Scientists make energy storage breakthrough

Rice University scientists make molybdenum disulfide discovery.

A research team from Rice University has managed to transform the two dimensional form of molybdenum disulfide into a nanoporous film that can be used for energy storage or can catalyze hydrogen production.

Developing flexible films of the material could be cost-effective for fuel cells.

Molybdenum disulfide (MoS2) is a semiconductor that is made up of a layer of sulfur atoms that are situated between two layers of molybdenum, a brittle transition metal. From above, the material looks like graphene, but when turned on its side one can see atoms sandwiched together in three distinct layers. This layered and fairly thick structure gives the material a greater robust edge for catalytic reactions and energy storage. More specifically, studies have determined that the material’s edges serve as extremely efficient catalysts for a process that is utilized in fuel cells for the purpose of pulling hydrogen from water, which is known as hydrogen evolution reaction (HER). The new film was developed by James Tour (a Rice chemist), Yang Yang (a postdoctoral researcher), Huilong Fei (a graduate student), and their colleagues. Together, the team discovered a cost-effective method for developing flexible films of MoS2 that make the most use out of the exposed edge and creates potential for various applications that are energy-oriented.

The films can also provide quick energy storage.

In addition, the films have the capability of storing energy by serving as supercapacitors. This enables them to rapidly store energ as static charge which is released in a burst. Even though the amount of energy that can be stored pales in comparison to an electrochemical battery, these supercapcitors have a long life and are widely used due to the fact that they have the ability to deliver greater power compared to a battery. In tests, the supercapacitors built by the Rice lab using the films preserved 90% of their capacity after 10,000 charge-discharge cycles and, after 20,000 cycles, they retained 83%. Tour said that “We see anodization as a route to materials for multiple platforms in the next generation of alternative energy devices.” He added that “These could be fuel cells, supercapacitors and batteries. And we’ve demonstrated two of those three are possible with this new material.” The new energy storage and hydrogen research from Rice University can be found in the journal, Advanced Materials.