The consequence of silicon additive in isothermal decomposition of hydrides LiH, NaH, CaH2 and TiH2

The study focuses on hydrogen desorption characteristics of lithium hydride (LiH), sodium hydride (NaH), calcium hydride (CaH2), and titanium hydride (TiH2) which permits a possible path regarding challenging goals of US DOE standards. This research reported the consequences of enrichment in hydrogen uptake 7.02 wt% in lithium hydride, 7.71 wt% in sodium hydride, 5.91 wt% in calcium hydride, and 5.00 wt% in titanium hydride using silicon as an additive when evaluated with the help of volumetric technique. The ball milling process with silicon additive for LiH, NaH, CaH2, and TiH2 shows depletion in dehydrogenation temperatures 523 K, 453 K, 488 K, and 463 K respectively. Similarly, the reduction in the activation energies reported due to ball milling process with silicon additive are 37 kJ/mol for lithium hydride, 42 kJ/mol for sodium hydride, 56 kJ/mol for calcium hydride and 45 kJ/mol for titanium hydride compared with crystalline powder samples of the respective materials. The outcome of Fourier-transform infrared spectroscopy of milled hydride samples after decomposition intimate rapid decrease in transmittance intensities due to hydrogen release because of the destabilization effect caused by silicon additive. The porosity and sponginess in high-resolution Transmission electron microscopy images after dehydrogenation reveals the hydrogen desorption from the sample materials. •TG-DTA for isothermal decomposition of LiH, NaH, CaH2 & TiH2 with 10% Si additive.•Reduction in dehydrogenation temperature & activation energy values by Si additive.•Characterization of samples by FTIR & TEM spectroscopy methods for validation.