An inexpensive, widely available material for 4 wt % reversible hydrogen storage near room temperature

The search for cheap, renewable energy sources to replace fossil fuels has identified hydrogen gas (H₂) as the most promising, particularly for transportation. However, despite intense research efforts to find reliable storage materials, current practical technologies store only 1.3 wt % H ₂ at 270 K, far short of the U.S. DOE targets. We report that hexagonal ice, the ordinary form of ice in snow, may be an efficient hydrogen storage material, achieving 3.8 wt % H₂ storage and 42 g L ^-1 at 150K and that after loading at 150 K, the 3.8 wt % H ₂ can be kept at 270 K and then released upon heating by a few degrees Kelvin. This leads us to propose the ice-fixed melt-triggered (IFMT) strategy for hydrogen storage and utilization with ice as the median.