Effect of microwave irradiation on the hydrogen desorption properties of MgH2/LiBH4 composite

The effect of microwave irradiation on the hydrogen desorption properties of MgH2 + xLiBH4 (x = 0-30 wt%) composite was systematically investigated. The results show that the composite can be heated rapidly with the addition of LiBH4 by microwave heating which brings about the fast dehydrogenation of MgH2. The heating rate of the samples depends on the content of LiBH4 and the microwave power, because LiBH4 acts as a microwave absorber above 107 °C. Isothermal kinetic results showed that the amount of hydrogen released from MgH2 + 10 wt% LiBH4 under microwave is 5 times more than that of under conventional heating at 300 °C in 30 min. After five cycles of hydrogen sorption at 350 °C, the sample can be heated even more rapidly by microwave heating. These results demonstrate that the microwave heating is an effective technology to improve the hydrogen desorption kinetics of the MgH2/LiBH4 composite with high energy efficiency. Causes for the improved microwave heating were discussed and a potential mechanism was proposed.