Hydrogen absorption/desorption behaviors over a quaternary Mg-Ca-Li-N-H system

Hydrogen storage in a quaternary Mg-Ca-Li-N-H system has been investigated by XRD, FT-IR, TPD and PCI. Results showed that hydrogen desorption occurred at temperature about 50 °C, and peaked at ∼178 °C under a heating rate of 2 °C min−1. The reversibility of hydrogen storage was observed and the maximum hydrogen storage capacity of about 2.7 wt.% was reached at 220 °C and 75 atm. However, the plateau pressure for hydrogen desorption is relatively low (∼0.3 atm). Structural identifications reveal that a new phase with tetragonal structure positioned at 31.8° and 51.3° of XRD peaks was generated during hydrogen absorption/desorption.