03 Mar 2016
“Our climate change solution is two fold: To transform the greenhouse gas carbon dioxide into valuable products and to provide greenhouse gas emission-free alternatives to today’s industrial and transportation fossil fuel processes,” Stuart Licht, professor of chemistry at George Washington University
An interdisciplinary team of scientists has worked out a way to make electric vehicles that are not only carbon neutral, but carbon negative, capable of actually reducing the amount of atmospheric carbon dioxide as they operate. They have done so by demonstrating how the graphite electrodes used in the lithium-ion batteries that power electric automobiles can be replaced with carbon material recovered from the atmosphere.
The recipe for converting carbon dioxide gas into batteries is described in a paper published in the March 2 issue of the journal ACS Central Science (“Carbon Nanotubes Produced from Ambient Carbon Dioxide for Environmentally Sustainable Lithium-Ion and Sodium-Ion Battery Anodes”).
The Solar Thermal Electrochemical Process (STEP) converts atmospheric carbon dioxide into carbon nanotubes that can be used in advanced batteries. (Image: Julie Turner, Vanderbilt University)
“Our climate change solution is two fold: To transform the greenhouse gas carbon dioxide into valuable products and to provide greenhouse gas emission-free alternatives to today’s industrial and transportation fossil fuel processes,” Stuart Licht, professor of chemistry at George Washington University said.
“In addition to better batteries other applications for the carbon nanotubes include carbon composites for strong, lightweight construction materials, sports equipment and car, truck and airplane bodies.” The unusual pairing of carbon dioxide conversion and advanced battery technology is the result of a collaboration between Dr. Licht, and the laboratory of assistant professor of mechanical engineering Cary Pint at Vanderbilt University. Licht adapted the lab’s solar thermal electrochemical process (STEP) so that it produces carbon nanotubes from carbon dioxide and with Pint by incorporating them into both lithium-ion batteries like those used in electric vehicles and electronic devices and low-cost sodium-ion batteries under development for large-scale applications, such as the electric grid. In lithium-ion batteries, the nanotubes replace the carbon anode used in commercial batteries.
The team demonstrated that the carbon nanotubes gave a small boost to the performance, which was amplified when the battery was charged quickly. In sodium-ion batteries, the researchers found that small defects in the carbon, which can be tuned by STEP, can unlock stable storage performance over 3.5 times above that of sodium-ion batteries with graphite electrodes. Most importantly, both carbon-nanotube batteries were exposed to about 2.5 months of continuous charging and discharging and showed no sign of fatigue.
Published on Feb 25, 2016: Video interview with Cary Pint explaining this research.
Scientists from Vanderbilt and George Washington universities have worked out a way to make electric vehicles not just carbon neutral but carbon negative by demonstrating how the graphite electrodes used in the lithium-ion batteries can be replaced with carbon recovered from the atmosphere.
|“This trailblazing research has achieved yet another amazing milestone with the incorporation of the carbon nanotubes produced by Stuart Licht’s STEP reduction of carbon dioxide process into batteries for electric vehicles and large scale storage,” said Michael King, chair of GW’s Department of Chemistry. “We are thrilled by this translation of basic research into potentially useful consumer products while mitigating atmospheric carbon dioxide buildup. This is a win-win for everyone!”|
|The researchers estimate that with a battery cost of $325 per kWh (the average cost of lithium-ion batteries reported by the Department of Energy in 2013), a kilogram of carbon dioxide has a value of about $18 as a battery material – six times more than when it is converted to methanol – a number that only increases when moving from large batteries used in electric vehicles to the smaller batteries used in electronics.
And unlike methanol, combining batteries with solar cells provides renewable power with zero greenhouse emissions, which is needed to put an end to the current carbon cycle that threatens future global sustainability.
|Licht also proposes a modified flue system for combustion plants that incorporates this process could be self-sustaining, as exemplified by a new natural gas power plant with zero carbon dioxide emissions. That’s because the side product of the process is pure oxygen, which plants could then use for further combustion. The calculated total cost per metric tonne of CNTs would be much less expensive than current synthetic methods.|
|“This approach not only produces better batteries but it also establishes a value for carbon dioxide recovered from the atmosphere that is associated with the end-user battery cost unlike most efforts to reuse CO2 that are aimed at low-valued fuels, like methanol, that cannot justify the cost required to produce them,” said Pint.|
|Source: Vanderbilt University|
Genesis Nanotechnology, Inc. ~ “Great Things from Small Things”
Posted: Mar 01, 2016
Researchers involved in a national effort to develop cancer treatments that harness nanotechnology are recommending pivotal changes in the field because experiments with laboratory animals and efforts based on current assumptions about drug delivery have largely failed to translate into successful clinical results.
