LIMN_1-XFE_XPO₄ CATHODE MATERIAL HAVING CORE-SHELL STRUCTURE, PREPARATION METHOD THEREFOR, AND LITHIUM-ION BATTERY

摘要

The present invention provides a cathode material having a core-shell structure, consisting of a core and a shell. The core is LiMn_1-xFe_xPO₄ nanoparticles; the shell is a mixture of carbon and a lithium-containing metal sa the lithium-containing metal salt is a lithium-containing metal phosphate and/or a lithium-containing metal pyrophosphate, wherein 0x0.5. According to the present invention, LiMn_1-xFe_xPO₄ nanoparticles are adopted as the core, and the nanosized material can shorten the diffusion path of lithium ions, reduce the diffusion time of lithium ions among particles, and improve the ionic transport property of the material. A mixture of carbon and a lithium-containing metal phosphate and/or a lithium-containing metal pyrophosphate is adopted as a coating layer, and the addition of the lithium-containing metal phosphate and/or pyrophosphate can increase the ionic conductivity of the material on one hand, and effectively improve the carbon coating effect on the other hand. Thus, the rate performance and the cycling performance of the cathode material having a core-shell structure are significantly improved, and the cathode material having a core-shell structure can also have a higher compact density.