Layered monodiphosphate Li9V3(P2O7)3(PO4)2: A novel cathode material for lithium-ion batteries

✍ Scribed by Quan Kuang; Jiantie Xu; Yanming Zhao; Xiaolong Chen; Liquan Chen

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 912 KB
• Volume: 56
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2010.11.051

✦ Synopsis

Single phase Li 9 V 3 (P 2 O 7 ) 3 (PO 4 ) 2 is synthesized at 750 • C via solid-state reaction method for the first time. The Rietveld refinement results show that the trigonal system (space group: P 3c1) with the lattice parameters a = 0.9724 nm, c = 1.3596 nm are obtained. Its intrinsic electrical conductivity of 1.43 × 10 -8 S cm -1 is higher than that of LiFePO 4 and as the same order of Li 3 V 2 (PO 3 ) 4 . The electrochemical measurement results show that there are two plateaus (3.77 V and 4.51 V) and three plateaus (3.77 V, 4.51 V and 4.75 V) in the potential ranges of 2.0-4.6 V and 2.0-4.8 V, respectively. In the range of 2.0-4.6 V, two discharge plateaus (4.46 V and 3.74 V) can be observed and 110 mAh g -1 of discharge capacity is achieved. The Rietveld refinement result of the X-ray diffraction (XRD) data at the end of discharge after the first cycle suggests that the structural reversibility can be retained during electrochemical reactions in Li 9 V 3 (P 2 O 7 ) 3 (PO 4 ) 2. In the range of 2.0-4.8 V, almost six lithium ions are extracted and the trigonal structure is still recovered after 30 cycles. Therefore, this novel layered vanadium monodiphosphate offers a promising candidate as cathode material for lithium-ion batteries.