Room-temperature hydrogen storage via two-dimensional potential well in mesoporous graphene oxide

Abstract

Hydrogen is an excellent energy carrier free of carbon dioxide emission, but safe and efficient storage of hydrogen has been a bottleneck for the commercial use of hydrogen as a fuel. Here, we present a strategy based on simple thermodynamic principles that the density of a gas residing in a potential well increases exponentially relative to the ambient gas by the corresponding Boltzmann factor. This mechanism allows for enormously enhanced H2 storage in the form of delocalized gas permeating throughout the void space of a material, in contrast to conventional storage localized to specific adsorption sites. We create mesoporous graphene oxide that provides a two-dimensional potential well and efficient hydrogen diffusion pathways. The gravimetric storage density measured with quartz-crystal microbalance reaches 4.65wt% reproducibly at a modest pressure of 40atm at room temperature. Our work demonstrates the attainability of the long-standing goal of room-temperature hydrogen storage.