Hydrogen Solid State Storage on MgH2 Compacts for Mass Applications

Abstract

The mass storage of hydrogen is a challenge considering large industrial applications and continuous distribution, e.g., for domestic use as a future energy carrier that respects the environment. For a long time, molecular hydrogen was stored and distributed, either as a gas (pressurized up to 75 MPa) or as a cryogenic liquid (20.4 K). Furthermore, the atomic storage of hydrogen in the solid-state form via metallic or covalent compounds is still the subject of intense research and limited to a small scale for some practical developments. In addition, other type H chemical storage routes are being tested, such as ammonia and LOHC (Liquid Organic Hydrogen Carrier), etc. In any case, the main constraint remains security. However, Hydrogen Solid State Storage (HSSS) using MgH2 bodies has been shown to be feasible in terms of process and safety. Furthermore, its intrinsic volumetric densification was proven to be much better performing with 106:70:45 kgH2/m3 for solid (RT):LH (20.4 K):gas (75 MPa), respectively. Very early on, fairly reactive MgH2-based pellets were produced (for max. ~27 tons/year) at McPhy Energy using a series of unique and self-built installations. Thus, the design of large instrumented reservoirs was undertaken thanks to fundamental research first carried out at the CNRS. So, prototypes of storage units from 100 to ~5500 kWh have been produced. However, McPhy took other routes a few years ago (smelting and refueling stations) because the HSSS market was not merging at that time. Today, a new operator, Jomi–Leman, therefore, decided to try the challenge again focusing on applications with on-site production and mass HSSS.

Instances of Safety-Related Advances on Hydrogen as Regards Its Gaseous Transport and Buffer Storage and Its Solid-State Storage☆

“…Industries that need large quantities of hydrogen, such as the steel, cement, chemical, or glass industries, as well as large refuelling stations, will eventually be able to use large solid-state hydrogen storage units operating on site and supplied with green hydrogen (renewably-sourced) in complete safety (pressure < 15 bar) [4].…”

“…Section 2 of this paper serves as a reminder of the safety considerations, codes, and standards as well as of the lessons learnt in relation to hydrogen. This section also serves as an introduction for the following sections that describe two instances of advances which are both committed to improving safety [3,4] and therefore fall within the global search for environmentally friendly energy solutions that are safe by design [5][6][7]. These instances relate to two essential sectors of the hydrogen infrastructure, namely transport and storage.…”

“…In another area of development, solid-state storage, which involves storing hydrogen in solid materials such as metal hydrides, chemical hydrides, or adsorbents, offers high volumetric energy densities and improved safety compared to gaseous or liquid storage [1,[14][15][16]. Magnesium hydride (MgH₂), with its high hydrogen storage capacity, relative lower cost, good reversibility, abundant natural reserves, and environmental friendliness, has been the subject of extensive research over the past decade [4,10,17,18]. Noticeably, whereas McPhy-Energy produced fairly reactive MgH₂-based pellets very early on [19], better conditions for the development of mass applications seem to be emerging now [4].…”

“…Magnesium hydride (MgH₂), with its high hydrogen storage capacity, relative lower cost, good reversibility, abundant natural reserves, and environmental friendliness, has been the subject of extensive research over the past decade [4,10,17,18]. Noticeably, whereas McPhy-Energy produced fairly reactive MgH₂-based pellets very early on [19], better conditions for the development of mass applications seem to be emerging now [4].…”

Synergetic Effect of FeTi in Enhancing the Hydrogen-Storage Kinetics of Nanocrystalline MgH2

“…It was pointed out in another research study that industrial vessels filled with several hundred kg of FeTi-or Mg-based alloys can operate in the temperature range of 100-400 • C with a hydrogen capacity of 2-15 kg [63]. Operational upscaling of MgH 2 -based composite production was implemented recently at McPhy Energy [64]. As a main step of production, powders were processed in an industrial ball mill with a yield of 20 kg per batch, equivalent to an annual amount of 27 tons.…”