Russian Physics Journal, Vol. 61, No. 2, June, 2018 (Russian Original No. 2, February, 2018)
HYDROGEN SORPTION PROPERTIES OF POTASSIUM ALANATE
Z. A. Matysina,
S. Yu. Zaginaichenko,
D. V. Schur,
UDC 456 623:542.92
Al. D. Zolotarenko,
An. D. Zolotarenko,
and M. T. Gabdulin
Molecular kinetic representations were used to develop the statistical theory of phase transformations of
thermal decomposition of KAlH
potassium alanate with formation of a more complex K
alanate and KH
potassium hydride and subsequent dehydrogenation of the latter accompanied with free hydrogen, pure
potassium and aluminum yield. Temperature dependence of the emitted free hydrogen was established.
Isotherms and isopleths were built. The possibility of hysteresis effect manifestation was established. The
results of calculations were compared to the experimental data.
Keywords: potassium alanates KAlH
, hydrides of bialkali alanates K
isotherms and isopleths.
Alanates of alkali metals, particularly potassium alanates, draw researchers’ attention by being unique and
promising accumulators of hydrogen – an environmentally friendly and harmless source of energy.
The study of alanates (that are complex hydrides) and simple hydrides of alkali metals started as early as in the
In the early 21
century researchers began to study alanates of alkali metals as possible reversible accumulators
and depositories of hydrogen [1–11]. Potassium alanates KAlH
are the most advantageous in that respect.
First, they are more stable compared to, for instance, sodium and lithium alanates. Second, they have moderate
hydrogenation temperature. Third, they ensure reversible hydrogen sorption. Fourth, absorption–desorption processes
can occur without catalysts. Fifth, they contain up to 5.71 wt.% H
and offer hydrogen yield of 4.3 wt.% without the
high-temperature decomposition of KH potassium hydride. Finally, they are easy to produce by direct synthesis.
Therefore, in the future potassium alanates may offer opportunities for reversible accumulation of hydrogen. These are
new hydrogen accumulators.
Over the recent years, researchers have begun to study complex mixed bialkali alanates K
(M = Na, Li)
[5, 8], selection of the right composition of which may help develop their synthesis modes and optimize the processes of
hydrogen absorption–desorption in them.
With the rise in temperature alanates produced at relatively low temperature and pressure are subjected to
decomposition in two-three stages. For potassium alanate the thermal phase transformations proceed according to the
following chemical reactions:
I. N. Frantsevich Institute for Problems of Materials Science, Ukrainian National Science Academy, Kiev,
Ukraine, е-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org;
Al-Farabi Kazakh National University, Almaty,
Kazakhstan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 44–53, February, 2018.
Original article submitted January 19, 2017; revision submitted September 28, 2017.
1064-8887/18/6102-0253 2018 Springer Science+Business Media, LLC