A little sodium goes a long way. At least that's the case in carbon-based energy technology. Specifically, embedding sodium in carbon materials can tremendously improve electrodes.
A research team led by Yun Hang Hu, the Charles and Carroll McArthur Professor of materials science and engineering at Michigan Tech, created a brand-new way to synthesize sodium-embedded carbon nanowalls. Previously, the material was only theoretical and the journal Nano Letters recently published this invention.
High electrical conductivity and large accessible surface area, which are required for ideal electrode materials in energy devices, are opposed to each other in current materials. Amorphous carbon has low conductivity but large surface area. Graphite, on the other hand, has high conductivity but low surface area. Three-dimensional graphene has the best of both properties--and the sodium-embedded carbon invented by Hu at Michigan Tech is even better.
"Sodium-embedded carbon's conductivity is two orders of magnitude larger than three-dimensional graphene," Hu says. "The nanowall structure, with all its channels and pores, also has a large accessible surface area comparable to graphene."
This is different from metal-doped carbon where metals are simply on the surface of carbon and are easily oxidized; embedding a metal in the actual carbon structure helps protect it. To make such a dream material, Hu and his team had to create a new process. They used a temperature-controlled reaction between sodium metal and carbon monoxide to create a black carbon powder that trapped sodium atoms. Furthermore, in collaboration with researchers at University of Michigan and University of Texas at Austin, they demonstrated that the sodium was embedded inside the carbon instead of adhered on the surface of the carbon. The team then tested the material in several energy devices.
In the dye-sensitized solar cell world, every tenth of a percent counts in making devices more efficient and commercially viable. In the study, the platinum-based solar cell reached a power conversion efficiency of 7.89 percent, which is considered standard. In comparison, the solar cell using Hu's sodium-embedded carbon reached efficiencies of 11.03 percent.
Supercapacitors can accept and deliver charges much faster than rechargeable batteries and are ideal for cars, trains, elevators and other heavy-duty equipment. The power of their electrical punch is measured in farads (F); the material's density, in grams (g), also matters.
Activated carbon is commonly used for supercapacitors; it packs a 71 F g-1 punch. Three-dimensional graphene has more power with a 112 F g-1 measurement. Sodium-embedded carbon knocks them both out of the ring with a 145 F g-1 measurement. Plus, after 5,000 charge/discharge cycles, the material retains a 96.4 percent capacity, which indicates electrode stability.
Hu says innovation in energy devices is in great demand. He sees a bright future for sodium-embedded carbon and the improvements it offers in solar tech, batteries, fuel cells, and supercapacitors.
Allison Mills | EurekAlert!
Novel sensors could enable smarter textiles
17.08.2018 | University of Delaware
Quantum material is promising 'ion conductor' for research, new technologies
17.08.2018 | Purdue University
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences