In the past decade, researchers have made significant efforts to synthesize and isolate atomic-scale energy materials structures with vastly enhanced performance. Such technological improvements lead to greater energy savings, lower energy costs, and carbon emission reductions. Two materials, in particular, continue to receive a lot of attention in the news: graphene and silicene.
Both graphene and silicene are critical energy materials because they have properties or functionalities that enable the generation, transmission, or storage of energy in the form of heat or power. Generally speaking, such energy materials have higher performance when scaled down in size, ideally to atomic scale. The drive for one-atom-thick, high-performing materials continues to form the basis for advancing graphene- and silicene-based technologies.
Graphene is the thinnest, lightest, and strongest substance that humans have ever synthesized. It also shatters records for being one of the most electrically and thermally conductive materials ever known. The existence of this one-atom-thick hexagonal lattice of carbon atoms had been theorized for over half a century and was finally isolated in a laboratory in 2004.
Silicene is a relatively new but burgeoning research area because of its promise to revolutionize transistors—a key component of computers. This past year, scientists successfully created the first silicene transistor, which had been theorized more than 20 years ago.
Energy materials are a major focus area for researchers and professional societies. About four years ago, Nexight Group collaborated with The Minerals, Metals and Materials Society (TMS) to identify breakthrough research opportunities in energy materials and manufacturing technologies that are foundational to the clean energy age. Below are three examples of applications that demonstrate why professional societies like TMS want to investigate the potential for game-changing materials like graphene and silicene to shape our energy future:
- Solar cells (energy generation): Most commercial solar panels have power conversion efficiencies of nearly 20 percent, but graphene/metal oxide nanocomposites currently only achieve a conversion efficiency of 15.6 percent. While some experts believe graphene-based solar cells will soon reach efficiencies of 20 percent as they move closer to commercialization, others claim that graphene cells might actually have a theoretical limit of over 60 percent efficiency. Once these comparable or advanced efficiencies are achieved, graphene’s low processing temperature will help reduce the cost of production of solar cells, making graphene a fierce competitor in the renewable energy technology market. Graphene could play a key role in supporting the SunShot Initiative’s goal of solar energy providing 14 percent of total U.S. electricity demand by 2030 and 27 percent by 2050.
- Electronics (energy transmission): Step aside, copper. When it comes to thermal and electrical properties, graphene comes out substantially ahead. Graphene’s high electrical conductivity facilitates minimal signal loss in data transmissions, and its high heat capacity makes it suitable for dissipating heat and increasing processing efficiency in computer chips. IBM researchers even reported that they used ultra-conductive graphene to line transistor channels in radio frequency ID (RFID) chips, enabling them to operate 10,000 times faster than current silicon counterparts. Silicene has similar electrical properties to graphene, but its electron configuration elevates the potential for silicene to be a game-changing semiconductor material in next-generation electronics, as long as scientists can adequately address its substrate and degradation issues.
- Supercapacitors (energy storage): Conductive materials with high surface areas allow capacitors to store electrical energy more effectively. Because graphene has such properties, it’s an attractive material for research and development activities in this area. Two one-atom-thick layers of graphene and a thin carbon nanotube film form an electrolytic “sandwich” that gives engineers the basis for creating thin, transparent, flexible electronic devices. If the Department of Defense (DoD) selects the technical focus area of flexible hybrid electronics for the next Institute for Manufacturing Innovation (IMI), there is a good chance that graphene-based supercapacitors would be commercialized much sooner than currently anticipated. The sooner they are commercialized, the sooner we’ll see lightweight, battery-free electric vehicles.
We are just beginning to experience the energy, cost, and emissions benefits possible from advanced energy materials like graphene and silicene. As we continue to work toward realizing a clean energy future, key advances in manufacturing technologies are needed to successfully fabricate and achieve the potential of next-generation graphene- and silicene-based energy materials.