Xie Hui, Liang Tianxiao, Cui Tian, Feng Xiaolei, Song Hao, Li Da, Tian Fubo, Redfern Simon A T, Pickard Chris J, Duan Defang
State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P. R. China.
Department of Physics and Electronic Engineering, Hebei Normal University for Nationalities, Chengde, 067000, China.
Phys Chem Chem Phys. 2022 Jun 1;24(21):13033-13039. doi: 10.1039/d2cp00298a.
KSiH exhibits 4.1 wt% experimental hydrogen storage capacity and shows reversibility under moderate conditions, which provides fresh impetus to the search for other complex hydrides in the K-Si-H system. Here, we reproduce the stable 3̄ phase of KSiH and uncover two denser phases, space groups 3̄1 and 6 at ambient pressure, by means of first-principles structure searches. We note that 3̄1-KSiH has a high hydrogen content of 5.4 wt% and a volumetric density of 88.3 g L. Further calculations suggest a favorable dehydrogenation temperature of -20.1/55.8 °C with decomposition into KSi + K + H. The higher hydrogen density and appropriate dehydrogenation temperature indicate that KSiH is a promising hydrogen storage material, and our results provide helpful and clear guidance for further experimental studies. We found three further potential hydrogen storage materials stable at high pressure: KSiH, KSiH and KSiH. These results suggest the need for further investigations into hydrogen storage materials among such ternary hydrides at high pressure.
KSiH具有4.1 wt%的实验储氢容量，并在中等条件下表现出可逆性，这为在K-Si-H体系中寻找其他复杂氢化物提供了新的动力。在此，我们通过第一性原理结构搜索重现了KSiH的稳定3̄相，并在常压下发现了另外两个密度更高的相，空间群分别为3̄1和6。我们注意到，3̄1-KSiH具有5.4 wt%的高氢含量和88.3 g/L的体积密度。进一步的计算表明，其有利的脱氢温度为-20.1/55.8 °C，分解产物为KSi + K + H。较高的氢密度和合适的脱氢温度表明KSiH是一种很有前景的储氢材料，我们的结果为进一步的实验研究提供了有益且明确的指导。我们还发现了另外三种在高压下稳定的潜在储氢材料：KSiH、KSiH和KSiH。这些结果表明有必要对这类三元氢化物在高压下的储氢材料进行进一步研究。
