[论文解读] Effect of Niobium Doping on the Crystal Structure and Hydrogen Sorption Properties of TiFe: Combined Synchrotron X-ray Diffraction and Extended X-ray Absorption Fine Structure Study

Abhishek Banerjee, Stefano Deledda+1 more|arXiv (Cornell University)|Jan 13, 2026

Hydrogen Storage and Materials被引用 0

一句话总结

研究通过同步辐射X射线衍射和EXAFS研究Nb掺杂的TiFe合金，以理解结构变化和氢吸附改进，显示在不损失储氢容量的情况下提高了活化和动力学，且与 Nb 在二次Ti含相中的占位相关。

ABSTRACT

TiFe alloys are attractive compounds for solid-state stationary hydrogen storage. They can absorb hydrogen gas reversibly at near ambient temperatures and practical pressures with high volumetric capacities surpassing that of cryogenically liquified H2. The main drawback of TiFe-based storage systems is a costly activation procedure required due to the formation of oxide surface layer, which hinders hydrogen diffusion into the bulk. Doping the alloy with various additives is known to improve hydrogen diffusion softening the conditions of the activation procedure. Hydrogen sorption properties of the modified alloys have been the focus of most studies whereas less attention has been dedicated to the fundamental understanding of the effects of hydrogen sorption on the alloys' structure. The latter, however, is an important information in the knowledge-guided design of novel materials. In this work, we investigated effects of Nb-doping on crystallographic structure of TiFe metal-alloy compounds and their hydrogen sorption properties. TiFe samples with two different Nb stoichiometries were synthesized using arc-melting (AM) and characterised with synchrotron powder X-ray diffraction (SR-PXRD) and extended X-ray absorption fine structure (EXAFS) analysis. Overall, H2 absorption measurements (at 50 +/- 2 degrees C and 40 +/- 2 bar), have shown that doping of TiFe with Nb can improve matrix activation and kinetics of hydrogen sorption without compromising the overall storage capacities. Refinement of SR-PXRD and EXAFS data showed significant Nb occupancy in secondary Ti phases, which improved the hydrogenation properties of the alloys.

研究动机与目标

• 了解Nb掺杂如何影响TiFe基合金的晶体结构。
• 确定Nb对氢吸附性能和活化行为的影响。
• 通过SR-PXRD和EXAFS识别与改进的动力学和保持储氢容量相关的结构特征。

提出的方法

• 通过电弧熔炼制备两种Nb计量比的TiFe合金。
• 利用同步辐射粉末X射线衍射（SR-PXRD）表征结构。
• 用扩展X射线吸收精细结构（EXAFS）分析局部结构。
• 在50 ± 2 °C和40 ± 2 bar进行氢吸收测量，以评估活化和动力学。
• 对SR-PXRD和EXAFS数据进行 refinement，以确定Nb在二次Ti相中的占位。

实验结果

研究问题

• RQ1 Nb掺杂是否以影响氢扩散路径的方式改变TiFe合金的晶体结构？
• RQ2 Nb掺入如何影响活化过程和氢吸附动力学？
• RQ3 Nb在二次Ti相中的占位对TiFe的氢存储性能有何作用？
• RQ4 Nb掺杂能否在提升动力学的同时保持或提高存储容量？

主要发现

• Nb掺杂提高了TiFe合金基体的活化和氢吸附动力学。
• 尽管添加Nb，氢存储容量得以保持。
• 精修表明Nb在二次含Ti相中有显著占位，与改进的氢化性能相关。
• 研究了两种Nb化学计量比以阐明Nb在结构中的分布作用。
• 在不影响整体存储性能的前提下实现了活化和动力学方面的收益。