Mg-based Alloy Hydrogen Storage Kinetics
Solution Overview
Problem
Current hydrogen storage and transportation technologies face safety issues due to high compression pressures, heavy steel cylinders, or expensive cryogenic temperatures, and existing solid-state materials like pure Mg have slow absorption and desorption kinetics, making them impractical for commercial use.
Innovation Solution
Development of Mg-based alloys with controlled additions of Cu, Ni, Si, and Na, formed using conventional casting techniques, which create eutectic and hypoeutectic compositions that enhance hydrogen storage kinetics and can be produced economically, offering improved absorption and desorption rates without the need for exotic or expensive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pure Mg is used for hydrogen storage, then hydrogen storage capacity is achieved (7.6 mass %), but absorption and desorption kinetics are too slow for practical use
Solution Approach 1:
The patent creates composite Mg-based alloys combining Mg with eutectic-forming elements (Al, Ag, Au, Ba, Bi, Ca, Ce, Cu, Eu, Ga, Gd, Ge, Hg, La, Ni, Pb, Sb, Si, Sm, Sn, Sr, Th, Tl, Y, Yb, Zn) to form dual-phase structures. These composite materials provide both high hydrogen storage capacity from the Mg phase and improved kinetics from the eutectic intermetallic phases, resolving the contradiction between storage capacity and reaction kinetics.
Solution Approach 2:
The patent changes the compositional parameters by precisely controlling the content of eutectic-forming elements to achieve specific eutectic compositions. By adjusting alloying element content and controlling solidification parameters, the patent optimizes the microstructure to balance hydrogen storage capacity and absorption/desorption kinetics, transforming pure Mg into optimized Mg-based alloys with tailored performance.
2Ease of manufacture
If conventional casting techniques are used, then manufacturing cost is reduced and ease of manufacture is improved, but alloy composition control precision may be compromised
Solution Approach 1:
The patent establishes specific parameter ranges for eutectic-forming element content (e.g., Al: 3-15 mass%, Si: 0.1-3 mass%, Cu: 0.1-5 mass%, Ni: 0.1-5 mass%, Na: 0.01-0.5 mass%) that can be achieved through conventional casting. By defining these compositional parameters, the patent enables precise alloy composition control using standard manufacturing techniques, resolving the contradiction between ease of manufacture and composition precision.
3Reliability
If expensive and complex formation technologies like ball-milling or vapour deposition are used, then alloy microstructure can be refined and hydrogen storage performance improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent utilizes the eutectic phase transition during solidification to naturally refine the alloy microstructure. By controlling the eutectic composition and solidification parameters, the patent achieves fine dual-phase microstructures without requiring complex post-processing techniques like ball-milling or vapour deposition. This resolves the contradiction between hydrogen storage performance and device complexity by leveraging inherent phase transition behavior.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Mg-based alloys provide high-performance hydrogen storage characteristics comparable to or exceeding those of ball-milled materials, with tailored compositions for specific applications, reducing weight and cost while ensuring safety and practicality for commercial use.
Implementation Method 1
additions of one or more eutectic-forming elements, such as Al, Ag, Au, Ba, Bi, Ca, Ce, Cu, Eu, Ga, Gd, Ge, Hg, La, Ni, Pb, Sb, Si, Sm, Sn, Sr, Th, Tl, Y, Yb and Zn
Implementation Method 2
Mg is capable of storing hydrogen as magnesium hydride (MgH2) at 7.6 mass %
Implementation Method 3
storing hydrogen gas via a chemical reaction with a suitable solid such that the gas is effectively occluded into the solid
Implementation Method 4
the kinetics of the absorption and desorption reactions for pure Mg are too slow
Data Source
AI summary
A range of alloys of Mg and at least one of Cu, Si, Ni and Na alloys that is particularly suitable for hydrogen storage applications. The alloys of the invention are formed into binary and ternary systems. The alloys are essentially hypoeutectic with respect to their Cu and Ni contents, where one or both of these elements are present, but range from hypoeutectic through to hypereutectic with respect to their Si content when that element is also present. The terms hypoeutectic and hypereutectic do not apply to Na if it is added to the alloy. The alloy compositions disclosed provide high performance alloys with regard to their hydrogen storage and kinetic characteristics. They are also able to be formed using conventional casting techniques which are far cheaper and more amenable to commercial use than the alternative ball-milling and rapid solidification techniques which are much more expensive and complex. Each of the individual binary Mg-E systems, where E=Cu, Ni or Si, forms a eutectic comprising of Mg metal and a corresponding MgxEy intermetallic phase.