新型氨基储氢材料CaCl2的性能研究

研究了工作温度、起始氨压和球磨处理对无水CaCl₂的吸放氨性能的影响. 结果发现, 球磨2h样品在温度20℃和氨压0.55MPa的条件下, 15min内即可完全氨化, 形成CaCl₂(NH₃)₈, 其吸氨量可达55.1wt%, 相当于储氢量9.72wt%. CaCl₂(NH₃)₈在20～300℃的范围内可通过三步反应实现完全脱氨, 脱氨反应受温度和压力控制, 其中6个NH₃分子在常温、常压下即可脱附. 如果与NH₃分解催化剂联用, 可能是一种较好的以NH₃为介质的高容量储氢材料. 进一步研究表明, 较高的工作温度和起始氨压可以提高CaCl₂的吸氨动力学性能, 而球磨时间的增加可以显著降低其放氨工作温度, 提高其放氨动力学性能.

Investigation on Performances of the Novel Ammonia-based Hydrogen Storage Material CaCl2

Ammonia absorption/desorption properties of CaCl₂ and effects of the operation temperature, starting pressure and ball milling treatment were investigated. The post-2h milled sample can be fully ammoniated to form CaCl₂(NH₃)₈ within 15min under 20℃ and 0.55MPa, and the ammonia storage capacity is 55.1wt%, equivalent to be 9.72 wt% of hydrogen. NH₃ can be desorbed from CaCl₂(NH₃)₈ in the temperature range from 20℃ to 300℃ with three stages controlled by temperature and pressure. Six NH₃ molecules can be desorbed at ambient temperature and pressure. Combined with NH₃ decomposition catalyst, CaCl₂ may be one of promising ammonia-based hydrogen storage materials with high capacity. Further investigations indicate that higher operation temperature and starting pressure can improve the ammonia absorption kinetics of CaCl₂, and prolonging ball-milling time can decrease the operation temperature for ammonia desorption of CaCl₂(NH₃)₈ and improve its ammonia desorption kinetics.