Li3VO4 (LVO) is a promising anode material for use in Li-ion batteries (LIBs) owing to its safe discharge plateau and high capacity. However, its moderate Li+-diffusion coefficient and low electrical conductivity pose challenges to its widespread use in the LIB industry. In this study, hexavalent tungsten ions (W6+) were introduced to boost electrochemical kinetics, and W6+-doped LVO microspheres were successfully prepared using a spray-drying approach. Density functional theory (DFT) calculations reveal that the enhanced electronic conductivity and improved oxygen lattice following W6+ doping is possibly due to the development of a mid-gap state positioned above the valence band maximum. The doped LVO displayed excellent electrochemical performance, including a superior rate capability (288.9 mAh/g at 10C) and remarkable cycling stability (capacity fading of only 8.6 % over 200 cycles at 6C), which is ascribable to improved electrical conductivity and Li+ insertion/extraction. In addition, we also fabricated a 3.7 V full LIB with a W6+-doped LVO anode and a LiNi0.5Mn1.5O4 (LNMO) cathode, and a lithium-ion capacitor (LIC) with an energy density of 131.8 Wh/kg using the modified LVO and active carbon (AC). This study demonstrates the potential of W6+-doped LVO for use in energy-storage applications.

中文翻译：

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推进Li3VO4作为高性能负极材料在锂离子电池和锂离子电容器中的应用


Li3VO4（LVO）由于其安全放电平台和高容量而成为一种很有前景的锂离子电池（LIB）负极材料。然而，其适中的Li+扩散系数和低电导率对其在锂离子电池行业的广泛应用提出了挑战。在本研究中，引入六价钨离子（W6+）来增强电化学动力学，并使用喷雾干燥方法成功制备了W6+掺杂的LVO微球。密度泛函理论 (DFT) 计算表明，W6+ 掺杂后电子电导率的增强和氧晶格的改善可能是由于位于价带最大值之上的中带隙态的发展所致。掺杂的 LVO 显示出优异的电化学性能，包括卓越的倍率性能（10C 下为 288.9 mAh/g）和出色的循环稳定性（6C 下 200 次循环后容量衰减仅为 8.6%），这归因于改善的导电性和 Li+ 嵌入/萃取。此外，我们还使用W6+掺杂的LVO阳极和LiNi0.5Mn1.5O4（LNMO）阴极制作了3.7 V全LIB，以及能量密度为131.8 Wh/kg的锂离子电容器（LIC）。改良的 LVO 和活性炭 (AC)。这项研究展示了 W6+ 掺杂 LVO 在储能应用中的潜力。