Hydrogen Storage Alloys

Magnesium and magnesium alloys have been intensively studied for decades as hydrogen storage materials. Magnesium could form MgH2 with hydrogen. MgH2 has a very high hydrogen storage capacity, but has obvious disadvantages in both thermodynamics and kinetics. Researchers have attempted to optimize the thermodynamic and kinetic properties of MgH2 via various techniques, e.g. via alloying, using catalytic additives, deforming, and nanotechnology, and so forth.

As for the alloying route, investigated alloys include Mg-Ni, Cu-Mg, Mg-Nd, Ce-Mg, and La-Mg, and so forth.

In TCS Mg-based Alloys Database (TCMG) starting with version 6 (TCMG6), eight binaries (Ce-H, Cu-H, La-Zn, H-La, H-Mg, H‑Nd, H-Ni, and H-Zn) and five ternaries (Ce-H-Mg, Cu-H-Mg, H-La-Mg, H-Mg-Nd, and Mg-H-Ni) are modeled for application to hydrogen storage. This is in to the relevant systems already modeled in versions TCMG5 and earlier.

Cu-Mg-H

Calculated Cu-H-Mg isothermal sections at 573 K at different pressures

Figure 1: Calculated Cu-H-Mg isothermal sections at 573 K at different pressures [2020aChe].

Calculated hydrogen dissolution pressure of a Cu-Mg2 single-phase alloy

Figure 2: Calculated hydrogen dissolution pressure of a Cu-Mg2 single-phase alloy [2020aChe].

Calculated hydrogen dissolution pressure of two Cu-Mg alloys

Figure 3: Calculated hydrogen dissolution pressure of two Cu-Mg alloys [2020aChe].

Mg-H-Ni

Calculated isothermal section of Mg-H-Ni at 574 K and 3.47 bar

Figure 4: Calculated isothermal section of Mg-H-Ni at 574 K and 3.47 bar [2020Che].

Calculated vapor pressure of Mg2NiH4 in the Mg-H-Ni ternary system

Figure 5: Calculated vapor pressure of Mg2NiH4 in the Mg-H-Ni ternary system [2020bChe].

References

[2020aChe] H.L. Chen, Modeling of Cu-H-Mg in TCMG6, Thermo‑Calc Software (2020).

[2020bChe] H.L. Chen, Refinement of Mg-H-Ni in TCMG6, Thermo‑Calc Software (2020).