Up to this point, solar has made big gains in efficiency, but nothing near what is needed to effectively compete with fossil fuels. While parity is still a ways off, researchers at Stanford have found that by making materials more resilient, producing hydrogen energy through solar could become cheap enough to compete with its dirty counterpart.
Currently, if you want to use hydrogen to power an engine, it is much more cost effective to get it from natural gas than by “splitting water” with solar. The only way for sunlight to compete with natural gas is if the solar process is between 15 and 25 percent efficient. This is double the 2013 standard.
But the team at Stanford claim that they have developed new materials that could make it possible to hit this goal, with their findings discussed in the latest issue of Science.
In order to have a chance in reaching that efficiency, the process relies on the combination of two solar cell materials, each one taking on the water-splitting roles of forming both hydrogen and oxygen.
While forming hydrogen has already been figured out for the most part, but the tricky aspect of the process is creating oxygen. At this point, Silicon is by far the best material for creating O2, but the caveat is that it corrodes very quickly. On the other side of the coin, metal oxides can last a long time, but becomes obsolete when looking at the time it takes them to actually split water (very slowly).
Knowing that silicon is our best bet currently, what the Stanford researchers did was create a protective layer of zinc (two-billionths of a meter thick) to place on top of the silicon, effectively protecting the material from corrosion for an extended period of time (days versus hours).
The team stopped the water-splitting at 3 days, and found NO damage. On top of that, the new materials were found to be “an order of magnitude faster” than metal oxides.
“Over 40 years of work on oxides has not produced a result like this.” says John Turner of the National Renewable Energy Laboratory.
The discovery is a great start, but it is stil very early in the process, and we are unlikely to see commercial production anytime soon. While three days and no corrosion is a solid outcome, we need this technology to last at least five years to become a viable option. Time to get to work.
