In my opinion, it strongly depends on the application you are considering. E.g., for mobile applications, you want to have a storage with high gravimetric density in order reduce weight. Metal hydrides are a relative good option for that, since they can reach relatively high wt% even in a moderate temperature regime (NaAlH4, MgH2, etc.). A very interesting option in my opinion are hollow glass microspheres, They can store hydrogen up to high pressures (some of them even up to 1000 Bar or higher), with practically no safety concerns. But I would also recommend a literature review, at least to get an overview on state of the art hydrogen storage systems.

Best regards,

Stefan

I reckon you should check metal-organic frameworks (MOFs). MOFs have comparatively high gas separation and storage performance. The first step you should take is to make a literature review. Day by day new MOFs are being synthesized and benchmark data have been published. So, nobody could know the exact answer you want. Since the material selection is a complicated process, you should consider various parameters, such as operation conditions, thermal and mechanical stability, stability in the presence of water vapor, production cost etc. As a result, only you can know the answer after making a literature review.

It is indeed a bit early to answer this very general question, actually keeping busy many researches worldwide. Some of them are excellent but at low temperature (some adsorbents), others can potentially release significant amounts of H2 near room temperature but are very sensitive to oxidation and are poorly reversible (most hydrides). Still more work is required.

Alain

In my opinion, it strongly depends on the application you are considering. E.g., for mobile applications, you want to have a storage with high gravimetric density in order reduce weight. Metal hydrides are a relative good option for that, since they can reach relatively high wt% even in a moderate temperature regime (NaAlH4, MgH2, etc.). A very interesting option in my opinion are hollow glass microspheres, They can store hydrogen up to high pressures (some of them even up to 1000 Bar or higher), with practically no safety concerns. But I would also recommend a literature review, at least to get an overview on state of the art hydrogen storage systems.

Best regards,

Stefan

activated carbons are low cost option for hydrogen storage

I tend to hold the same viewpoint as Dr. Hummel. For certain applications, based on our past experience, we found the transition metal compounds to be a promising solution. These materials have been evaluated and prototype vehicles have been developed. If the application has 'modest' performance requirements (range, gravimetric density targets etc), perhaps metal hydrides offers some options.

The tank for compressed or liquid H2 is still the most applicable container.

The best hydrogen capacities correspond to chemical storage in hydrogen-containing liquids: alcohols, derivatives of biomass, which can be converted to hydrogen by way of steam reforming or others. Onboard applications are present. Sometimes, reversible hydrogen accumulation is possible.

Perspective features of hydrogen storage, reversibility and safety have the complex hydrides. However, a lot of work is needed for their commercialization.

All other considerations are based on the applications that was mentioned above.

I hope that concepts of hydrogen reservoirs, as well as practical results, will be changed by further investigations.

I agree with you.

Till now, there is not a 'perfect hydride' which accomplish all the requirements from DoE. Because of this, I think that there is still a lot to investigate and to do. In my opinion, what it is clear is that they are very promising materials for hydrogen storage.