Excellent low-temperature dehydrogenation performance and reversibility of 0.55LiBH4-0.45Mg(BH4)2 composite catalyzed by few-layer Ti2C

Abstract

The 0.55LiBH4-0.45Mg(BH4)2 (LMBH) eutectic composite is promising for solid-state hydrogen storage, as it exhibits a high hydrogen capacity and a very low initial dehydrogenation temperature. However, its main hydrogen release steps still require higher temperatures. In the present study, few-layer Ti2C has been synthesized and utilized as catalysts in the LMBH. Compositing LMBH with varying amounts of Ti2C (10, 20, 30, and 40 wt%) results in low initial dehydrogenation temperatures (164–110 °C), fast desorption rates and high hydrogen capacities (7.5–10.5 wt%) at a low temperature of 260 °C. The LMBH-30Ti2C composite yields 6.5 wt% H2 even at as low as 200 °C. Additionally, the LMBH-30Ti2C composite could reversibly store 3.5 wt% H2 during the second to fourth dehydrogenation cycles without degradation. The outstanding hydrogen storage performance could be attributed to decomposition driven by reactions between high-valence Ti ions and LMBH, the in-situ formation of the active metal Ti catalyst, and the prevention of aggregation in the Ti2C-doped LMBH.