Materials Engineering and Scale-up of Fluid Phase Chemical Hydrogen Storage for Automotive Applications

Among candidates for chemical hydrogen storage in proton exchange membrane (PEM) fuel cell automotive applications, ammonia borane (AB, NH₃BH₃) is considered to be one of the most promising materials due to its high hydrogen content of 14–16 wt % below 200 °C. Motivated by our previous study based on a model slurry of AB in silicone oil, optimized with an ultrasonic process, we proceeded to scale-up to liter size batches with solid loadings up to 50 wt % (ca. 8 wt % H₂) with viscosities less than 1000 cP at 25 °C. The use of a non-ionic surfactant, Triton X-15, shows significant promise in controlling the level of foaming produced during the thermal dehydrogenation of the AB. Stable homogeneous slurry of high solid loading was shown as a viable hydrogen delivery source, based on the new and efficient processing techniques and the ability to adequately control the foaming