Vanadium oxide and vanadium sulfide/carbon hybrid electrodes by electrospinning for lithium and sodium ion batteries (HEROES-4-Li-Na-batteries)

用于锂和钠离子电池的静电纺丝氧化钒和硫化钒/碳混合电极（HEROES-4-Li-Na-电池）

• 批准号: 452180147
• 负责人: Professor Dr. Volker Presser
• 金额: --
• 依托单位: Leibniz-Institut für Neue Materialien gGmbH (INM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/452180147?language=en
• 关键词: Vanadium; oxide; vanadium; sulfide; carbon

Our project will synthesize vanadium oxide/carbon and vanadium sulfide/carbon hybrid fibers through the combination of electrospinning and thermal treatments, and investigate their properties as electrodes for Li- and Na-ion batteries. By modifying key parameters of the hybrid material, we will establish detailed structure/property correlations. This knowledge is of high importance to establish design guidelines and synthesis strategies for future generation Li- and Na-ion battery electrodes.Most work on Li- and Na-ion batteries designs a certain Faradaic electrode material, admix a carbon conductive additive (to ensure electrical conductivity), and consolidate both components onto a current collector by use of a binder (often polymer-based). Such composites limit the understanding of the intrinsic parameters governing (and limiting) the electrochemical performance of the active components of the electrodes. Also, a more intimate, nanoscale interface between Li- or Na-ion host materials and the conductive phase can only be realized by nanoscale hybridization instead of mechanical mixing.Our work will employ electrospinning to design hybrid fibers where we obtain right away binder-free electrodes. We can use a “one-pot” synthesis approach to obtain vanadium oxide / carbon hybrids that can be converted in vanadium sulfide / carbon fibers upon H2S treatment. This approach enables a high level of nanoscale interaction between the phase where ion storage accomplishes charge storage and conductive carbon, which is superior to mechanical mixing of the two components. To achieve conductive and electrochemically stable Li- and Na-ion battery electrodes, we aim to (1) study the effect of conductive carbon content, as well as carbon character (i.e., porosity, pore size); (2) vanadium oxide/sulfide crystal structure, and (3) fiber architecture on the hybrid morphology and electrochemical properties. This will be done by combining extensive materials characterization with standard and in situ electrochemical testing.The work includes systematic analysis of the electrode materials with X-ray diffraction, electron microscopy, energy-dispersive X-ray spectroscopy, Raman and IR spectroscopy, and thermal analysis. In collaboration, we will also quantify ion diffusion und chemical states via nuclear magnetic resonance spectroscopy and complement chemical analysis via X-ray photoelectron spectroscopy. Electrochemical tests will include basic electrochemistry in organic electrolyte, rate handling, and longevity benchmarking. To further identify limiting aspects, we will employ in situ measurements to quantify structural changes by in situ X-ray diffraction, in situ electrochemical dilatometry, and electrochemical quartz crystal microbalance measurements and by use of impedance spectroscopy and galvanostatic intermittent titration technique. Structural post mortem analyses will further contribute to identify degradation mechanisms.

我们的项目将通过静电纺丝和热处理相结合合成氧化钒/碳和硫化钒/碳混合纤维，并研究它们作为锂离子和钠离子电池电极的性能。通过修改杂化材料的关键参数，我们将建立详细的结构/性能相关性。这些知识对于制定未来一代锂离子和钠离子电池电极的设计指南和合成策略非常重要。大多数有关锂离子和钠离子电池的工作都设计某种法拉第电极材料，混合碳导电添加剂（以确保导电性），并使用粘合剂（通常基于聚合物）将两种成分固结到集电器上。这种复合材料限制了对控制（和限制）电极活性成分电化学性能的内在参数的理解。此外，锂离子或钠离子主体材料与导电相之间更紧密的纳米级界面只能通过纳米级杂化而不是机械混合来实现。我们的工作将采用静电纺丝来设计混合纤维，从而立即获得无粘合剂电极。我们可以使用“一锅法”合成方法来获得氧化钒/碳杂化物，这些杂化物可以通过 H2S 处理转化为硫化钒/碳纤维。这种方法使得离子存储完成电荷存储的相与导电碳之间能够实现高水平的纳米级相互作用，这优于两种组分的机械混合。为了获得导电且电化学稳定的锂离子和钠离子电池电极，我们的目标是（1）研究导电碳含量以及碳特性（即孔隙率、孔径）的影响； （2）氧化钒/硫化物晶体结构，以及（3）纤维结构对混合形态和电化学性能的影响。这将通过将广泛的材料表征与标准和原位电化学测试相结合来完成。这项工作包括使用 X 射线衍射、电子显微镜、能量色散 X 射线光谱、拉曼和红外光谱以及热分析对电极材料进行系统分析。在合作中，我们还将通过核磁共振波谱量化离子扩散和化学态，并通过 X 射线光电子能谱补充化学分析。电化学测试将包括有机电解质中的基本电化学、速率处理和寿命基准测试。为了进一步确定限制因素，我们将通过原位 X 射线衍射、原位电化学膨胀测量和电化学石英晶体微天平测量以及使用阻抗谱和恒电流间歇滴定技术，采用原位测量来量化结构变化。结构尸检分析将进一步有助于确定降解机制。