Development of a gaseous and solid-state hybrid system for stationary hydrogen energy storage

Hydrogen can serve as a carrier to store renewable energy in large scale. However, hydrogen storage still remains a challenge in the current stage. It is difficult to meet the technical requirements applying the conventional storage of compressed gaseous hydrogen in high-pressure tanks or the solid-state storage of hydrogen in suitable materials. In the present work, a gaseous and solid-state (G-S) hybrid hydrogen storage system with a low working pressure below 5 MPa for a 10 kW hydrogen energy storage experiment platform is developed and validated. A Ti–Mn type hydrogen storage alloy with an effective hydrogen capacity of 1.7 wt% was prepared for the G-S hybrid hydrogen storage system. The G-S hybrid hydrogen storage tank has a high volumetric hydrogen storage density of 40.07 kg H2 m−3 and stores hydrogen under pressure below 5 MPa. It can readily release enough hydrogen at a temperature as low as −15 °C when the FC system is not fully activated and hot water is not available. The energy storage efficiency of this G-S hybrid hydrogen storage system is calculated to be 86.4%–95.9% when it is combined with an FC system. This work provides a method on how to design a G-S hydrogen storage system based on practical demands and demonstrates that the G-S hybrid hydrogen storage is a promising method for stationary hydrogen storage application.