• PhD Position: Absorption/desorption of hydrogen in MAX phases, MXenes and their Mg-based nanocomposites

    Supervision: Dr. Antoine GUITTON (antoine.guitton[at]univ-lorraine.fr) Prof. Thierry GROSDIDIER
    Location: LEM3, Université de Metz, France

    Financial support: CNRS Grant (starting October 1th, 2020 ; 3 years duration).
    Keywords : Max Phases, MXenes, hydrogen storage, Microstructural analysis, Electron microscopy.

    Solid state storage of hydrogen in low pressure tanks (ground transportation purposes) can take advantage of the reversible transformation of metal into metastable metal-hydrides within an appropriate temperature range. Such storage systems using Mg hydrides is safe and lightweight but exhibit a low charge and discharge kinetic even at relatively high temperatures (>200°C). To overcome these limitations, new alloys and microstructural modifications are explored. Understanding the effects of structural defects and catalysts on the physical mechanisms involved in the hydride nucleation and growth reaction is however needed and difficult: hydrides are unstable under vacuum.

    Mn+1AXn phases (n = 1 to 3, M being a transition metal, A an A-group element and X = N or C) are nanolaminated ternary compounds–synthesized by powder metallurgy from cheap and widely available elements. Because of their anisotropic layered structure, the MAX-phases can theoretically store large amounts of hydrogen in solid solution. MAX phases are also precursors for MXenes, one of the largest families of two-dimensional materials. In the form of stacks, these materials have demonstrated remarkable performance as (co-) catalysts for key fuel cell reactions and are promising for hydrogen storage.

    In this thesis, we will explore the influence of microstructural defects (dislocations, grain boundaries, heterophasic interfaces) on the fundamental mechanisms of hydrogen storage in MAX phases, MXenes and their Mg-based nanocomposites. This thesis is part of a collaboration project between several laboratories – LEM3 (Metz, France), Institut Pprime (Poitiers, France), IC2MP (Poitiers, France), GPM (Rouen, France), Beijing Jiaotong University (China) and I2CNER (Japan) –

    More details HERE


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