Quantum chemical calculations of hydrogen storage and battery electrolyte materials

Abstract

The low carbon eco-friendly hydrogen gas fueled vehicles are expected as a solution to the exhaustion of fossil fuel energy reserves and to the prevention of global warming. In order to become hydrogen energy driven society, the research on the production, storage, and application technology of hydrogen energy is most crucial. Nevertheless the suggested potential storage materials such as metal hydride materials, carbon nanostructures and porous materials exhibit the complications of prompt release of hydrogen, and the poor storages capacity of hydrogen less than ~3 wt % are far inferior to the required standard of 5.5 wt % set by the US Department of Energy (DOE) for practical use. As energy storage for the electric drives of the future, a lithium-ion battery is another current isuue. When compared to the nickel-metal hydride technology that has been used to date, lithium-ion technology provides improved power density. Other benefits of lithium-ion batteries include high cycle durability and a longer lifetime, as well as extremely low self-discharge. These are the very reasons why lithium-ion cells are widespread in consumer electronics, and are already used in millions of laptops, mobile phones, and power tools. This research is to propose materials that satisfy the low-cost and high-storage criteria of commercial hydrogen storage and to suggest screening factors in the computational screening process for obtaining promising additives. The abstracts for each subject are as follows.

Hydrogen Storage Materials

First of all, alkali metal amides may exist in solution, the solid phase, and even the gas phase. Based on a theoretical model of a $Li_3N$ system which adsorbs and desorbs two hydrogen molecules, we examine the possible pathways of the $Li_3N+2H_2 ↔ LiNH_2+ 2LiH$ reversible reaction. The dehydrogenation process can be separated into two-step reactions, $Li_2NH+LiH → Li_3N+H_2$ (-9.5 kcal/mol exothermic) and $LiNH_2+LiH → Li_2NH+H_2$ (+0.7 kcal/mol endo...