High performance Li 3V 2(PO 4) 3/C composite cathode material for lithium ion batteries studied in pilot scale test

Abstract

Li 3V 2(PO 4) 3/C composite cathode material was synthesized via carbothermal reduction process in a pilot scale production test using battery grade raw materials with the aim of studying the feasibility for their practical applications. XRD, FT-IR, XPS, CV, EIS and battery charge–discharge tests were used to characterize the as-prepared material. The XRD and FT-IR data suggested that the as-prepared Li 3V 2(PO 4) 3/C material exhibits an orderly monoclinic structure based on the connectivity of PO 4 tetrahedra and VO 6 octahedra. Half cell tests indicated that an excellent high-rate cyclic performance was achieved on the Li 3V 2(PO 4) 3/C cathodes in the voltage range of 3.0–4.3 V, retaining a capacity of 95% (96 mAh/g) after 100 cycles at 20 C discharge rate. The low-temperature performance of the cathode was further evaluated, showing 0.5 C discharge capacity of 122 and 119 mAh/g at −25 and −40 °C, respectively. The discharge capacity of graphite//Li 3V 2(PO 4) 3 batteries with a designed battery capacity of 14 Ah is as high as 109 mAh/g with a capacity retention of 92% after 224 cycles at 2 C discharge rates. The promising high-rate and low-temperature performance observed in this work suggests that Li 3V 2(PO 4) 3/C is a very strong candidate to be a cathode in a next-generation Li-ion battery for electric vehicle applications.