Facile synthesis of S-doped LiFePO₄@N/S-doped carbon core-shell structured composites for lithium-ion batteries

Heteroatom-doped carbon can significantly improve the electrochemical performance of LiFePO4 cathodes, but it is limited by the complex preparation process and expensive dopants. A self-assembled S-doped LiFePO4@N/S-doped C core-shell structured composites were synthesized by a convenient solvothermal method are reported. The structure and the electrochemical performance of the composites were characterized. In the S-doped LiFePO4@N/S-doped C composites, the glucose-derived carbon microspheres were attached by LiFePO4/C particles to form secondary particles in the core-shell structure. The thioacetamide regulated the morphology of LiFePO4/C particles and provided N and S atoms to dope the composites. The S-doped LiFePO4@N/S-doped C composites delivered specific discharge capacities of 157.81 mAh g-1 at 0.1 C and 121.26 mAh g-1 at 5 C, and capacity retention of 99.88% after 100 charge/discharge cycles. The excellent electrochemical performance of the S-doped LiFePO4@N/S-doped C composites can be attributed to the synergism of thioacetamide and glucose.