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SUMMARY

Kononiuk O. P. Hydrogen absorption-desorption and hydrolysis properties of

new Mg–IMC and Mg–IMC–C hydride composites. – Qualifying scientific work on

manuscript rights.

Dissertation for obtaining the scientific degree of Doctor of Philosophy in the

field of knowledge “13 – Mechanical Engineering” in the specialty “132 – Materials
Science”. – Karpenko Physico-Mechanical Institute of the National Academy of Sci-

ences of Ukraine, Lviv, 2024.
Hydrogen has emerged as a frontrunner among potential clean energy sources.

It has a high heat of combustion (~140 MJ/kg) and the absence of harmful emissions
during combustion. However, its low density in its gaseous state under normal condi-

tions poses a significant challenge for storage. Conventional hydrogen storage meth-

ods include compression into high-pressure tanks (150-700 atm) or liquefaction at

extremely low temperatures. Metal hydrides, such as magnesium hydride (MgH ),
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offer a promising alternative to traditional storage methods. Magnesium hydride

boasts several advantages: high hydrogen capacity (7,6 wt.%), cost-effectiveness and

reversibility of the sorption-desorption process.

However, its practical application is hindered by two major challenges: slow

sorption-desorption kinetics and high operating temperature requirement (around 350

°C). To address these challenges, researchers have explored various approaches, in-

cluding the use of catalytic additives and mechanical processing. Catalysts can lower

the energy needed for hydrogen sorption-desorption and improve hydrogen diffusion

into the matrix. High-energy ball milling creates a much dispersed microstructure

with a high concentration of defects within the material, which significantly increases

the speed of hydrogen sorption-desorption processes and lowers the required temper-

ature.

The most common method for obtaining hydrogen from metal hydrides is by

heating the metal hydride. Another method involves the hydrolysis of metal hydrides,

which is a fast, environmentally friendly, and energy-efficient process. Therefore,

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