Superior Hydrogen Sorption Kinetics of Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> High-Entropy Alloy
oleh: Jianwei Zhang, Pengcheng Li, Gang Huang, Weiguang Zhang, Jutao Hu, Haiyan Xiao, Jian Zheng, Xiaosong Zhou, Xia Xiang, Jingxia Yu, Huahai Shen, Sean Li, Xiaotao Zu
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2021-03-01 |
Deskripsi
High entropy alloys (HEAs) are composed of multiple main metal elements and have attracted wide attention in various fields. In this study, a novel Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> HEA was synthesized and its hydrogenation properties were studied, including sorption thermodynamics and hydrogen absorption/desorption kinetics. The maximum hydrogen absorption capacity was 1.5 H/atom at 573 K. X-ray diffraction (XRD) analysis indicated that the crystal structure of Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> HEA transformed from body-centered cubic (BCC) to body-centered tetragonal (BCT) with increasing hydrogen content, and to face-centered cubic (FCC) after hydrogen absorption to saturation. As a multi-principal element alloy, the Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> HEA possesses unique hydrogen absorption characteristics. The hydrogen absorption platform pressure rises gradually with the increase of the hydrogen absorption amount, which is caused by multiple kinds of BCT intermediate hydrides with consecutively increasing c/a. The full hydrogen absorption of the Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> HEA was completed in almost 50 s, which is faster than that of the reported hydrogen storage alloys in the literature. The experimental results demonstrate that the Ti<sub>0.20</sub>Zr<sub>0.20</sub>Hf<sub>0.20</sub>Nb<sub>0.40</sub> HEA has excellent kinetic properties, unique thermodynamic hydrogen absorption performance, as well as a low plateau pressure at room temperature.