are generated at the interfaces, acting as an additional lithium store, thereby contributing to additional capacity. The method also uses co-doping of the Fe site and the Li site to suppress Fe / Li antisite defects, further improving the initial charge capacity. In addition, by using a precursor of the LiFePO4 ratio, the LiFePO4 cathode material prepared by this method makes it possible to achieve an initial charge capacity of greater than 166 mAh / g. The invention also relates to the LiFePO4 cathode material, to a lithium-ion battery that uses this cathode and to a lithium-ion battery that uses this cathode material.
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