A decade after being thrust into the scientific limelight, graphene remains one of the hottest areas of materials research. One particularly important area is composites—a combination of graphene and one or more other materials, where graphene can enhance the electrical or mechanical properties of the other material. It is often critical that composite materials have specifically designed nanoscale structures. Despite much progress in hybridizing graphene and nanoparticles, the challenge still exists to control the morphology, surface coverage, and other properties of nanoparticles on graphene sheets.
The group of Yitai Qian at the University of Science and Technology of China has recently devised a new fabrication route to uniformly wrap metal-oxide nanoparticles of different shapes with graphene oxide and reduced graphene oxide sheets. Their synthesis route is driven by electrostatic attraction between negatively charged graphene oxide and positively charged metal nanoparticles, which coagulate upon mixing, allowing the graphene-oxide encapsulated nanoparticle to be easily collected and chemically reduced. The advantages of this new approach are that it can be performed at room temperature and that the size and structure of the nanoparticles used remains unchanged after encapsulation.
In addition to developing a new platform that can be extended to various nanomaterials, the composites made in this study exhibit enhanced electrochemical performance and lithium storage potential when integrated into a lithium-ion battery.