Hydrogen Storage Materials for Remote Area Power Supply, Movable Power Supply and Automotive Applications

Air pollution, global warming and the imminent exhaustion of fossil fuels drive people to use renewable energy to replace hydrocarbon fuels. Hydrogen is one of the most promising energy carriers to harvest the intermittent renewable energy. There are basically three types of applications: stationary Remote Area Power Supply (RAPS), Movable Power Supply (MPS) and automotive vehicles. The aim of this research is to develop suitable hydrogen storage materials for these three applications. In this study, vanadium-based alloy was designed to meet the requirements of RAPS and MPS applications. The effects of particle size and mechanical treatment on the hydrogen storage properties of vanadium-based alloy have been investigated. Briefly, the 5 mm vanadium-based alloy has 2 wt% of usable hydrogen capacity under 20-50 °C and 0.2-2 MPa, which is 40% higher than commercial AB5 alloys and fully satisfies the capacity needs of RAPS and MPS systems. The alloy provides a rapid hydrogen supply rate which is 9 times faster than the requirement. The alloy possesses an excellent cycle life up to 500 cycles with a 90 % of capacity retention. Carbon nitride tubes were selected as the hydrogen storage materials for automotive applications because of their high theoretical hydrogen capacity (5.45 wt%) which reaches 2025 US DOE target. Currently, compressive hydrogen is used in fuel cell vehicles with 70 MPa of pressure, leading to uncertain hazards and extra energy consumption. Carbon nitride tubes may potentially reduce the pressure from 70 MPa to several MPa without a significant capacity loss. The highest hydrogen capacity achieved in this work is 0.62 wt% at 3.6 MPa. This value corresponds to a surface area of 148.69 m2/g which is so far the highest record in N-rich carbon nitride tubes. The hydrogen capacity is predicted as 2.62 wt% at 10 MPa. Carbon nitride tubes have a swift recharging speed (2-3 minutes), which is competitive to the refuelling of petrol. The special thermal dynamics enables carbon nitride tubes to absorb and desorb hydrogen at ambient conditions. Besides the material study, a novel and time-saving approach was developed to precisely measure the hydrogen capacity at various absorption/desorption temperatures