Material properties and empirical rate equations for hydrogen sorption reactions in 2 LiNH2-1.1 MgH2-0.1 LiBH4-3 wt.% ZrCoH3

Kurzfassung

2 LiNH2-1.1 MgH2-0.1 LiBH4-3 wt.% ZrCoH3 is a solid state hydrogen storage material with a hydrogen storage capacity of up to 5.3 wt.%. As the material shows sufficiently high desorption rates at temperatures below 200 °C, it is used for a prototype solid state hydrogen storage tank with a hydrogencapacity of 2kWhel that is coupled to a high temperature proton exchange membrane fuel cell. In order to design an appropriate prototype reactor, model equations for the rate of hydrogen sorption reactions are required. Therefore in the present study, several material properties, like bulk density and thermodynamic data, are measured. Furthermore, isothermal absorption and desorption experiments are performed in a temperature and pressure range that is in the focus of the coupling system. Using experimental data, two-step model equations have been fitted for the hydrogen absorption and desorption reactions. These empirical model equations are able to capture the experimentally measured reaction rates and can be used for model validation of the design simulations.