Merger of Energetic Affinity and Optimal Geometry to Boost Hydrogen Storage in Porous Materials: Ab initio based Multiscale Simulations
Master of Science
Hydrogen is an ideal alternative fuel for various applications such as automobiles and portable devices because it is lightweight, abundant, and its oxidation product (water) is environmentally benign. However, its utilization is impeded by the lack of a safe and efficient storage device. Herein, we investigate and propose a new building block approach for an exhaustive search of optimal hydrogen uptakes in a series of low density boron nitride (BN) nanoarchitectures via an extensive 3868 multiscale simulations based on ab initio results. By probing various geometries, temperatures, pressures, and doping ratios, our results demonstrate a maximum uptake of 8.65 wt% at 300K, the highest hydrogen uptake on sorbents at room temperature without doping. Next, we investigate the Li+ doping of the nanoarchitectures exhibiting a set of optimal combinations of gravimetric and volumetric uptakes, surpassing the US DOE targets. Our findings suggest that the non-intuitive merger of energetic affinity and optimal geometry in BN building blocks overcomes the intrinsic limitations of sorbent materials, putting hybrid BN nanoarchitectures on equal footing with hydrides while demonstrating a superior capacity-kinetics-thermodynamics balance. Finally, we propose a novel methodology to improve the stability and accuracy of the fitting of empirical force- field parameters against ab initio data. Overall, the proposed building block approach, combined with the novel concepts and strategies for exhaustive search of optimum structure-property relationships in adsorption, opens up an entirely new phase space for making efficient high performance gas storage materials.
Hydrogen Storage; Multiscale Simulation