A boron-11 NMR study of the stability of the alkaline aqueous solution of sodium borohydride that is both an indirect fuel and a direct fuel for low-temperature fuel cells - Université de Montpellier
Article Dans Une Revue International Journal of Hydrogen Energy Année : 2022

A boron-11 NMR study of the stability of the alkaline aqueous solution of sodium borohydride that is both an indirect fuel and a direct fuel for low-temperature fuel cells

Résumé

Alkaline aqueous solution of sodium borohydride NaBH4 (denoted SB-fuel) is an indirect fuel when it is used to generate H2 by hydrolysis, with the as-generated H2 feeding a fuel cell, and it is a direct fuel when it is an anodic fuel of a direct fuel cell. However, SB-fuel suffers from a major drawback: NaBH4 spontaneously hydrolyzes. Our study falls within this context. We studied the instability, at the NMR scale and over 12 weeks, of a series of SB-fuels (initial NaBH4 concentration from 3.65 to 31.22 wt%, NaOH concentration from 1 to 16 M, and temperature between -15 and 60 degrees C) to find the conditions at which SB-fuel can be stored for weeks in relative safety. We found that SB-fuel with a NaOH concentration of >= 8 M is relatively stable under cold conditions (-15 and 4 degrees C). In these conditions, NaBH4 is not prevented from hydrolyzing, but the reaction is significantly mitigated. Otherwise, our study highlights the gaps in our understanding of the SB-fuel, emphasizes SB-fuel is a new concept of fuel (it should not be seen as any current fuel) , points out the challenges for attaining higher technology readiness levels.

Domaines

Chimie

Dates et versions

hal-03712785 , version 1 (04-07-2022)

Identifiants

Citer

Damien Alligier, Eddy Petit, Umit Demirci. A boron-11 NMR study of the stability of the alkaline aqueous solution of sodium borohydride that is both an indirect fuel and a direct fuel for low-temperature fuel cells. International Journal of Hydrogen Energy, 2022, 47 (55), pp.23310-23315. ⟨10.1016/j.ijhydene.2022.05.119⟩. ⟨hal-03712785⟩
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