| New sorts of multiple vanadium-based materials are becoming promising anode materials for lithium ion batteries(LIBs) owing to their combined advantages over other materials in terms of low cost, abundance in nature and high theoretical capacity, which have attracted wide attention. However, the lithium storage mechanism of these materials is so complicated that further study is still needed to clarify it. In addition, the electrochemical performance of those materials is unsatisfactory, which should be further optimized.In this paper, we aim to explore the fabrication method and the lithium storage mechanism of multiple vanadium-based materials. The purpose of this paper is to study the key factors that affect the lithium storage capacity and cycle performance of multiple vanadium-based anode materials, and to improve their electrochemical performance via effective ways. The main contents and results are summarized as following:(1) Co V2O6 was successfully prepared via a facile method. The lithium storage mechanism of Co V2O6 was systemically studied, suggesting a structure variation in discharging. During the discharging process, Li V2O5 and Co3V2O8 are firstly formed, then Co3V2O8 transforms into LixV2O5 and Co O, and Co O is reduced into Co subsequently. The discharging process accompanies by an amorphization process. In the subsequent charging, lithium ions are extracted from LixV2O5 and Co is oxidized into Co O. When combining with natural graphite(NG), the Co V2O6 shows excellent electrochemical performance as anode for LIBs. After 100 cycles, the discharge and charge capacity maintain of 669 and 665 m Ah g-1, respectively.(2) An optimized architecture of Ni V3O8 nanoflakes that in situ grown on Ni foam was successfully synthesized. The synthesized Ni V3O8/Ni anode shows good electrochemical performance as anode for Li-ion batteries. After 60 cycles at various rates from 0.1 to 20 C, the discharge capacity can restore to 0.78 m Ah cm-2 when lowering the charge/discharge rate to 0.1 C.(3) Ni V3O8 anode material with good electrochemical compatibility with NG was successfully prepared via facile hydrothermal pretreatment and subsequent sintering. The research results suggest that a novel coordinated electrochemical reconstruction between Ni V3O8 and NG occurs in cycling process, leading to the formation of homogeneous porous architecture. After repeated rate performance from 0.16 to 3.1 A g-1 over 320 cycles, the specific capacity can restore well and shows no obvious attenuation in the subsequent 360 cycles at 0.31 A g-1. Remarkably, the discharge and charge capacities are 819 and 814 m Ah g-1 in the 680 th cycle.(4) Cu V2O6 was successfully prepared via a facile method, and the lithium storage mechanism of Cu V2O6 as the anode for LIBs was studied for the first time. During the discharging process, Li V2O5 and Cu3V2O8 are firstly generated, then Cu3V2O8 transforms into LixV2O5 and Cu O, and Cu O is finally reduced into Cu. The discharging process accompanies by an amorphization process. In the charging process, lithium ions are extracted from LixV2O5, and Cu is oxidized into Cu O. The electrochemical performance of Cu V2O6 and be largely improved via combining it with NG. The Cu V2O6/NG electrode delivers initial discharge and charge capacities of 725 and 453 m Ah g-1 at a specific current of 110 m A g-1, maintaining of 537 and 533 m Ah g-1 after 200 cycles.(5) Zn3V3O8 nanosheets with porous architecture were fabricated via hydrothermal pretreatment and subsequent sintering. The Zn3V3O8 is demonstrated to be a new anode material with a possible insertion/extraction mechanism. Remarkably, the Zn3V3O8 shows superior electrochemical performance incorporating with NG, which exhibit discharge and charge capacities of 541 and 537 m Ah g-1 after 200 cycles at a specific current of 120 m A g-1. |
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