Enhanced dehydrogenation kinetic properties and hydrogen storage reversibility of LiBH_4 confined in activated charcoal

活性炭限域提高硼氢化锂放氢动力学和可逆储氢性能（英文）

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 k J/mol, which leads to the eminent enhancement of dehydrogenation kinetics of LiBH4.

通过熔融浸渗法将LiBH_4限域于多孔活性炭中,并研究浸渗限域对LiBH_4储氢性能的影响。氮气吸附结果表明,熔融浸渗方法能够有效将LiBH_4限域于活性炭中。该方法既能够保持活性炭骨架结构完整,又能确保限域的效果。放氢结果表明,活性炭限域LiBH_4在190°C开始放氢,该起始放氢温度比纯LiBH_4低160°C,并且在400°C时放氢容量达到13.6%。放氢后样品在6 MPa氢压和350°C下再吸氢,可逆储氢容量达到6%,而在相同条件下,纯LiBH_4几乎没有可逆储氢容量。质谱分析结果表明,放氢过程中没有乙硼烷和其他杂质气体放出。活性炭限域的LiBH_4放氢表观活化能由156.0 k J/mol降低到121.1 k J/mol,使LiBH_4放氢动力学性能得到显著改善。