Low-temperature hydrogen release through LiAlH4 and NH4F react in Et2O

• Published in: International journal of hydrogen energy 2020-03, Vol.45 (15), p.8774-8782
• Main Authors: Wang, Xiaolian, Chen, Yungui, Kong, Qingquan, Feng, Wei, Li, Zhenghang, Wu, Yuchen, Liu, Yonghui, Wu, Chaoling
• Format: Article
• Language: English
• Subjects: Et2O; Hydrogen release; Hydrogen storage; LiAlH4; NH4F
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.01.102

The application of hydrogen energy urgently requires a high-capacity hydrogen storage technology that can release hydrogen at low temperature. The composite of LiAlH4 and NH4F has a hydrogen storage capacity of up to 8.06 wt%, but the release of hydrogen requires a reaction temperature of about 170 °C, and the reaction is difficult to control. In this work, the reaction between LiAlH4 and NH4F is proposed to be carried out in diethyl ether to improve its hydrogen release performance. It exhibits good hydrogen release performance over a wide temperature range of −40–25 °C, and the hydrogen release capacity at −40 °C, −20 °C, 0 °C and 25 °C can reach 4.41 wt%, 6.79 wt%, 6.85 wt% and 7.78 wt%, respectively. The activation energy of the reaction is 38.41 kJ mol−1, which is much lower than many previously reported catalytic hydrolysis systems that can release hydrogen at room temperature. Our study demonstrates a high-performance hydrogen storage system with very low operating temperature, which may lay the foundation for the development of practical mobile/portable hydrogen source in the north and the Arctic. •Catalyst-free LiAlH4–NH4F–Et2O exhibits high H2 yield of >4.41 wt% at −40 °C.•The hydrogen release kinetics is affected by the reaction temperature.•The new compound HAlNH·0.25Et2O is further confirmed.•The reaction mechanism is determined by comprehensive methods.