Yang Guang, Wang Huanhuan, Zhang Bowei, Foo Shini, Ma Mingbo, Cao Xun, Liu Jilei, Ni Shibing, Srinivasan Madhavi, Huang Yizhong
School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore.
Nanoscale. 2019 May 16;11(19):9556-9562. doi: 10.1039/c9nr01953g.
Research on VS4 is lagging due to the difficulty in its tailored synthesis. Herein, unique architecture design of one-dimensional VS4 nanowires anchored on reduced graphene oxide is demonstrated via a facile solvothermal synthesis. Different amounts of reduced graphene oxide with VS4 are synthesized and compared regarding their rate capability and cycling stability. Among them, VS4 nanowires@15 wt% reduced graphene oxide present the best electrochemical performance. The superior performance is attributed to the optimal amount of reduced graphene oxide and one-dimensional VS4 nanowires based on (i) the large surface area that could accommodate volume changes, (ii) enhanced accessibility of the electrolyte, and (iii) improvement in electrical conductivity. In addition, kinetic parameters derived from electrochemical impedance spectroscopy spectra and sweep rate dependent cyclic voltammetry curves such as charge transfer resistances and Li+ ion apparent diffusion coefficients both support this claim. The diffusion coefficient is calculated to be 1.694 × 10-12 cm2 s-1 for VS4 nanowires/15 wt% reduced graphene oxide, highest among all samples.
由于VS4的定制合成存在困难，其研究进展滞后。在此，通过简便的溶剂热合成法展示了锚定在还原氧化石墨烯上的一维VS4纳米线的独特结构设计。合成了不同含量还原氧化石墨烯与VS4的复合材料，并比较了它们的倍率性能和循环稳定性。其中，VS4纳米线@15 wt%还原氧化石墨烯表现出最佳的电化学性能。这种优异的性能归因于还原氧化石墨烯的最佳含量以及一维VS4纳米线，基于以下几点：（i）能够适应体积变化的大表面积，（ii）电解质可及性的增强，以及（iii）电导率的提高。此外，从电化学阻抗谱和扫描速率依赖的循环伏安曲线得出的动力学参数，如电荷转移电阻和Li+离子表观扩散系数，都支持这一观点。VS4纳米线/15 wt%还原氧化石墨烯的扩散系数计算为1.694×10-12 cm2 s-1，是所有样品中最高的。
