UK researchers from the University of Nottingham and General Motors from Warren, Michigan, have invented a hydrogen tank material that could replace the current heavy and inefficient pressurized tubes used in today’s hydrogen-powered cars.
The material is a sponge-like substance, and can hold about 10% of its own weight in hydrogen.
Because a liter of liquid hydrogen contains just 1/4 energy of a liter of gasoline, for example, storing it is a little bit difficult, since we have to stretch the same amount of energy in the same volume, and keeping the hydrogen purely liquid is not an option.
Previous attempts to make a material to hold hydrogen have been giving results of 6 to 7.5% of their weight in hydrogen. This figure covers the DOE 2010 imposed standards, but it seems like these scientists made a step further, even if with some sacrifices and complications in the storing environment.
Their sponge-like material is made of a combination of copper atoms and organic molecules. This setup is called a “metalic-organic framework”, and has each copper atom surrounded by a polyhedral “cage” of the organic molecules. These cages slot together, forming a very porous material with great hydrogen bondage capabilities.
Martin Schri¶der said that the 10% figure is a real number, that has been achieved by experiments, but it can only be obtained at 77 atmospheres and -196 °C, fact that limits the range of useful real-life applications. Low temperatures are needed because the weak inter-molecular forces that hold hydrogen within the material are only strong enough to latch onto hydrogen molecules made sluggish by the cold.
Anyway, this is an interesting idea and a starting point showing how we could make tanks smaller and safer for being used in cars. When this kind of technology will come to life, remains to be seen.