High-Pressure Torsion of Non-Equilibrium Hydrogen Storage Materials: A Review

Ádám Révész,Marcell Gajdics

doi:10.3390/en14040819

Abstract

As the most abundant element in the world, hydrogen is a promising energy carrier and has received continuously growing attention in the last couple of decades. At the very moment, hydrogen fuel is imagined as the part of a sustainable and eco-friendly energy system, the “hydrogen grand challenge”. Among the large number of storage solutions, solid-state hydrogen storage is considered to be the safest and most efficient route for on-board applications via fuel cell devices. Notwithstanding the various advantages, storing hydrogen in a lightweight and compact form still presents a barrier towards the wide-spread commercialization of hydrogen technology. In this review paper we summarize the latest findings on solid-state storage solutions of different non-equilibrium systems which have been synthesized by mechanical routes based on severe plastic deformation. Among these deformation techniques, high-pressure torsion is proved to be a proficient method due to the extremely high applied shear strain that develops in bulk nanocrystalline and amorphous materials.

Highlights

With the continuously increasing energy demand of the world, several problems associated with energy production have become more and more important [1,2]
Bulk processing techniques [20] based on severe plastic deformation (SPD) have recently been applied very intensively to obtain hydrogen storage materials with enhanced properties [14,16,21,22]
The results showed that the nature of the initial powders has a pronounced effect, i.e., the compacts prepared from ultrafine powder obeys faster absorption kinetics than the consolidated product obtained from micro-sized atomized powder [58]

Summary

Introduction

With the continuously increasing energy demand of the world, several problems associated with energy production have become more and more important [1,2]. Notwithstanding the significant benefits, HEBM has some weaknesses in processing nanoscale hydrogen storage alloys, including the problem of scaling-up to the industrial level, exhaustive energy consumption, high production cost and potential fire risk. To address these issues, bulk processing techniques [20] based on severe plastic deformation (SPD) have recently been applied very intensively to obtain hydrogen storage materials with enhanced properties [14,16,21,22]. In the last part of the manuscript (Section 6), the improvement of H-production by HPT will be summarized

The High-Pressure Torsion Procedure

Elemental Mg and MgH2

Formation of New Hydrogen Storage Phases by HPT in Other Mg-Based Systems

Nanocrystalline Mg Catalyzed by Nanotube Additives

77.. Conclusions