Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
Center for Theoretical Sciences and Center for Quantum Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
Sci Rep. 2017 Jul 10;7(1):4966. doi: 10.1038/s41598-017-05202-6.
Accurate prediction of the electronic and hydrogen storage properties of linear carbon chains (C ) and Li-terminated linear carbon chains (LiC ), with n carbon atoms (n = 5-10), has been very challenging for traditional electronic structure methods, due to the presence of strong static correlation effects. To meet the challenge, we study these properties using our newly developed thermally-assisted-occupation density functional theory (TAO-DFT), a very efficient electronic structure method for the study of large systems with strong static correlation effects. Owing to the alteration of the reactivity of C and LiC with n, odd-even oscillations in their electronic properties are found. In contrast to C , the binding energies of H molecules on LiC are in (or close to) the ideal binding energy range (about 20 to 40 kJ/mol per H). In addition, the H gravimetric storage capacities of LiC are in the range of 10.7 to 17.9 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, LiC can be high-capacity hydrogen storage materials that can uptake and release hydrogen at temperatures well above the easily achieved temperature of liquid nitrogen.
准确预测线性碳链（C n ）和锂终止线性碳链（LiC n ）的电子和储氢性质一直是传统电子结构方法面临的巨大挑战，因为它们存在强烈的静态相关效应。为了应对这一挑战，我们使用新开发的热辅助占据密度泛函理论（TAO-DFT）来研究这些性质，这是一种用于研究具有强烈静态相关效应的大型系统的非常有效的电子结构方法。由于 C n 和 LiC n 的反应性随 n 的变化，它们的电子性质呈现出奇偶振荡。与 C n 不同，H 分子在 LiC n 上的结合能处于（或接近）理想的结合能范围（每个 H 约 20 到 40 kJ/mol）。此外，LiC n 的 H 重量储氢容量在 10.7 到 17.9 wt%之间，满足美国能源部（USDOE）的最终目标 7.5 wt%。基于我们的结果，LiC n 可以是高容量储氢材料，可以在远高于容易达到的液氮温度下吸收和释放氢气。
