Quasi-2D liquid cell for high density hydrogen storage

Abstract

Hydrogen has been recognized as a future energy carrier that may allow a gradual transformation from a fossil fuel-based economy to a hydrogen economy. One of main obstacles to implement hydrogen economy is efficient storage of hydrogen. Up to present, none of proposed storage methods completely satisfy all department of energy (DOE) target criteria with gravimetric capacity ~5.5wt% and loss rate 0.1 (g/h)/kg for hydrogen storage yet. Here we demonstrate high density of hydrogen nano-bubble (HNB) up to ~3.4±0.18wt% can be efficiently generated and stored via an electron radiolysis assisted abstraction reaction (RAAR) in an encapsulated quasi-2D water reservoir containing organic molecules. The RAAR is a reaction between radiolytic water species and the surface groups of organic molecules. In our system, the long term stability of HNB comes from supersaturation of hydrogen molecules controllable by the electron dose rate and concentration of the organic molecule. The best gravimetric capacity and loss rate in our experiment are ~3.4±0.18wt% and 0.18(g/h)/kg, respectively, in 25°C and at 1bar which fall closely to the DOE targets. A TEM equipped with a continuous flow holder with a quasi-2D water reservoir is utilized for in-situ generation and storage of HNB. The regeneration time for HNB formation is in the order of a few ten seconds. This process can be linked with the microbial electrolysis cell technology that converts hydrogen from wastewater containing abundant organics.