Effects of graphite addition and air exposure on ball-milled Mg-Al alloys for hydrogen storage

Autor(es)

Niyomsoan, S. ^[1] ; Leiva, D. R. ^[2] ; Silva, R. A. ^[2] ; Chanchetti, L. F. ^{[2, 3]} ; Shahid, R. N. ^{[4, 5]} ; Scudino, S. ^[4] ; Gargarella, P. ^[2] ; Botta, W. J. ^[2]

Afiliação do(s) autor(es)

^[1] Burapha Univ, Fac Gems, Integrated & Innovat Jewelry Mat Res Unit, Chanthaburi 22170 - Thailand

^[2] Fed Univ Sao Carlos UFSCar, Mat Engn Dept, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Fed Sao Carlos, Postgrad Program Mat Sci & Engn PPGCEM, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] IFW Dresden, Inst Complex Mat, Helmholzstr 20, D-01069 Dresden - Germany

^[5] Pakistan Inst Engn & Appl Sci, Dept Met & Mat Engn, Islamabad - Pakistan

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; v. 44, n. 41, p. 23257-23266, AUG 30 2019.
• Citações Web of Science: 1

Resumo

Magnesium hydride (MgH2) is a promising candidate as a hydrogen storage material. However, its hydrogenation kinetics and thermodynamic stability still have room for improvement. Alloying Mg with Al has been shown to reduce the heat of hydrogenation and improve air resistance, whereas graphite helps accelerating hydrogenation kinetics in pure Mg. In this study, the effects of simultaneous Al alloying and graphite addition on the kinetics and air-exposure resistance were investigated on the Mg60Al40 system. The alloys were pulverized through high-energy ball milling (hereinafter HEBM). We tested different conditions of milling energy, added graphite contents, and air exposure times. Structural characterization was conducted via X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). H-2 absorption and desorption properties were obtained through volumetry in a Sieverts-type apparatus and Differential Scanning Calorimetry (DSC). The desorption activation energies were calculated using DSC curves through Kissinger analysis. Mg60Al40 with 10 wt% graphite addition showed fast activation kinetics, even after 2 years of air exposure. Graphite addition provided a catalytic effect on ball-milled Mg-Al alloys by improving both absorption and desorption kinetics and lowering the activation energy for desorption from 189 kJ/mol to 134 kJ/mol. The fast kinetics, reduced heat of reaction, and improved air resistance of these materials make them interesting candidates for potential application in hydride-based hydrogen storage tanks. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 13/05987-8 - Processamento e caracterização de ligas metálicas amorfas, metaestáveis e nano-estruturadas
• Beneficiário: Claudio Shyinti Kiminami
• Linha de fomento: Auxílio à Pesquisa - Temático