Macroporous network Li3V2(PO4)3/C cathode material with excellent high-rate performance for lithium-ion batteries

Abstract

Macroporous network Li₃V₂(PO₄)₃/C was successfully synthesized by rheological phase method using ethanol and 1,2-propylene glycol as a mixed solvent. At the same time, Li₃V₂(PO₄)₃/C via a single ethanol solvent was prepared for comparison. XRD analysis of the two samples confirmed the formation of high purity and well-crystallized Li₃V₂(PO₄)₃/C. The SEM results reveal that there is a significant difference in morphologies between the two samples, the one by single ethanol shows a flake-like morphology, while the other one presents a macroporous network morphology. The sample with a macroporous network morphology shows discharge capacities of 154, 138, 130, 120, 101, 93, 83 and 70 mA h g⁻¹ at 1C, 3C, 5C, 10C, 20C, 30C, 40C and 50C (1C = 150 mA g⁻¹) in the voltage range of 3.0–4.8 V, respectively, which are better than those of the Li₃V₂(PO₄)₃/C sample with a flake-like morphology. In summary, it is demonstrated that the Li₃V₂(PO₄)₃/C cathode material using a mixed solvent can deliver a significantly improved high rate performance in the voltage range of 3.0–4.8 V, which can be mainly ascribed to the macroporous network morphology.