Mechano-chemical synthesis of manganese borohydride (Mn(BH4)2) and inverse cubic spinel (Li2MnCl4) in the (nLiBH4 + MnCl2) (n = 1, 2, 3, 5, 9 and 23) mixtures and their dehydrogenation behavior

The Effects of Additives on the Dehydrogenation of Amorphous Manganese Borohydride and Its Crystalline Form after Solvent Filtration/Extraction

“…The Solely the NaCl-type diffraction peaks accompanied by a weak, singular NaBH 4 peak can be seen in the BM (2NaBH 4 + MnCl 2 ) XRD pattern (bottom), as already reported by Varin et al [11]. The center XRD pattern in Figure 8, which belongs to the same sample after solvent filtration/extraction, is very similar to the XRD pattern of the BM (2LiBH 4 + MnCl 2 ) mixture containing the crystalline c-Mn(BH 4)2 hydride co-existing with a LiCl salt [3][4][5][6][7][8][9][10] (a top XRD pattern). The NaCl-type salt was effectively filtered during the filtration stage, and therefore, no NaCl-type diffraction peaks are discernible in Figure 8 in the XRD pattern for the solvent extracted sample (center).…”

“…When the 1 h ball milled (2NaBH 4 + MnCl 2 ) sample was used, we observed identical results (the XRD patterns are not shown here). Figure 9 shows MS (gas desorption spectra) of a (H 2 + B 2 H 6 ) mixture (Figure 9a) and the corresponding TGA and DSC thermal decomposition curves (Figure 9b) for the (2NaBH 4 + MnCl 2 ) sample ball milled for 1 h (Q TR = 72.8 kJ/g), and then extracted at 42 • C. The intensity ratio of the MS H 2 /B 2 H 6 signal up to 200 • C equals 1626, which is much higher than 948 for a ball milled (2NaBH 4 + MnCl 2 ) counterpart [11], and also much higher than the ratio of 200-600 for a ball milled (2LiBH 4 + MnCl 2 ) [8]. The second extracted sample, which was investigated by MS, exhibited the MS ratio H 2 /B 2 H 6 = 1546, which confirms a very low quantity of released B 2 H 6 from the extracted crystalline c-Mn(BH 4 ) 2 .…”

“…Changing the angular positions of one or two strong NdFeB magnets and altering the number of hard steel balls in a milling vial can control the milling energy in the magneto ball mill Uni-Ball-Mill 5 [3,[7][8][9][10]13]. As recently reported by Parviz et al [13], the quantity of milling energy, Q TR(R) per unit mass·hour (kJ/gh), which was injected into and stored in a milled powder for each particular milling mode with a fixed ball-to-powder mass ratio, R, in the magneto ball mill Uni-Ball-Mill 5, can be calculated via a semi-empirical method.…”

“…Experimentally obtained lattice spacings, d (hkl) , for crystalline c-Mn(BH 4 ) 2 , that was solvent extracted from the 0.5 and 1 h ball milled (2NaBH 4 + MnCl 2 ) samples, are listed in Table 2. For comparison, the d (hkl) values calculated from synchrotron radiation as reported by Varin et al [8], and those obtained from selected area electron diffraction pattern (SAEDP) [10], are also included for comparison. The agreement between the d (hkl) values in this work and those reported by Varin et al [8] and Shirani Bidabadi [10] is very good.…”

“…For comparison, the d (hkl) values calculated from synchrotron radiation as reported by Varin et al [8], and those obtained from selected area electron diffraction pattern (SAEDP) [10], are also included for comparison. The agreement between the d (hkl) values in this work and those reported by Varin et al [8] and Shirani Bidabadi [10] is very good. Since different precursors and methods for the Mn(BH 4 ) 2 synthesis were used in the present work than those reported by Varin et al [8] and Shirani Bidabadi [10], some small differences in the lattice spacings are expected.…”