The authors regret that in the original article, the scale bars in Fig. 4b and 5a were incorrect. The authors also regret errors in the orientation of the atomic planes in Fig. 6e. Additionally, the range of the X-axis in Fig. 9a was twice as large as the correct value, and two numbers in Table 3 were incorrectly shown as 12 and 2.95 instead of the correct values, 0.2 and 6.6. These unintentional errors do not affect any other data or the conclusions of the manuscript. The correct Fig. 4 6, 9 and Table 3 are as shown here. (Figure presented) (Table presented) (Figure presented). The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

The hydride phase of Ti₅₀V₂₀Cr₃₀ alloy cast with 4 wt% of 7Zr+10Ni has been investigated. Pressure composition desorption isotherms were measured at 150 °C and 200 °C. These isotherms revealed same desorption of 1.5 wt% at 150 °C and 200 °C. The evolution of the crystal structure upon dehydrogenation was investigated by in-situ neutron diffraction. A sample was fully deuterated at room temperature under 2000 kPa pressure. Afterwards, the sample was heated from 120 °C to 266 °C under vacuum and neutron diffraction patterns were recorded as a function of temperature. It was found that the alloy started to desorb very quickly at 200 °C. The amount of fcc phase was monitored using the relative intensity of the fcc phase compared to a standard. At 266 °C only 10% hydride phase was seen, which was confirmed by X-ray diffraction. Besides the fcc phase, a minor aluminum phase due to the heating element was also observed in all patterns. Thermal expansion coefficient of Al and fcc phase were calculated. Using the aluminum peaks as reference, it was found that deuterium occupancy reflect the phase abundance of the fcc deuteride.

Magnesium hydride has been studied extensively for applications as a hydrogen storage material owing to the favourable cost and high gravimetric and volumetric hydrogen densities. However, its high enthalpy of decomposition necessitates high working temperatures for hydrogen desorption while the slow rates for some processes such as hydrogen diffusion through the bulk create challenges for large-scale implementation. The present paper reviews fundamentals of the Mg–H system and looks at the recent advances in the optimisation of magnesium hydride as a hydrogen storage material through the use of catalytic additives, incorporation of defects and an understanding of the rate-limiting processes during absorption and desorption.