Large-scale synthesis of Li3V2(PO4)3@C composites by a modified carbothermal reduction method as cathode material for lithium-ion batteries

Abstract

Carbon coated Li₃V₂(PO₄)₃ composites were prepared by a modified carbothermal reduction method. The method has the advantages of being simple and scalable, while the whole synthesis is devoid of any reducing/protecting gases, therefore, it can be directly carried out in muffle furnace. The obtained Li₃V₂(PO₄)₃@C composites have particles sizes from 500 nm to 3 μm, and with homogeneous carbon coating layer thickness of about 7 nm. The battery based on this Li₃V₂(PO₄)₃@C composites cathode exhibits a specific discharge capacity of 130.9 mA h g⁻¹ at 0.1 C, and exhibits an initial specific discharge capacity of 102.8 mA h g⁻¹ even at 10 C and almost keeps 96.6% of initial capacity retention after 500 cycles. The performance enhancement can be directly ascribed to the robust structure merits of the Li₃V₂(PO₄)₃@C composites synthesized by the modified carbothermal reduction method. Furthermore, the as-developed method has the potential to be expanded to other lithium transition-metal phosphates (such as lithium iron phosphate), which conventionally need to be sintered in reductive or protective atmospheres.