Superior Destabilization Effects of MnF2 over MnCl2 in the Decomposition of LiBH4

A 3LiBH(4)/MnF2 composite was prepared by me. chanically milling a mixture of LiBH4 and MnF2. The decomposition properties of the 3LiBH(4)/MnF2 composite were investigated and compared with those of the 3LiBH(4)/MnCl2 composite. Differing from the case for the 3LiBH(4)/MnCl2 composite where only cation substitution occurs, both the cation substitution of Mn2+ for Li+ and the anion substitution of F- for H- occur in the 3LiBH(4)/MnF2 composite. Moreover, compared to the 3LiBH(4)/MnCl2 composite, the 3LiBH(4)/MnF2 composite has a lower decomposition temperature, a higher purity of evolved hydrogen, and faster decomposition kinetics. These results suggest that MnF2 has superior destabilization effects over MnCl2 in the decomposition of LiBH4, which can be attributed to the reduced stability of B-H bonds by partial anion substitution of the F- for the H-.