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The Master Key to the Problem of Reversible Chemical Hydrogen Storage is 12 kJ (mol H2)-1

revised on 12.01.2021, 02:02 and posted on 12.01.2021, 11:51 by Roland Hermann Pawelke

This article shows up the intrinsic thermodynamic boundaries to reversible mass transfer on basis of the ideal gas law and classic equilibrium thermodynamics in relation to chemical hydrogen storage. In the event, a global picture of reversible chemical hydrogen storage is unveiled, including an explanation of partial reversibility. The findings of this work help to clarify problems of metal hydride chemistry which otherwise are difficult if not impossible to solve in convergent manner, e.g. why the substitution of 4 mol % Na by K in Ti-doped NaAlH4 raises the reversible storage capacity by 42 % or the way the dopants take effect in (Rb/K)-co-doped Mg(NH2)2/2LiH. This work's result is of a wider significance since based on two cornerstones of physical chemistry and particularly for the normative role of hydrogen electrodes to electrochemistry.


ESA Contract No. 4000105330/12/NL/CLP

EDA Contract No. A-1341-RT-GP


Email Address of Submitting Author


FOTEC Forschungs- und Technologietransfer GmbH



ORCID For Submitting Author


Declaration of Conflict of Interest

There are no conflicts to declare.

Version Notes

V10: As the recognition process regarding this paper is complete, the manuscript has been given a shave with Ockham´s Razor, along some rephrasing and restructuring of the line of argument. The text up to V9 shows too much of thought processes, then important but now this should be scaled back. I deemed initially some wayward nomenclature acceptable for making a point but ultimately, this is not necessary (µ1%H°° has been changed to µ1%H°). The worked metal hydride problems ESI file has been removed and its two most interesting cases are now embedded into the text (6180 words in total). The discussion has been given a somewhat different emphasis, accordingly. The last V8 updated ESI files in relation to figures 2 and 3 are retained in V10.