Lithium hypophosphite is an underexplored potent reducing agent exhibiting the highest theoretical electrochemical capacity among inorganic hypophosphites (1489 mAh/g) and thus it represents a promising fuel for electrochemical power sources. Despite the existence of two prior reports on its crystal structure, significant knowledge gaps remain regarding its isolation, purification, thermal behavior, and spectroscopic and physicochemical characteristics. The present study reports the preparation and XRD identification of LiH 2 PO 2 . The compound is investigated using infrared and Raman spectroscopy, 31 P-NMR spectroscopy, differential scanning calorimetry, thermogravimetry, and solubility measurements. The interpretation of the infrared and Raman spectra is further supported by DFT simulations. The thermal stability of LiH 2 PO 2 was systematically examined, and phase analysis of the decomposition products identified Li 4 P 2 O 7 and LiPO 3 as primary products. These findings elucidate the decomposition pathway of LiH 2 PO 2 in oxygen-rich environments and suggest its potential application in advanced electrochemical fuel cell applications. • A pioneer study on the structure and properties of the strong eco-friendly reducing agent LiH 2 PO 2 . • Lithium hypophosphite is an ideal compound for advanced electrochemical fuel cells. • Exceptionally high theoretical specific electrochemical capacity of LiH 2 PO 2 (1489 mAh/g), which surpasses all other metal monovalent hypophosphites.
Lozanov et al. (Wed,) studied this question.