9. Conclusions and outlook

One of the major challenges currently facing research is the development of electric vehicles powered by low-temperature (80°C) fuel cells based on proton exchange polymer membranes (PEMFC). These cells consume around 1 kg of hydrogen per 100 km, so it is necessary to store around 5 kg per vehicle to give it a range close to that of today's combustion-powered vehicles.

The most important criterion for this application is therefore the mass storage capacity, without neglecting the value of volume capacity and safety. Three storage modes best meet this criterion. However :

• compressed hydrogen storage has two major drawbacks: the size of the tank and the safety problems associated with high storage pressure (700 bar);

• storing liquefied hydrogen requires liquefaction energy equal to a...