[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Lawrence Livermore team shows carbon nanotube porins are fastest known proton conductors; potential application for PEM fuel cells
April 05, 2016
Lawrence Livermore National Laboratory (LLNL) researchers have shown that 0.8-nm-diameter carbon nanotube porins, which promote the formation of one-dimensional water wires, can support proton transport rates exceeding those of bulk water by an order of magnitude.
The transport rates in these nanotube pores also exceed those of biological channels and Nafion—one of the most common and commercially available membranes for proton exchange membrane (PEM fuel cells). Carbon nanotubes are the fastest known proton conductor. The research appears in the journal Nature Nanotechnology. Practical applications include proton exchange membranes (PEMs); proton-based signaling in biological systems; and the emerging field of proton bioelectronics (protonics).
NREL reveals thermoelectric potential for tailored semiconducting carbon nanotubes
A finely tuned carbon nanotube thin film has the potential to act as a thermoelectric power generator that captures and uses waste heat, according to researchers at the Energy Department’s National Renewable Energy Laboratory (NREL).
The research could help guide the manufacture of thermoelectric devices based on either single-walled carbon nanotube (SWCNT) films or composites containing these nanotubes. Because more than half of the energy consumed worldwide is rejected primarily as waste heat, the idea of thermoelectric power generation is emerging as an important part of renewable energy and energy-efficiency portfolios.
PNNL team develops higher-strength, lower-cost titanium alloy aimed at improving vehicle fuel economy and reducing CO2 emissions
April 02, 2016
An improved titanium alloy—stronger than any commercial titanium alloy currently on the market—gets its strength from the novel way atoms are arranged to form a special nanostructure. For the first time, a team led by researchers at Pacific Northwest National Laboratory (PNNL) have been able to see this alignment and then manipulate it to make the strongest titanium alloy (hierarchical nanostructured Ti-185, or HNS Ti-185) yet developed. On top of the gains in strength, the new alloy benefits from a lower cost process.
In an open access paper published in the journal Nature Communications, the researchers note that that material is an excellent candidate for producing lighter vehicle parts, and that this newfound understanding may lead to creation of other high strength alloys.
ORNL team gains insight into elastic properties of next-gen energy storage material MXene; understanding how ions flow
March 16, 2016
Researchers at Oak Ridge National Laboratory, with a colleague from Drexel University, have combined advanced in-situ microscopy and theoretical calculations to uncover important clues to the elastic properties of an MXene material—a promising next-generation energy storage material for supercapacitors and batteries—(earlier post), specifically a 2D titanium carbide (Ti3C2Tx).
MXene material—which acts as a two-dimensional electrode that could be fabricated with the flexibility of a sheet of paper—is based on MAX-phase ceramics (ternary carbides), discovered two decades ago by Michel Barsoum, PhD, Distinguished professor in Drexel’s Department of Materials Science & Engineering. Chemical removal of the “A” layer leaves two-dimensional flakes composed of transition metal layers—the “M”—sandwiching carbon or nitrogen layers (the “X”) in the resulting MXene, which physically resembles graphite.
Hybrid cellular nanosheets show promise as basis for high performance anodes for Li-ion batteries
September 14, 2015
Researchers in S. Korea have developed a simple synthetic method for producing carbon-based hybrid cellular nanosheets that exhibit strong electrochemical performance for many key aspects of high-performance lithium-ion battery anodes. The nanosheets consist of close-packed cubic cavity cells partitioned by carbon walls, resembling plant leaf tissue.
Loading the carbon cellular nanosheets with SnO2 nanoparticles as a model system, the team found that the resulting anode materials showed a specific capacity of 914 mAh g–1 on average with a retention of 97.0% during 300 cycles. When the cycling current density was increased from 200 to 3000 mA g–1, the reversible capacity was decreased by only 20% from 941.3 to 745.5 mAh g–1. A paper on their work is published in the Journal of the American Chemical Society.
Rice team demonstrates plasmonic hot-electron solar water-splitting technology; simpler, cheaper and efficient
September 05, 2015
Researchers at Rice have demonstrated an efficient new way to use solar energy for water splitting. The technology, described in a paper in the ACS journal Nano Letters, relies on a novel plasmonic photoelectrode architecture of light-activated gold nanoparticles that harvest sunlight to drive photocatalytic reactions by efficient, non-radiative plasmon decay into “hot carriers”—highly excited electrons.
In contrast to past work, the new architecture does not utilize a Schottky junction—the commonly used building block to collect hot carriers. Instead, the team observed large photocurrents from a Schottky-free junction due to direct hot electron injection from plasmonic gold nanoparticles into the reactant species upon plasmon decay.
Argonne researchers develop macroscale superlubricity system with help of Mira supercomputer; potential for “lubricant genome”
July 22, 2015
Argonne scientists have used the Mira supercomputer to identify and to improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity—a state in which friction essentially disappears—at the macroscale—i.e., at engineering scale—for the first time. A paper on their work was published in the journal Science.
They showed that superlubricity can be realized when graphene is used in combination with nanodiamond particles and diamond-like carbon (DLC). Simulations showed that sliding of the graphene patches around the tiny nanodiamond particles led to nanoscrolls with reduced contact area that slide easily against the amorphous diamond-like carbon surface, achieving incommensurate contact and a substantially reduced coefficient of friction (~0.004).