Instability of the CuCl2–NH3BH3 mixture followed by TGA and DSC

In the field of ‘hydrogen storage and generation’, ammonia borane NH3BH3 (AB) destabilization can be achieved by adding a metal halide, here copper chloride (CuCl2). Improved dehydrogenation properties can be achieved with a fresh mixture of CuCl2–NH3BH3. Using a systematic approach, we followed the stability of the mixture using thermogravimetric analysis, differential scanning calorimetry and (micro) gas chromatography while it was stored under argon at room temperature over 6 months. The aged samples showed improved dehydrogenation properties compared to pristine AB. However, the performance deteriorated in comparison to the fresh mixture indicating that CuCl2–NH3BH3 evolves over time, decomposing with slow kinetics. This is detrimental in terms of stability during storage, making long-term storage of CuCl2 inconceivable for safety and performance reasons. This is discussed herein.