The assessment was advanced in a perspective piece that (“Targeting the Tumor Microenvironment”; pdf) appeared in the National Cancer Institute’s Cancer Nanotechnology Plan 2015, a 10-year roadmap concerning the use of nanotechnology to attack cancer.
The complex microenvironment of tumors is presenting a challenge in developing effective anticancer treatments
The complex microenvironment of tumors is presenting a challenge in developing effective anticancer treatments that attempt to harness nanotechnology. Researchers are recommending pivotal changes in the field of cancer nanotechnology because experiments with laboratory animals and efforts based on current assumptions about drug delivery have largely failed to translate into successful clinical results. (Image: Bumsoo Han, Kinam Park, Murray Korc) (click on image to enlarge)
Researchers are trying to perfect “targeted delivery” methods using various agents, including an assortment of tiny nanometer-size structures, to selectively attack tumor tissue. However, the current direction of research has brought only limited progress, according to the authors of the article.
“The bottom line is that so far there are only a few successful nanoparticle formulations approved and clinically used, so we need to start thinking out of the box,” said Bumsoo Han, a Purdue University associate professor of mechanical and biomedical engineering.
One approach pursued by researchers has been to design nanoparticles small enough to pass through pores in blood vessels surrounding tumors but too large to pass though the pores of vessels in healthy tissue. The endothelial cells that make up healthy blood vessels are well organized with tight junctions between them. However, the endothelial cells in blood vessels around tumors are irregular and misshapen, with loose gaps between the cells.
“We should realize that having a specific nanosize or functionality alone is not enough to guarantee good drug delivery to target tumors,” said Kinam Park, a professor of pharmaceutics and Purdue’s Showalter Distinguished Professor of Biomedical Engineering. “The tumor microenvironment is just too complex to overcome using this strategy alone.”
The two authored the article with Murray Korc, the Myles Brand Professor of Cancer Research at the Indiana University School of Medicine.
The authors pointed out that research with laboratory mice has rarely translated into successful clinical results in humans, suggesting that a more effective approach might be to concentrate on research using in-vitro experiments that mimic human physiology. For example, one new system under development, called a tumor-microenvironment-on-chip (T-MOC) device, could allow researchers to study the complex environment surrounding tumors and the barriers that prevent the targeted delivery of therapeutic agents.
The approach could help drug makers solve a daunting obstacle: even if drugs are delivered to areas near the target tumor cells, the treatment still is hindered by the complex microenvironment of tumors.
“We used to think that if we just killed the tumor cell it would cure the cancer, but now we know it’s not just the cancer cells alone that we have to deal with,” Korc said. “There are a lot of different cells and blood vessel structure, making for a complex environment that supports the cancer cells.”
An “extracellular matrix” near tumors includes dense collagen bundles and a variety of enzymes, growth factors and cells. For example, surrounding pancreatic tumors is a “stromal compartment” containing a mixture of cells called stromal cells, activated cancer-associated fibroblasts and inflammatory immune cells.
“Particularly for pancreatic cancer, the stromal tissue is much bigger than the tumor itself,” Korc said.
In addition, a compound called hyaluronic acid in this stromal layer increases the toughness of tumor microenvironment tissue, making it difficult for nanoparticles and drugs to penetrate.
“It’s dense, like scar tissue, so it’s more difficult for drugs coming out of the blood vessel to diffuse through this tissue,” Han said.
Another challenge is to develop water-soluble drugs to effectively deliver medicines.
“The cancer drugs need to be aqueous because the body resorbs them better, but a lot of the current chemotherapy drugs have low solubility and usually need different types of solvents to increase their solubility,” Park said.
The T-MOC approach offers some hope of learning how to design more effective cancer treatments.
“Recent advances in tissue engineering and microfluidic technologies present an opportunity to realize in-vitro platforms as alternatives to animal testing,” Park said. “Tumor cells can be grown in 3D matrices with other relevant stromal cells to more closely mirror the complexity of solid tumors in patients. The current ability of forming 3D-perfused tumor tissue needs to be advanced further to create an accurate tumor microenvironment.”
Such a major shift in research focus could play a role in developing personalized medicine, or precision medicine, tailored to a particular type of cancer and specific patients. More effective treatment might require various “priming agents” in combination with several drugs to be administered simultaneously or sequentially.
“This kind of research currently involves a very large number of experiments, and it makes animal testing expensive and time consuming,” Park said. “Moreover, small animal data have not been good predictors of clinical outcome. Thus, it is essential to develop in-vitro test methods that can represent the microenvironment of human tumors.”
Source: By Emil Venere, Purdue University