Joan Santiago Cortinez Osorio MSc. in Materials Engineering student Enhanced Hydrogen Storage in Mg thin Flakes with dispersed Ni Nanoparticles prepared by High Energy Ball Milling. CIDEMAT University of Antioquia Colombia TableOf Contents Introduction Materials and Methods Results Conclusions TableOf Contents 3 4 Magnesium hydride (MgH2) Lightweight, reversible and abundant on Earth’s crust Theoretical storage capacity (7.67 wt.%) Sluggish kinetics and thermodynamic stability Solutions for H2 storage Gas Liquid (LH2 - LHCs) Solid Lower risk in transportation and higher gravimetric capacities. Introduction |solid state storage Sorption / Desorption >350 °C Ea 146 kJ/mol Hirscher et al. Materials for hydrogen-based energy storage – past, recent progress and future outlook. Journal of Alloys and Compounds. 2020 5 Hirscher et al. Materials for hydrogen-based energy storage – past, recent progress and future outlook. Journal of Alloys and Compounds. 2020 Introduction | Mg modifications Metal-oxide catalysts Morphological modifications Alloying elements and additives Nanoparticles or nanostructures They Improve kinetics or thermodynamics But decrease storage capacity An approach that involves various modifications is required Introduction Materials and Methods Results TableOf Contents 6 Conclusions c.p Mg (95%) Two step method of Surfactant Assisted – High Energy Ball Milling Materials and methods | Synthesis 7 • BPR 40:1 • 1400 rpm • ZrO2 balls, 1 mm • BPR 60:1 • 1400 rpm • ZrO2 balls, 3 mm Mg Ni NPs Blending 28.3 ± 16.1 nm DeformationComminution Hexane + Stearic Acid 5 wt.%Ni 15 wt.%Ni Materials and Methods | Characterization 8 Absorption / Desorption tests (350°C) Differential Scanning Calorimetry X-Ray Diffraction SEM-EDX Introduction Materials and Methods Results Conclusions TableOf Contents 9 10 Results | Mg thin flakes 1st step 2nd step Starting crystallite size 197.9 nm Cortinez et al. Production of Mg Thin Flakes with Enhanced Hydrogen Storage Performance. International Journal of Hydrogen Energy. 2024 11 Results | Mg thin flakes 1st step 2nd step Refined crystallite size 17.8 nm Cortinez et al. Production of Mg Thin Flakes with Enhanced Hydrogen Storage Performance. International Journal of Hydrogen Energy. 2024 12 Results | Mg thin flakes 4.6 w.t% in 6 min 4.4 wt.% in 15 min Improved kinetics (94% less time) and capacity (increase in 25%) Cortinez et al. Production of Mg Thin Flakes with Enhanced Hydrogen Storage Performance. International Journal of Hydrogen Energy. 2024 Homogeneous distribution through the dry blending method Results | Mg with Ni decoration 13 Mg-5%Ni Mg-15%Ni Improved kinetics (50% of the time) but decreased capacity (9%) 14 Results | Kinetics test at 350°C, 20 bar 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 0 1 2 3 4 5 H y d ro g e n u p ta k e ( w t. % ) Time (min) Mg thin flakes Mg-5%Ni Mg-15%Ni 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 -5 -4 -3 -2 -1 0 Mg-15%Ni Mg-5%Ni Mg thin flakes H y d ro g e n r e le a s e ( w t. % ) Time (min) 4.2 wt.% in 3 min 0 1 2 3 4 5 6 7 8 9 10 -6 -5 -4 -3 -2 -1 0 H y d ro g e n r e le a s e ( w t. % ) Time (min) Mg-15%Ni, hydrogenated at 20 bar Mg-15%Ni, hydrogenated at 10 bar Mg-5%Ni, hydrogenated at 20 bar Mg-5%Ni, hydrogenated at 10 bar 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 0 1 2 3 4 5 6 H y d ro g e n u p ta k e ( w t. % ) Time (min) Mg-15%Ni, 20 bar Mg-15%Ni, 10 bar Mg-5%Ni, 20 bar Mg-5%Ni, 10 bar 15 Results | Kinetics at 350°C, 10 bar Lower pressures resulted in higher capacities but slower kinetics due a to a change in sorption mechanism. Tien et al. Mechanism of hydrogen capacity dependence on the hydrogenation temperature. Scr Mater. 2010 16 Results | Mg with Ni decoration 200 220 240 260 280 300 320 340 360 380 400 -10 -8 -6 -4 -2 0 MgH2 Mg + 2H2 333,79°C 377,59°C H e a t fl u x ( W /g ) Temperature (°C) Mg thin flakes Mg-5%Ni Mg-15%Ni 332,23°C Exo LT- Mg 2 NiH 4 HT-Mg 2 NiH 4 Mg2NiH4 Mg2Ni + 2H2 Mg2Ni promotes desorption reaction This was later confirmed by XRD analysis Decrease in operation temperature Hydrogen sorption at 350°C promotes Mg – Ni reaction to form the complex hydride 17 Results | Mg with Ni decoration 20 30 40 50 60 70 80 ■ψ ♠♠♠♠♠ ♠ ♠ ♠ Mg-15%Ni Mg-5%NiIn te n s it y ( a .u ) 2θ (°) Mg thin flakes Mg♠ ψMgO ♠ψ ♠♠♠♠♠ ♠ ♠ ♠ ♠ Ni■ ■ ■ψ ♠♠♠♠♠ ♠ ♠ ♠ ♠■ 20 30 40 50 60 70 80 ▼ ▼▼▼ ▼ ▼ In te n s it y ( a .u ) 2θ (°) Mg-15%Ni (hydrided) Mg-5%Ni (hydrided) Mg thin flakes (hydrided) ♦ ♦ ♦ ♦ ♠ ♠♠ ♠ ψ ♦ ♦ ♦ ♦♦ Mg MgOψ♠♦ MgH2 ♦ ♦ ♦ ♦ ♠ ψ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦♦♦♦♦♦ ♦ ♦ ♠ ψ ♦ ♦ ♦ ♦♦ψ ♦♦ ♦ ♦ Mg2NiH4▼ ▼▼ Oxygen content (EDX) below 5 wt.% A fter a b c d Mg-15%NiMg-5%Ni B efo re 18 Results | Mg with Ni decoration Preserved morphology after 5 cycles 19 Results | Mg with Ni decoration Higher Ni content agglomerated after sorption/desorption tests M g- 1 5 % N i M g- 5 % N i 20 Results | Mg with Ni decoration 416 ± 127 nm Cycling could lead to finer particles Introduction Materials and Methods Results Conclusions TableOf Contents 21 Conclusions 22 A two step ball milling method led to Mg thin flakes (thickness <300 nm) and improved hydrogen storage capacity 5 wt.%Nickel decoration improved sorption/desorption process in 50% of the time with a decrease of 9% in capacity The formation of Mg2NiH4 after activation process led to improved dehydrogenation kinetics 23 Thanks for your attention Diapositiva 1 Diapositiva 2 Diapositiva 3 Diapositiva 4 Diapositiva 5 Diapositiva 6 Diapositiva 7 Diapositiva 8 Diapositiva 9 Diapositiva 10 Diapositiva 11 Diapositiva 12 Diapositiva 13 Diapositiva 14 Diapositiva 15 Diapositiva 16 Diapositiva 17 Diapositiva 18 Diapositiva 19 Diapositiva 20 Diapositiva 21 Diapositiva 22 Diapositiva 23