Achieving solid-state room temperature dehydrogenation from sodium borohydride composited with glycolic acid

Sodium borohydride (NaBH4) has long been regarded as a cost-effective hydrogen storage material with a theoretical hydrogen storage capacity of 10.6 wt%. However, its practical application is hindered by thermodynamic stability, and traditional hydrogen production from NaBH4 required excess water, which lowered its volumetric and gravimetric capacities. In this study, for the first time, solid-state glycolic acid (GA) was used to destabilize NaBH4 for producing hydrogen. According to the results, NaBH4-GA started releasing hydrogen rapidly from room temperature and more than 3.6 wt% hydrogen was produced below 100 ℃ with efficient hydrogen utilization rate of 95 %. Moreover, NaBH4-GA composites maintained solid-state through the entire dehydrogenation process with high volumetric capacity above 39 g H2 L−1. Through the evolution of bonding structures and composition in NaBH4-GA composites, the dehydrogenation process was further confirmed as similar to the hydrolysis process of NaBH4, but with no liquid appearing. This chemical process “solid-state hydrolysis” may offer potential application and novel insights in low-temperature solid-state hydrogen storage using NaBH4. [Display omitted] •Solid-state NaBH4-GA composites were prepared successfully by easy hand-milling.•The onset hydrogen release temperature of NaBH4 was significantly decreased to room temperature.•The reaction process in NaBH4-GA composites was similar to the hydrolysis of NaBH4 but in solid state.