静电纺丝法制备自支撑Zn2VO4/N-CNFs复合中间层及电化学性能研究

    Preparation and Electrochemical Performance of Zn2VO4/N-CNFs Free-Standing Composite Interlayer by Electrospinning Technology

    • 摘要: 应用静电纺丝技术设计了一种具有3D 网状结构的Zn、V 双金属化合物-氮掺杂碳纳米纤维自支撑中间层(Zn2VO4/N-CNFs),被用于锂硫电池。结果表明,吡啶氮和吡咯氮能与锂离子发生强的相互作用,Zn2VO4 对多硫化锂有极强的吸附和催化效果。碳纳米纤维网络捕捉多硫化锂的同时还可以提供长程电子传导路径,在促进电子转移的同时又能存储电解液,提供了电化学反应空间。Zn2VO4/N-CNFs 中间层发挥了对多硫化锂从捕捉到促进转化的双功能作用。因此,采用Zn2VO4/N-CNFs 中间层的锂硫电池在0.2 C 下的初始放电比容量为796.1 mAh·g-1,循环100 圈后仍可保持727.2 mAh·g-1 的容量, 容量保持率为91.3%。在1.0 C 时, 电池的初始容量为593.4 mAh·g-1, 循环1000 圈后仍保有353.3 mAh·g-1 的容量,每圈的容量衰减仅为0.0024%。

       

      Abstract: Zn, V bimetallic compound-carbon nanofibers free-standing interlayer (Zn2VO4/N-CNFs) with 3D mesh structure was designed for lithium sulfur (Li-S) batteries by electrospinning technology. The results show that the pyridine nitrogen and pyrrole nitrogen can strongly interact with lithium-ion, Zn2VO4 has a strong adsorption and catalytic effect on lithium polysulfide. The multi-layer carbon nanofiber network can also provide long-range electron conduction paths while capturing polysulfides, which can promote electron transfer and store electrolyte at the same time, providing the space for electrochemical reaction. The Zn2VO4/N-CNFs interlayer can play the bifunctional role of adsorbing and facilitating the transformation of lithium polysulfide. The battery with Zn2VO4/N-CNFs interlayer can deliver an initial discharge capacity of 796.1 mAh·g-1 at 0.2 C, and keep at 727.2 mAh·g-1 after 100 cycles with the capacity retention rate of 91.3%.In addition, the battery delivers an initial capacity of 593.4 mAh·g -1 at 1.0 C, and retains at 353.3 mAh·g -1 after 1000 cycles with corresponding capacity attenuation of 0.0024% per cycle.

       

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