Enhanced dehydrogenation kinetic properties and hydrogen storage reversibility of LiBH4 confined in activated charcoal
(1. State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China;
2. State Key Laboratory of Advanced Transmission Technology, Global Energy Interconnection Research Institute, State Grid Corporation of China, Beijing 102209, China)
2. State Key Laboratory of Advanced Transmission Technology, Global Energy Interconnection Research Institute, State Grid Corporation of China, Beijing 102209, China)
Abstract: LiBH4 was confined into activated charcoal (AC) by melt infiltration method (MI), and its effects on the hydrogen sorption properties were investigated. The N2 adsorption results reveal that melt infiltration method can effectively incorporated LiBH4 into AC. It can maintain the structural integrity of the scaffold and ensure the confinement effect. The nano-confined LiBH4/AC starts to release hydrogen at around 190 °C, which is 160 °C lower than that of pure LiBH4, and reaches a hydrogen desorption capacity of 13.6% at 400 °C. When rehydrogenated under the condition of 6 MPa H2 and 350 °C, it has a reversible hydrogen storage capacity of 6%, while pure LiBH4 shows almost no reversible hydrogen storage capacity under the same condition. Mass spectrometry analysis (MS) results suggest that no diborane or other impurity gases are released in the decomposition process. The apparent activation energy of dehydrogenation of LiBH4 after confinement into AC decreases from 156.0 to 121.1 kJ/mol, which leads to the eminent enhancement of dehydrogenation kinetics of LiBH4.
Key words: hydrogen storage materials; hydrogen storage properties; lithium borohydride; activated charcoal; melt infiltration