Facile synthesis of S-doped LiFePO ₄ @N/S-doped carbon core–shell structured composites for lithium-ion batteries

Abstract Heteroatom-doped carbon can significantly improve the electrochemical performance of LiFePO ₄ cathodes, but it is limited by the complex preparation process and expensive dopants. A self-assembled S-doped LiFePO ₄ @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 LiFePO ₄ @N/S-doped C composites, the glucose-derived carbon microspheres were attached by LiFePO ₄ /C particles to form secondary particles in the core–shell structure. The thioacetamide regulated the morphology of LiFePO ₄ /C particles and provided N and S atoms to dope the composites. The S-doped LiFePO ₄ @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 LiFePO ₄ @N/S-doped C composites can be attributed to the synergism of thioacetamide and glucose.