Reactivity characterization tests of selected solid-state hydrogen storage materials

Solid-state hydrogen storage materials such as complex metal hydrides, chemical hydrides, and adsorbents are promising alternatives to the use of compressed hydrogen gas or liquefied hydrogen for on-board vehicular applications. However, acceptance by the general public to the use of hydrogen, in any of its on-board storage forms, as an energy carrier in the transportation sector requires assurance that this application is safe and poses no additional risks above the current risk acceptance criteria associated with use of gasoline/diesel in the transportation sector. This research discusses the results of an experimental program covering materials reactivity tests, dust cloud combustion characterization tests, mechanical impact sensitivity tests, and material/hot surface contact tests. These tests were performed to identify safety-critical characteristics of selected solid-state hydrogen storage materials. Based upon the results of those tests, risk mitigation methods were proposed to eliminate or mitigate the identified risks. The effectiveness of the proposed risk mitigation methods was also examined. The insights gained from the experimental program could be useful to ongoing research efforts aimed at identifying the best hydrogen storage materials from a safety standpoint as well as supporting current and future risk-informed hydrogen safety standards such as NFPA-2, ISO, and IEC.