Influence of synthesis approach on the electrochemical properties of (Li3V2(PO4)3-LiVOPO4)/graphite composite material for Li-ion batteries

• Published in: Materials today communications 2021-12, Vol.29, p.102955, Article 102955
• Main Authors: Ahsan, Zishan, Wang, Shuai, Cai, Zhenfei, Ma, Yangzhou, Song, Guangsheng, Zhang, Shihong, Yang, Weidong, Wen, Cuie
• Format: Article
• Language: English
• Subjects: (Li3V2(PO4)3-LiVOPO4)/graphite composite; Cycling stability; Electrochemical performance; Li-ion Battery; Multi-electron cathode materials; Wide voltage window
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2021.102955

In this work, a dual-phase Li3V2(PO4)3-LiVOPO4 cathode material was synthesized using a novel vanadium-excess sol-gel process, followed by the addition of graphite by compositing in-situ or ball milling mixing. The different graphite addition approaches did not affect the ratio of the two phases in the composite but significantly influenced its electrochemical performance. The Li3V2(PO4)3-LiVOPO4/G sample prepared by in-situ compositing showed a special flake-like morphology with a uniform distribution of graphite and the cathode material showed significantly superior electrochemical performance in a wide voltage window of 1.5–4.5 V with discharge capacities of 281, 250, and 211 mAh g−1 at a discharge rate of 0.2 C, 1 C, and 10 C, respectively, as well as higher capacity retention of 88% and 67% after 100 and 650 cycles at high discharge rates of 1 C and 10 C, compared to its ball milling mixed counterpart. The excellent electrochemical performance can be ascribed to the mutual modifications induced by in-situ graphite addition and their synergistic effects. •The Li3V2(PO4)3-LiVOPO4/graphite composites are synthesized.•The effects of graphite addition approach are studied in different voltage ranges of 1.5–4.5 V, 2.8–4.5 V and 1.5–2.8 V.•The synergistic effects of different components and their corresponding charge storage mechanisms are analysed.•The composite displayed 67% capacity retention at high rate of 10 C after 650 cycles in wide voltage range1.5–4.5 V, 1.5–2.8 V.