SGER: Chemical Frustration and the Design of New Hydrogen Storage Material

CBET-0844720 Zhang The hydrogen storage challenge, and equally compelling issues in large-scale hydrogen generation, impedes the broad commercialization of this otherwise compelling energy carrier. Not only do existing storage technologies fail to meet requirements in capacity, cost and reversibility, but there are no clear optimization paths from known systems to fully practical on-board storage systems. In this research, the PI will perform an intense two-year theoretical materials design search, using powerful first-principles methods and exploiting several new concepts in hydrogen-substrate interaction, with the goal of discovering one or more new families of hydrogen sorbents. It will exploit the concept of electronic frustration, wherein intrinsic or geometrically-induced electron deficiency generates novel multi-center electronic configurations, unusual charge-transfer states, or anomalously large local fields that enhance hydrogen binding. Over the course of the two-year research effort, these calculations will identify targets for further investigation and optimization of hydrogen capacity and synthesizability, through studies of convex-hull phase stability and kinetic barriers. Boron-hydrogen molecules have a surprisingly rich and highly unconventional chemistry arising from an intrinsic electronic frustration associated with having just three valence electrons in the s-p shell. The PI will investigate several novel boron-based frameworks with build-in sites for multicenter hydrogen binding and will use doping to modulate the overall charge state of the framework to attain maximal framework stability, optimal hydrogen binding energetics, kinetics and reversibility within thermodynamic constraints on relative phase stability. Electronic frustration will also be induced geometrically, by means of topological and topographical constraints that prevent systems with well-known atomic constituents from attaining their traditional ground state structures. Topological barriers and topographical constraints will help induce novel electronic states with prospects to demonstrate new modes of binding to close-shell species such as molecular hydrogen. A solution to the hydrogen storage challenge would have a transformative impact throughout society, from environment issues to energy security, national security and transportation. The proposed research will educate one graduate student in interdisciplinary computational materials research. Student training in electronic structure theory relies upon a solid grounding in condensed matter theory, yet also requires important concepts from chemistry and materials science and naturally develops in students a strong familiarity with large-scale high-performance computation on massively parallel computers. This integrated multidisciplinary training on an application-oriented project will broaden the student's knowledge and experience and thereby prepare them for careers that span disciplines. Students will have opportunity to communicate their results both at research venues and to the general public.