More potential uses for the carbon monolayer graphene have been described, but manufacturing the material continues to be a stumbling block
Graphene, it seems, has great potential as a material for armour, but it isn’t impenetrable, according to two strands of new research. It lets protons pass through; making it a promising material to improve the efficiency of fuel cells.
In paper co-authored by graphene discoverer André Geim, published in the journal Nature, a team at the University on Manchester describes how a sheet of grapheme could act as a perfect membrane in a fuel cell, separating allowing protons to flow inside the cell while electrons form a current in a circuit outside the cell. Current membranes allow hydrogen atoms to leak through in the opposite direction, which reduces the proton flow and thereby cuts the current the cell can generate.
The technique is not simple, though. It’s still largely theoretical, as it depends on being able to make graphene in sufficiently large and clean sheets: something which is currently not possible.
Another Nature paper, from Rice University in Houston, Texas, describes how graphene layers can disperse the impact force of silica spheres — the first time such impact tests have been described. The force dispersion works because graphene ‘ripples’ when struck, the team says, and the speed at which a ripple can spread through a material defines how much force it can disperse. The upper limit is the speed of sound in the material, and in graphene, this is 22km/sec —around 65 times as fast as sound can travel in air. This would make it a good candidate as a material for a composite ballistic armour, says paper co-authour Edwin Thomas.
Although promising, this application has the same drawback as the fuel cell use – manufacture of graphene in sufficient quantity and quality.