Thermodynamic and kinetic properties of calcium hydride

Calcium hydride with aluminium for thermochemical energy storage applications

“…Balakrishnan et al recently determined the decomposition thermodynamics of molten CaH 2 to be Δ H des = 216 ± 10 kJ mol −1 H 2 and Δ S des = 177 ± 9 J K −1 mol −1 H 2 , giving T des(1bar) of 947 ± 65 °C. 18 This is 524 °C higher than the first step of decomposition of CaH 2 + 2Al and 447 °C higher than the second step.…”

“…17 Recently, Balakrishnan et al updated the thermodynamics and kinetics of pure calcium hydride at high temperature in the molten and solid state. 18 Calcium hydride is an appealing material because of its high energy storage density (5131 kJ kg −1 ), but the decomposition temperature of above 900 °C and the sluggish reaction kinetics hinder the utilisation of pure CaH 2 for technological applications. 18 In the past decades, several studies looked at the thermodynamic destabilisation of CaH 2 with additives to reduce the operating temperature and enhance the reaction kinetics.…”

“…18 Calcium hydride is an appealing material because of its high energy storage density (5131 kJ kg −1 ), but the decomposition temperature of above 900 °C and the sluggish reaction kinetics hinder the utilisation of pure CaH 2 for technological applications. 18 In the past decades, several studies looked at the thermodynamic destabilisation of CaH 2 with additives to reduce the operating temperature and enhance the reaction kinetics. 19 The CaH 2 –11Zn system was determined to operate at 1 bar of H 2 and ∼600 °C, where cyclic reversibility of the first reaction step over 10 cycles resulted in the loss of 0.02 wt% sorption of H 2 .…”