Sustainable NaAlH4 production from recycled automotive Al alloy

Abstract

To reduce the carbon footprint associated with the production of hydrogen storage materials and to reduce their cost, we pursue the possibility of obtaining high-quality hydride-based materials from industrial metals waste. In particular, in this manuscript, we propose a method for obtaining high-quality NaAlH₄, starting from the Al-based automotive recycled alloy DIN-GDAlSi10Mg(Cu). The hydrogen storage properties of the material obtained by ball milling NaH and DIN-GDAlSi10Mg(Cu) under a hydrogen atmosphere were comprehensively explored via a broad range of experimental techniques, e.g. volumetric analysis, ex situ X-ray diffraction (XRD), in situ synchrotron radiation powder X-ray diffraction (SR-PXD), scanning electron microscopy (SEM), and differential thermal analysis (DTA). These investigations show that NaAlH₄ was successfully synthesized and that its properties are comparable with those of high-purity commercial NaAlH₄.