Investigation on LiBH(4)-CaH(2) composite and its potential for thermal energy storage

The LiBH(4)/CaH(2) composite are firstly studied as Concentrating Solar Power Thermal Storage Material. The LiBH(4)/CaH(2) composite according to the stoichiometric ratio are synthesized by high-energy ball milling method. The kinetics, thermodynamics and cycling stability of LiBH(4)/CaH(2) composite are investigated by XRD (X-ray diffraction), DSC (Differential scanning calorimeter) and TEM (Transmission electron microscope). The reaction enthalpy of LiBH(4)/CaH(2) composite is almost 60 kJ/mol H(2) and equilibrium pressure is 0.482 MPa at 450 °C. The thermal storage density of LiBH(4)/CaH(2) composite is 3504.6 kJ/kg. XRD results show that the main phase after dehydrogenation is LiH and CaB(6). The existence of TiCl(3) and NbF(5) can effectively enhance the cycling perfomance of LiBH(4)/CaH(2) composite, with 6–7 wt% hydrogen capacity after 10 cycles. The high thermal storage density, high working temperature and low equilibrium pressure make LiBH(4)/CaH(2) composite a potential thermal storage material.