College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China.
Phys Chem Chem Phys. 2018 Dec 12;20(48):30304-30311. doi: 10.1039/c8cp05846f.
Motived by the recent experimental fabrication of two-dimensional boron hydride (BH) sheets (Nishino et al., J. Am. Chem. Soc. 2017, 139, 13761), we explore the feasibility of pristine and Li doped BH sheets as a hydrogen storage medium within the framework of density functional theory. BH shows an unexpected high affinity to Li with a binding energy of -2.38 eV in comparison to other alkali and alkaline earth metals (Na, K, Ca, Mg and Al), much larger than its bulk cohesive energy (-1.63 eV). Energy barriers of Li diffusion on BH are also determined to be around 1.12 eV, showing both high dynamic and thermodynamic stability without the issue of cluster formation. Moreover, Li decorated BH is expected to achieve a high theoretical gravimetric density of 11.57 wt% with an average H2 adsorption energy of -0.17 eV, holding great potential in massive hydrogen storage. In addition to the storage, thermodynamic analysis on the desorption behaviors of H2 molecules is performed via N-P-T diagram, which demonstrates that most of the H2 molecules (8.30 wt%) could be released at 3 atm/100 °C. Thus, the Li-decorated BH sheets are expected to be applied as an efficient medium for hydrogen storage under ambient conditions.
受最近二维硼氢化物 (BH) 片的实验制备的启发（Nishino 等人，J. Am. Chem. Soc. 2017, 139, 13761），我们在密度泛函理论的框架内探索了原始和 Li 掺杂的 BH 片作为储氢介质的可行性。与其他碱金属和碱土金属（Na、K、Ca、Mg 和 Al）相比，BH 对 Li 具有出人意料的高亲和力，结合能为-2.38 eV，远大于其体相结合能（-1.63 eV）。还确定了 Li 在 BH 上扩散的能垒约为 1.12 eV，表现出高动力学和热力学稳定性，而不会出现团簇形成的问题。此外，Li 修饰的 BH 有望实现高达 11.57 wt%的理论重量密度，平均 H2 吸附能为-0.17 eV，在大规模储氢方面具有巨大的潜力。除了存储之外，还通过 N-P-T 图对 H2 分子的解吸行为进行了热力学分析，结果表明，大多数 H2 分子（8.30 wt%）可以在 3 atm/100°C 下释放。因此，Li 修饰的 BH 片有望在环境条件下作为高效储氢介质得到应用。
