Computational Design of Porous Organic Frameworks for High-Capacity Hydrogen Storage by Incorporating Lithium Tetrazolide Moieties

We propose to incorporate a lithium tetrazolide group into porous materials for enhancing hydrogen storage capacity. The lithium tetrazolide group is much more stable and polarized than the models made by doping aromatic groups with lithium atoms. More importantly, each of the lithium tetrazolide provides 14 binding sites for hydrogen molecules with modest interaction energies. The advantage of multiple binding sites with modest binding energies is partially demonstrated by constructiong a new porous aromatics framework (PAF-4) with the lithium tertazolide moieties and predictiong its hydrogen uptake using first-principles GCMC simulations. The predicted hydrogen uptake reaches 4.9 wt % at 233 K and 10 MPa, which exceeds the 2010 DOE target of 4.5 wt %.