Two dimensional holey graphyne: An excellent anode and anchoring material for metal-ion and metal-sulfur batteries

Based on first-principles calculations, the potential of holey graphyne is investigated for battery applications in terms of the storage capacity, volume expansion, diffusion barrier, and metal polysulfides binding. We found substantially higher storage capacities of Li (873 mAh/g) and Na (558 mAh/g) than typical graphite anodes (372 mAh/g for Li and <35 mAh/g for Na) and other carbonaceous materials (450-750 mAh/g for Li and 200-500 mAh/g for Na). The migration barriers of Li and Na turn out to be 0.28 eV and 0.32 eV, respectively, lower than those theoretically reported for commercial anodes TiO2 (0.4-1.0 eV) and silicon (0.6-0.8 eV). Holey graphyne with maximum Li adsorption expands only 0.5%, in contrast to the 10% volume growth in graphite. The lithium and sodium polysulfides and S8 cluster adsorb with moderate binding energies ranging from-0.73 eV to-2.08 eV, which is sufficient to prevent the unintended decomposition of polysulfides. Our findings demonstrate that holey graphyne is a promising anode material for metal-ion batteries and an anchoring material for metal-sulfur batteries to mitigate the shuttle effect.