| 摘要 |
A method of preparing LiFePO<SUB>4</SUB>/Li<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3 </SUB>composite cathode materials and their applications as cathode materials for lithium ion batteries are disclosed. The preparation method includes the following steps: (A) providing a mixture of iron powder, lithium salt, vanadium salt, and a phosphate salt whereafter these compounds are dissolved into a mixed acid solution; (B) drying the solution in order to obtain precursor powders; and (C) heating the precursor powders at a temperature ranging between 400 and 1000° C. to form LiFe<SUB>1-y'</SUB>V<SUB>y'</SUB>PO<SUB>4</SUB>/Li<SUB>3</SUB>V<SUB>2-y''</SUB>Fe<SUB>y''</SUB>(PO<SUB>4</SUB>)<SUB>3 </SUB>composite powders. Alternatively, prepare the composite cathode by preparing olivine LiFe<SUB>1-y'</SUB>V<SUB>y'</SUB>PO<SUB>4 </SUB>and monoclinic Li<SUB>3</SUB>V<SUB>2-y'</SUB>Fe<SUB>y''</SUB>(PO<SUB>4</SUB>)<SUB>3 </SUB>powders as in previous procedures followed by mixing adequately. The low cost of iron powder thus facilitates to prepared composite cathode materials exhibiting higher electrical conductivity and superior cycling performance at high C rates than those of olivine LiFe<SUB>1-y'</SUB>V<SUB>y'</SUB>PO<SUB>4 </SUB>and monoclinic Li<SUB>3</SUB>V<SUB>2-y''</SUB>Fe<SUB>y''</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>. The invention will help the development of the lithium ion batteries and related industries.
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