However, an exceptionally low density of gaseous hydrogen and its high diffusivity under pressure make hydrogen storage a particularly difficult problem. 

For example, to store hydrogen at a normal ambient temperature, a pressure of more than 60 MPa is required. On the other hand, it is no less dangerous to store hydrogen in its liquid state aboard a vehicle, because its storage requires a low temperature of lower than −252.9°C (−423°F).​ 

When the temperature rises, the liquid hydrogen boils continuously, necessitating release of constantly evaporating gaseous hydrogen to the atmosphere.

A safer way to power a vehicle’s hydrogen fuel cells  or hydrogen ​combustion engine is to avoid storing hydrogen aboard, but rather producing it on demand.

Our team of inventors established the following requirements for the hydrogen/electric power source:

• The device must be portable to conveniently fit within a compact passenger car;
• The rate of hydrogen evolution reaction must be sufficient to provide enough power to the vehicle’s power unit of not less than 30 kW;
• The hydrogen evolution reaction must be manageable, i.e. the hydrogen release rate should vary on demand from 0 to 100% output;
• The device must not contain or consume expensive, rare, toxic and hazardous substances;
• The device must be simple, reliable and cheap.

High-capacity, dry-charged, ready-for-instant-activation-by-adding-water, easily-replaceable, non-rechargeable, recyclable and safe electrochemical cell for producing hydrogen and electrical energy on demand, based on electrochemical interactions of magnesium, water and sulfuric acid.

Magnesium is one of the most energy-intensive materials for chemical sources of electrical energy - about 1100 Wh/kg. In addition, magnesium does not corrode in air or room- temperature water.