Releasing 8.0 wt.% H₂ from the LiBH₄-2LiNH₂ Composite within 5 Min under Light Illumination

The absence of safe and efficient hydrogen storage technologies is the major bottleneck for widespread applications of hydrogen energy. Reactive hydride composites with high gravimetric and volumetric hydrogen densities are ideal hydrogen storage materials. However, their traditional dehydrogenation processes normally involving electric-thermal-chemical energy conversion require high operating temperatures and substantial energy inputs to heat the reactor and oven. In this study, using LiBH₄-2LiNH₂ as a model system, that rapid dehydrogenation via a photo-thermal-chemical and/or photo-chemical energy conversion initiated by direct light irradiation is demonstrated and can be fulfilled in the presence of a catalyst and a photothermal agent. The experimental results revealed that the non-thermal effect of UV light plays a critical role in reducing the desorption temperature and enhancing the dehydrogenation kinetics. The collective photothermal and non-thermal effects drove over 8.0 wt.% hydrogen desorption from LiBH₄-2LiNH₂ within 5 min, which is ≈60 times faster than the thermal dehydrogenation process at the same temperature.