Calcium chloride substitution in sodium borohydride

• Published in: Journal of solid state chemistry 2020-10, Vol.290 (C), p.121499, Article 121499
• Main Authors: Mattox, Tracy M., Bolek, Georgia, Pham, Anne L., Kunz, Martin, Liu, Yi-Sheng, Fakra, Sirine C., Gordon, Madeleine P., Doran, Andrew, Guo, Jinghua, Urban, Jeffrey J.
• Format: Article
• Language: English
• Subjects: Ball milling; Borohydride; Calcium chloride; Hydrogen storage; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2020.121499

Sodium borohydride (NaBH4) has been a material of interest for many years in developing metal boride complexes and shows a great deal of potential as a hydrogen storage material. Though many have used various additives as catalysts to weaken the bonds within NaBH4 to create a more energetically favorable material, very little is understood about how the borohydride interacts with and changes the additives being incorporated. This work uses ball milling to incorporate calcium chloride (CaCl2) into NaBH4. Using several x-ray techniques, thermogravimetric analysis, and Raman spectroscopy, this study shows not only that the salt diffuses into NaBH4 but describes how the borohydride changes the additive itself. In gaining a stronger understanding of what happens to the additives needed to weaken the borohydride bonds, future researchers may have an easier time selecting the appropriate additive to create a borohydride complex that will meet their needs. Powder x-ray diffraction peak of NaBH4 at ~6.2° in NaBH4–CaCl2 mixtures containing 0%, 10%, 20%, and 40% CaCl2 at 25 ​°C (left) and 400 ​°C (right). [Display omitted]